Mollie Wood

• Krogsrud, Stine Kleppe; Nordeng, Hedvig Marie Egeland; Roe, James Michael; Torkildsen, Janne von Koss; Wood, Mollie Elizabeth & Ystrøm, Eivind (2025). Associations between prenatal paracetamol exposure and brain development from ages 4–16: A longitudinal MRI study. Developmental Cognitive Neuroscience. ISSN 1878-9293. 78. doi: 10.1016/j.dcn.2025.101667. Fulltekst i vitenarkiv Vis sammendrag

  Research has raised concerns regarding the potential impact of prenatal paracetamol exposure on fetal neurodevelopment. This is the first longitudinal study to investigate whether such exposure is related to structural brain development and cognitive abilities during childhood and adolescence. The sample includes 447 children aged 4.1–16.2 years with 905 MRI scans. The study is based on The Norwegian Mother, Father and Child Study (MoBa), and uses data from the Medical Birth Registry of Norway. The exposure variable is mothers’ self-reported use of paracetamol from prenatal and postnatal questionnaires. Among 447 children (229 girls; mean age 8.38 years), 193 (43.2 %) were prenatally exposed. Days of exposure range from 1 to 128 (mean 8.2). Vertex-wise linear mixed effect models showed that exposed children (n = 193; 393 scans) had slightly smaller cortical surface area and volume in some regions compared to non-exposed children. These results were seemingly driven by long-term exposed children (≥14 days in utero; n = 35; 72 scans, and exposed in all three trimesters, n = 21; 44 scans). However, group differences in brain structure were small with largely overlapping distributions, and the observational design and risk of unmeasured confounding preclude causal inference. Thus, the clinical significance remains uncertain. For cognitive abilities, results were reassuring showing no significant effect of prenatal paracetamol exposure on working memory capacity or IQ scores.

• Pavlović, Milena; Hajj, Ghadi al; Kanduri, Chakravarthi; Pensar, Johan; Wood, Mollie Elizabeth & Sollid, Ludvig Magne [Vis alle 8 forfattere av denne artikkelen] (2024). Improving generalization of machine learning-identified biomarkers using causal modelling with examples from immune receptor diagnostics. Nature Machine Intelligence. 6(1), s. 15–24. doi: 10.1038/s42256-023-00781-8. Fulltekst i vitenarkiv
• Harris, Gerd Marie Eskerud; Wood, Mollie; Ystrøm, Eivind & Nordeng, Hedvig Marie Egeland (2022). Association of Maternal Use of Triptans during Pregnancy with Risk of Attention-Deficit/Hyperactivity Disorder in Offspring. JAMA Network Open. 5(6). doi: 10.1001/jamanetworkopen.2022.15333. Fulltekst i vitenarkiv Vis sammendrag

  Importance Triptans are commonly used in the treatment of migraine. Prenatal exposure to triptans may be associated with adverse fetal neurodevelopment; however, there is limited information about the long-term safety of triptan use during pregnancy. Objective To examine the association between maternal use of triptans during pregnancy and diagnosis and symptoms of attention-deficit/hyperactivity disorder (ADHD) among offspring. Design, Setting, and Participants This study used data from the Norwegian Mother, Father and Child Cohort Study (recruitment 1999-2008), linked to national health registries. Live-born singleton children born to women with migraine before or during pregnancy were included. Two analytic samples were defined: one to assess ADHD diagnosis and one to assess ADHD symptoms. Data were analyzed from May 1 to November 30, 2021. Exposure Maternal self-report of triptan use during pregnancy. Exposed children were compared with 2 groups of unexposed children whose mothers reported migraine (1) during pregnancy and (2) before pregnancy only. Main Outcomes and Measures An ADHD diagnosis was defined as diagnosis of hyperkinetic disorder or receipt of dispensed ADHD medication. Symptoms of ADHD at 5 years were measured by the Conners’ Parent Rating Scale, where a higher score indicates more symptoms of ADHD. Cox proportional hazards regression models and generalized linear models with inverse probability weights were used to estimate weighted hazard ratios (HRs) and standardized mean differences, respectively, with 95% CIs. Results The ADHD diagnosis sample comprised 10 167 children (mean [SD] maternal age, 30.2 [4.6] years; 5231 boys [51.5%]), and the ADHD symptoms sample comprised 4367 children (mean [SD] maternal age, 30.6 [4.4] years; 2191 boys [50.2%]). Children were followed up for a mean (SD) of 10.6 (2.2) years. Children with prenatal triptan exposure had no increased risk of ADHD diagnosis compared with unexposed children whose mothers had migraine during pregnancy (weighted HR, 1.16; 95% CI, 0.78-1.74) and compared with unexposed children whose mothers had migraine only before pregnancy (weighted HR, 1.28; 95% CI, 0.84-1.94). There were no differences in ADHD symptom scores between exposed and unexposed children. Conclusions and Relevance The findings of this study suggest that there is no increased risk of ADHD among offspring associated with prenatal exposure to triptans.

• Sundbakk, Lene Maria; Gran, Jon Michael; Wood, Mollie; Handal, Marte; Skurtveit, Svetlana Ondrasova & Nordeng, Hedvig Marie Egeland (2022). Association of Prenatal Exposure to Benzodiazepines and Z-Hypnotics With Risk of Attention-Deficit/Hyperactivity Disorder in Childhood. JAMA Network Open. 5(12), s. 1–15. doi: 10.1001/jamanetworkopen.2022.46889. Fulltekst i vitenarkiv Vis sammendrag

  Importance Evidence is limited regarding the safety of prenatal benzodiazepine and z-hypnotic exposure and its association with long-term neurodevelopment in childhood. Objective To quantify the associations of the timing and number of intervals of prenatal exposure to benzodiazepines and/or z-hypnotics with the risk of attention-deficit/hyperactivity disorder (ADHD) in childhood. Design, Setting, and Participants This cohort study used data from the 1999 to 2008 population-based Norwegian Mother, Father and Child Cohort Study, which are linked to the Medical Birth Registry of Norway, Norwegian Patient Registry, and Norwegian Prescription Database. Two populations of participants were created: a full sample and a mental health sample. The full sample included mothers and their live-born singletons, whereas the mental health sample was restricted to offspring of mothers who reported anxiety, depression, or sleeping problems during pregnancy or 6 months before pregnancy. Data were analyzed from September 2021 to February 2022. Exposures Maternal self-report of benzodiazepine and/or z-hypnotic use during pregnancy was grouped into early pregnancy exposure and middle and/or late pregnancy exposure for analysis of the association with timing of exposure, and number of 4-week intervals of exposure was classified (single [1] vs multiple [≥2]) for analysis of the association with number of exposed intervals. Main Outcome and Measures The outcome was ADHD, defined as time to ADHD diagnosis or filled prescription for ADHD medication. To control for confounding, inverse probability of treatment–weighted Cox proportional hazards regression models were used. Hazard ratios and 95% CIs were estimated. The weights were derived from propensity score modeling of the probability of benzodiazepine and/or z-hypnotic exposure as a function of potential confounders between the exposure and the outcome, including maternal symptoms of depression and anxiety. Results The full sample comprised 82 201 pregnancies, and the mental health sample included 19 585 pregnancies. In total, 681 offspring (0.8%) in the full sample and 468 offspring (2.4%) in the mental health sample were prenatally exposed to benzodiazepines and/or z-hypnotics. After weighting, exposure in early (hazard ratio, 0.74; 95% CI, 0.39-1.94) and middle and/or late (hazard ratio, 0.76; 95% CI, 0.35-1.61) pregnancy was not associated with increased risk of childhood ADHD. There was no evidence of substantial association between the number of exposed intervals during pregnancy and childhood ADHD. Conclusions and Relevance Results of this study suggest that there may be no increased risk of childhood ADHD associated with prenatal exposure to benzodiazepines and/or z-hypnotics, regardless of timing of exposure and number of exposed intervals. However, these findings should be interpreted with caution due to low study power.

• Tauqeer, Fatima; Wood, Mollie; Andersen, Sarah Hjorth; Lupattelli, Angela & Nordeng, Hedvig (2021). Perinatal use of triptans and other drugs for migraine - A nationwide drug utilization study. PLOS ONE. 16(8). doi: 10.1371/journal.pone.0256214. Fulltekst i vitenarkiv Vis sammendrag

  Objective To characterize nationwide utilization patterns of migraine pharmacotherapy before, during, and after pregnancy in women with triptan use. Methods Population-based data were obtained by linking the Medical Birth Registry of Norway and the Norwegian Prescription Database from 2006 to 2017. We included 22,940 pregnancies among 19,669 women with at least one filled triptan prescription, a proxy for migraine, in the year before pregnancy or during pregnancy. The population was classified into four groups: i) continuers; ii) discontinuers; iii) initiators, and vi) post-partum re-initiators. Participant characteristics and prescription fills for other drugs such as analgesics, antinauseants, and preventive drugs among the groups were examined, along with an array of triptan utilization parameters. Results In total, 20.0% of the women were classified as triptan continuers, 54.1% as discontinuers, 8.0% as initiators, and 17.6% as re-initiators. Extended use of triptans (�15 daily drug doses/month) occurred among 6.9% of the continuers in the first trimester. The top 10% of triptan continuers and initiators accounted for 41% (95% CI: 39.2% - 42.5%) and 33% (95% CI: 30.3% - 35.8%) of the triptan volume, respectively. Triptan continuers and initiators had similar patterns of acute co-medication during pregnancy, but use of preventive drugs was more common among the continuers before, during, and after pregnancy. Conclusion Among women using triptans before and during pregnancy, one in four continued triptan treatment during pregnancy, and extended triptan use was relatively low. Triptan discontinuation during and in the year after pregnancy was common. Use of other acute migraine treatments was higher among both continuers and initiators of triptans. Women using preventive migraine treatment were most commonly triptan continuers and re-initiators after pregnancy. Prescribing to and counseling of women with migraine should be tailored to the condition severity and their information needs to promote optimal migraine management in pregnancy. Introduction

• Wood, Mollie; Lupattelli, Angela; Palmsten, Kristin; Bandoli, Gretchen; Hurault-Delarue, Caroline & Damase-Michel, Christine [Vis alle 9 forfattere av denne artikkelen] (2021). Longitudinal Methods for Modeling Exposures in Pharmacoepidemiologic Studies in Pregnancy. Epidemiologic Reviews. ISSN 0193-936X. 43(1), s. 130–146. doi: 10.1093/epirev/mxab002. Fulltekst i vitenarkiv Vis sammendrag

  In many perinatal pharmacoepidemiologic studies, exposure to a medication is classified as “ever exposed” versus “never exposed” within each trimester or even over the entire pregnancy. This approach is often far from real-world exposure patterns, may lead to exposure misclassification, and does not to incorporate important aspects such as dosage, timing of exposure, and treatment duration. Alternative exposure modeling methods can better summarize complex, individual-level medication use trajectories or time-varying exposures from information on medication dosage, gestational timing of use, and frequency of use. We provide an overview of commonly used methods for more refined definitions of real-world exposure to medication use during pregnancy, focusing on the major strengths and limitations of the techniques, including the potential for method-specific biases. Unsupervised clustering methods, including k-means clustering, group-based trajectory models, and hierarchical cluster analysis, are of interest because they enable visual examination of medication use trajectories over time in pregnancy and complex individual-level exposures, as well as providing insight into comedication and drug-switching patterns. Analytical techniques for time-varying exposure methods, such as extended Cox models and Robins’ generalized methods, are useful tools when medication exposure is not static during pregnancy. We propose that where appropriate, combining unsupervised clustering techniques with causal modeling approaches may be a powerful approach to understanding medication safety in pregnancy, and this framework can also be applied in other areas of epidemiology.

• Wood, Mollie (2021). Prenatal antidepressant exposure and neurodevelopmental problems in children: to get the right answer, we must ask the right question. Pediatric Research. ISSN 0031-3998. doi: 10.1038/s41390-020-01348-8. Fulltekst i vitenarkiv
• Harris, Gerd Marie Eskerud; Wood, Mollie & Nordeng, Hedvig Marie Egeland (2020). Modeling exposures of medications used episodically during pregnancy: Triptans as a motivating example. Pharmacoepidemiology and Drug Safety. ISSN 1053-8569. 29(9), s. 1111–1119. doi: 10.1002/pds.5089. Fulltekst i vitenarkiv Vis sammendrag

  Purpose To assess the validity of dispensed prescription to classify exposure to medications used episodically during pregnancy, and to explore individual trajectories of episodic medication use across pregnancy, using triptans for migraine as the motivating example. Methods We compared self‐reported triptan use during pregnancy in The Norwegian Mother, Father and Child Cohort Study (MoBa) to dispensed prescriptions in The Norwegian Prescription Database and calculated Cohen's kappa coefficient (κ), sensitivity, specificity and predictive values using MoBa as reference standard. We used group‐based trajectory modeling to estimate exposure trajectories in MoBa according to probability of triptan use across pregnancy. Results We identified 6051 pregnancies where mothers filled at least one triptan prescription or reported migraine or triptan use in the 6 months before or during pregnancy. Sensitivity of prescribed triptans during pregnancy was low (39.1%), but specificity was quite high (95.4%). Agreement between the two data sources was fair (κ 0.36). We identified three trajectory groups in MoBa including constant‐high, decreasing‐medium and decreasing‐low probability of triptan use across pregnancy. Conclusions Using dispensed prescriptions rather than self‐report to classify exposure to triptans during pregnancy is likely to result in substantial under‐estimation of exposure. In this study, traditional definitions of ever‐exposed vs never‐exposed failed to capture variations in drug utilization during pregnancy.

• Mahic, Milada; Hernandez-Diaz, Sonia; Wood, Mollie; Kieler, Helle; Odsbu, Ingvild & Nørgaard, Mette [Vis alle 11 forfattere av denne artikkelen] (2020). In utero opioid exposure and risk of infections in childhood: A multinational Nordic cohort study. Pharmacoepidemiology and Drug Safety. ISSN 1053-8569. 29(12), s. 1596–1604. doi: 10.1002/pds.5088. Fulltekst i vitenarkiv
• Andersen, Sarah Hjorth; Wood, Mollie; Tauqeer, Fatima & Nordeng, Hedvig Marie Egeland (2020). Fertility treatment and oral contraceptive discontinuation for identification of pregnancy planning in routinely collected health data – an application to analgesic and antibiotic utilisation. BMC Pregnancy and Childbirth. 20. doi: 10.1186/s12884-020-03435-4. Fulltekst i vitenarkiv Vis sammendrag

  Background Women with unplanned pregnancies use folic acid less frequently, and more often use potentially teratogenic medications in the first trimester. Yet most studies based on routinely collected data lack information on pregnancy planning. Further, only pregnancies proceeding beyond a certain gestational age appear in routinely collected data, creating the possibility for collider-stratification bias. If pregnancy intention could be identified, pregnancies could be ascertained earlier. This study aimed to investigate fertility treatment and discontinuation of oral contraception (OC) as proxies for pregnancy planning by describing variations in patterns of prescription fills for antibiotics and analgesics during the peri-pregnancy period by these proxies of pregnancy intention. Methods Fertility treatment with clomiphene and discontinuation of OC were identified in the Norwegian Prescription Database (NorPD) and linked with data from the Medical Birth Registry of Norway for the years 2006 to 2017. Filled prescriptions for antibiotics and analgesics from NorPD were displayed for women on fertility treatment, women who discontinued OC before pregnancy, and women who discontinued during pregnancy. Results Of 172,585 included pregnancies, fertility treatment was identified in 19,449, and OC discontinuation before or during pregnancy in 153,136. Women who discontinued OC during pregnancy were less likely to use preconception folic acid (25.4%) than women who discontinued before pregnancy (32.9%), and women on fertility treatment (51.0%). Proportions of first trimester prescription fills were 4.9% (analgesics) and 12.8% (antibiotics) for women who discontinued OC during pregnancy, compared to 4.0 and 11.4% in women who discontinued OC before pregnancy, and 4.7 and 11.0% in women on fertility treatment. Conclusions There were no substantial differences in patterns of prescription fills for analgesics and antibiotics before or during pregnancy by fertility treatment and OC discontinuation. This suggests that there were few differences in medication use between women with planned and unplanned pregnancies, or that fertility treatment and timing of OC discontinuation from routinely collected health data cannot stand alone in the identification of unplanned pregnancies. A narrower definition of OC discontinuation during pregnancy seemed to be a better proxy, but this should be confirmed in other studies.

• Cohen, Jacqueline Mallory; Wood, Mollie; Hernandez-Diaz, Sonia; Ystrøm, Eivind & Nordeng, Hedvig Marie Egeland (2019). Paternal antidepressant use as a negative control for maternal use: assessing familial confounding on gestational length and anxiety traits in offspring. International Journal of Epidemiology. ISSN 0300-5771. 48(5), s. 1665–1672. doi: 10.1093/ije/dyz170. Fulltekst i vitenarkiv Vis sammendrag

  Background Maternal antidepressant use in pregnancy has been associated with both shorter gestational length and child anxiety. We employed paternal antidepressant use as a negative-control exposure to indirectly assess whether confounding by genetic or shared familial environmental factors associated with depression may explain these associations. Methods The study sample came from the population-based Norwegian Mother and Child Cohort Study (MoBa) that recruited participants from 1999 to 2008. We included 70 959 families where the father completed a questionnaire about medication use in the 6 months prior to pregnancy. In 42 511 infants who completed the 3-year follow-up, we computed Z-scores for the anxiety domain of the Child Behavior Checklist. We used linear and logistic regression to assess the association between paternal antidepressant use, gestational age at birth and child anxiety. Results Antidepressants were used by 1.1% (n = 755) of fathers. Paternal antidepressant use was not associated with gestational age at birth [β = 0.63 days, 95% confidence interval (CI) –1.56, 0.31] whereas it was positively associated with a child anxiety symptom Z-score and high anxiety symptoms (odds ratio 1.33, 95% CI 0.90, 1.97) in unadjusted analyses. This association was attenuated when controlling for maternal and paternal history of depression and other measured factors (odds ratio 1.14, 95% CI 0.76, 1.69). Conclusions These results support the suggested effect of maternal use of antidepressants in pregnancy on shorter gestation; however, they suggest familial confounding could explain the association between maternal use of antidepressants and anxiety traits in the offspring.

• Lupattelli, Angela; Wood, Mollie & Nordeng, Hedvig Marie Egeland (2019). Analyzing Missing Data in Perinatal Pharmacoepidemiology Research: Methodological Considerations to Limit the Risk of Bias. Clinical Therapeutics. ISSN 0149-2918. 41(12), s. 2477–2487. doi: 10.1016/j.clinthera.2019.11.003. Fulltekst i vitenarkiv Vis sammendrag

  Pharmacoepidemiological studies on the safety of medication during pregnancy are all susceptible to missing data (ie, data that should have been recorded but for some reason were not). Missing data are ubiquitous, irrespective of the data source used. Bias can arise when incomplete data on confounders, outcome measures, pregnancy duration, or even cohort selection criteria are used to estimate prenatal exposure effects that would be obtained from the fully observed data, if these were available for each mother–child dyad. This commentary describes general missing data mechanisms and methods, and illustrates how missing data were handled in recent medication in pregnancy research, according to the utilized data source. We further present one applied example on missing data analysis within MoBa (the Norwegian Mother, Father and Child Cohort Study), and finally illustrate how the causal diagram framework can be helpful in assessing risk of bias due to missing data in perinatal pharmacoepidemiology research. We recommend that applied researchers limit missing data during data collection, carefully diagnose missingness, apply strategies for missing data mitigation under different assumptions, and finally include evaluations of robustness results under these assumptions. Following this set of recommendations can aid future perinatal pharmacoepidemiology research in avoiding the problems that result from failure to consider this important source of bias.

• Trønnes, Johanne Naper; Wood, Mollie; Lupattelli, Angela; Ystrøm, Eivind & Nordeng, Hedvig Marie Egeland (2019). Prenatal paracetamol exposure and neurodevelopmental outcomes in preschool-aged children. Paediatric and Perinatal Epidemiology. ISSN 0269-5022. 34(3), s. 247–256. doi: 10.1111/ppe.12568. Fulltekst i vitenarkiv Vis sammendrag

  Background Recent studies have suggested an association between prenatal paracetamol exposure and adverse neurodevelopmental outcomes in children. However, these findings may be confounded by unmeasured factors related to maternal use of paracetamol and child outcomes. Objective To examine the association between duration and timing of prenatal paracetamol exposure on parent‐reported communication skills, behaviour, and temperament in preschool‐aged children, with focus on the role of unmeasured confounding. Methods We used data from the Norwegian Mother and Child Cohort Study. Linear and generalised linear models with inverse probability weights and robust standard errors were used to quantify the association between prenatal paracetamol exposure and continuous and categorical outcomes. Results Of the 32 934 children included in our study, 8374 (25.4%), 4961 (15.1%), and 1791 (5.4%) were prenatally exposed to paracetamol in one, two, and three trimesters, respectively. Children exposed to paracetamol in two trimesters scored lower on shyness compared with unexposed children (β −0.62, 95% confidence interval [CI] −1.05, −0.19). Children exposed to paracetamol in three trimesters had a moderate increased risk of internalising behaviour problems (relative risk (RR) 1.36, 95% CI 1.02, 1.80) and borderline externalising behaviour problems (RR 1.22, 95% CI 0.93, 1.60) compared with unexposed children. Children exposed to paracetamol in 2nd/3rd trimester scored lower on shyness (β −0.32, 95% CI −0.66, 0.02) compared with unexposed children. Sensitivity analyses indicated that unmeasured confounders play an important role and may potentially bias the effect estimates away from the null. Conclusions Timing of exposure and short‐term use of paracetamol during pregnancy do not seem to pose any substantial risk of the outcomes examined. Although we found an association between paracetamol use in multiple trimesters and lower shyness and greater internalising behaviour in preschool‐aged children, we cannot rule out chance or unmeasured confounding as possible explanations for these findings.

• Lund, Ingunn Olea; Eilertsen, Espen Moen; Gjerde, Line C.; Røysamb, Espen; Wood, Mollie & Reichborn-Kjennerud, Ted [Vis alle 7 forfattere av denne artikkelen] (2019). Is the association between maternal alcohol consumption in pregnancy and pre-school child behavioural and emotional problems causal? Multiple approaches for controlling unmeasured confounding. Addiction. ISSN 0965-2140. 114(6), s. 1004–1014. doi: 10.1111/add.14573. Fulltekst i vitenarkiv Vis sammendrag

  Background and aims Hazardous drinking (i.e. alcohol consumption that places drinkers at risk for adverse health outcomes) during pregnancy is associated with adverse child outcomes. To address whether the associations are causal, we aimed to estimate the effect of maternal hazardous drinking during the first trimester on offspring emotional and behavioural problems throughout the pre‐school age. We adjusted for: (1) measured confounding (e.g. smoking), (2) familial risk factors by sibling control design and (3) non‐shared environmental risk factors by using hazardous drinking the 3 months before pregnancy as an instrumental variable. Design Prospective cohort study. Participants were recruited between 1999 and 2009 at ultrasound examination offered to all pregnant women in Norway. Data were collected during the 17th and the 30th weeks of gestation, and when the children were aged 1.5, 3 and 5 years. Setting Norway, 1999–2015. Participants The sample consisted of 14 639 mothers with 25 744 offspring siblings from the Norwegian Mother and Child Cohort Study. Measurements Respondents self‐reported on: alcohol consumption, children's emotional problems (i.e. emotional reactive, anxiety/depression, somatic complaints) and children's behavioural problems (i.e. attention and aggressive behaviour) throughout pre‐school age. We used longitudinal latent growth curve models to estimate the effect of maternal drinking during the first trimester on offspring emotional and behavioural problems. Findings Most associations were strongly reduced after controlling for both familial and measured environmental risk factors. After adjustment, exposed children were more emotionally reactive [β = 2.33; 95% confidence interval (CI) = 0.13–4.53] and had more somatic complaints (β = 1.93; 95% CI = 0.09–3.77) at age 3, but not at age 5. Exposed children were less aggressive than unexposed siblings at age 5 (β = −2.27; 95% CI = –4.02 to –0.52). Conclusions Children exposed to their mothers’ hazardous drinking during the first trimester appear to be more emotionally reactive and have more somatic complaints at age 3, but not at age 5, and are less aggressive at age 5 compared with unexposed siblings.

• Sundbakk, Lene Maria; Wood, Mollie; Gran, Jon Michael & Nordeng, Hedvig Marie Egeland (2019). Impact of prenatal exposure to benzodiazepines and z-hypnotics on behavioral problems at 5 years of age: A study from the Norwegian Mother and Child Cohort Study. PLOS ONE. 14(6). doi: 10.1371/journal.pone.0217830. Fulltekst i vitenarkiv Vis sammendrag

  Many women experience anxiety or sleep disorders during pregnancy and require pharmacological treatment with benzodiazepines (BZDs) or z-hypnotics. Limited information is currently available on how prenatal exposure to these medications affects behavioral problems in children over the long term. Therefore, from a public health perspective, this issue is highly important. The present study aimed to determine whether prenatal exposure to BZDs and z-hypnotics affected externalizing and internalizing behavior problems in children at age 5 years. This study was based on The Norwegian Mother and Child Cohort Study and The Medical Birth Registry of Norway. The final study population included data for 36 401 children, from questionnaires completed by the mothers throughout the 5-year follow up. Children’s behaviors were measured at age 5, based on parental responses to The Child Behavior Checklist. Children T-scores of 63 or above were considered to indicate clinically relevant behavior problems. We applied inverse probability of treatment weighting (IPTW) and log-binomial regression models to estimate risk ratios (RRs) and bootstrapped 95% confidence intervals (CIs) with censoring weights to account for loss during follow-up. Several sensitivity analyses were performed to assess the robustness of the main results. The final sample included 273 (0.75%) children that were exposed to BZDs and/or z-hypnotics during pregnancy. The main, IPTW and censoring weighted analyses showed that prenatal exposure to BZD and/or z-hypnotics increased the risks of internalizing behavioral problems (RR: 1.35, 95% CI: 0.73–2.49) and externalizing behavioral problems (RR: 1.51, 95% CI: 0.86–2.64). However, based on sensitivity analyses, we concluded that the risks of displaying externalizing and internalizing problems at 5 years of age did not significantly increase after prenatal exposure to BZDs and/or z-hypnotics. Instead, the sensitivity analyses suggested that residual confounding and selection bias might explain the increased risks observed in the main analyses.

• Cohen, Jacqueline M.; Wood, Mollie; Hernandez-Diaz, Sonia & Nordeng, Hedvig Marie Egeland (2018). Agreement between paternal self-reported medication use and records from a national prescription database. Pharmacoepidemiology and Drug Safety. ISSN 1053-8569. 27(4), s. 413–421. doi: 10.1002/pds.4411. Fulltekst i vitenarkiv Vis sammendrag

  PurposeFather's medication use is of interest in fertility studies and as negative control exposures in pregnancy medication safety studies. We sought to compare self-report to prescription records to understand how reliably each of these sources of information may be used. MethodsWe compared self-reported medication use in the 6 months prior to pregnancy from fathers participating in the Norwegian Mother and Child Cohort Study to records of dispensed prescriptions from the Norwegian Prescription Database that overlapped in time. Medications from 3 main categories were assessed: prescription medications used chronically, prescription medications used episodically, and over-the-counter/prescription medications (predominantly obtained without prescription). We calculated agreement between self-report and dispensing records using Cohen's kappa statistic. ResultsWe included 42848 pregnancies with the father's prescription data available for the 9 months before pregnancy. Prescription medications used chronically including antiepileptics, antipsychotics, and antidepressants showed substantial agreement between self-report and prescription records: kappa statistics 0.87, 0.63, and 0.74, respectively. Prescription medications used episodically like anti-infectives, opioids, anxiolytics, and hypnotics and sedatives showed worse agreement: kappa 0.19, 0.32, 0.40, 0.32. Over-the-counter/prescription medications like paracetamol and nonsteroidal anti-inflammatory drugs had slight agreement: kappa 0.02 and 0.20. ConclusionsThere is good agreement between paternal self-report and prescription data for prescribed medications used chronically and substantially less for medications used episodically. Suboptimal agreement for episodic medications suggests poor recall (for questionnaires) or false positives due to noncompliance (prescription data). Not surprisingly, use of medications available both with and without a prescription is not well captured using prescription databases alone.

• Lupattelli, Angela; Wood, Mollie; Ystrøm, Eivind; Skurtveit, Svetlana; Handal, Marte & Nordeng, Hedvig Marie Egeland (2018). Effect of Time-Dependent Selective Serotonin Reuptake Inhibitor Antidepressants During Pregnancy on Behavioral, Emotional, and Social Development in Preschool-Aged Children. Journal of the American Academy of Child and Adolescent Psychiatry. ISSN 0890-8567. 57(3), s. 200–208. doi: 10.1016/j.jaac.2017.12.010. Fulltekst i vitenarkiv
• Harris, Gerd Marie Eskerud; Wood, Mollie; Ystrøm, Eivind & Nordeng, Hedvig Marie Egeland (2018). Prenatal triptan exposure and neurodevelopmental outcomes in 5-year-old children: Follow-up from the Norwegian Mother and Child Cohort Study. Paediatric and Perinatal Epidemiology. ISSN 0269-5022. 32(3), s. 247–255. doi: 10.1111/ppe.12461. Fulltekst i vitenarkiv Vis sammendrag

  Background Triptans are commonly used to treat migraine headaches, but data on the long‐term safety of these medications during pregnancy are sparse. Triptans have a biologically plausible mechanism for effects on the fetal brain through binding to 5‐HT1‐receptors, and previous studies show increased risks of externalising behaviour problems in toddlers exposed to triptans during pregnancy. Methods We included 3784 children in the Norwegian Mother and Child Cohort Study, whose mothers returned the 5‐year‐questionnaire and reported a history of migraine or triptan use; 353 (9.3%) mothers reported use of triptans during pregnancy, 1509 (39.9%) reported migraine during pregnancy but no triptan use, and 1922 (50.8%) had migraine prior to pregnancy only. We used linear and log‐binomial models with inverse probability weights to examine the association between prenatal triptan exposure and internalising and externalising behaviour, communication, and temperament in 5‐year‐old children. Results Triptan‐exposed children scored higher on the sociability trait than unexposed children of mothers with migraine (β 1.66, 95% confidence interval [0.30, 3.02]). We found no other differences in temperament, or increased risk of behaviour or communication problems. Conclusions Contrary to results from previous studies in younger children, we found no increased risk of externalising behaviour problems in 5‐year‐old children exposed to triptans in fetal life. Triptan‐exposed children did have slightly more sociable temperaments, but the clinical meaning of this finding is uncertain.

• Wood, Mollie; Chrysanthopoulou, Stavroula; Nordeng, Hedvig Marie Egeland & Lapane, Kate L. (2018). The impact of nondifferential exposure misclassification on the performance of propensity scores for continuous and binary outcomes: a simulation study. Medical Care. ISSN 0025-7079. 56(8), s. e46–e53. doi: 10.1097/MLR.0000000000000800. Fulltekst i vitenarkiv Vis sammendrag

  Purpose: To investigate the ability of the propensity score (PS) to reduce confounding bias in the presence of nondifferential misclassification of treatment, using simulations. Methods: Using an example from the pregnancy medication safety literature, we carried out simulations to quantify the effect of nondifferential misclassification of treatment under varying scenarios of sensitivity and specificity, exposure prevalence (10%, 50%), outcome type (continuous and binary), true outcome (null and increased risk), confounding direction, and different PS applications (matching, stratification, weighting, regression), and obtained measures of bias and 95% confidence interval coverage. Results: All methods were subject to substantial bias toward the null due to nondifferential exposure misclassification (range: 0%–47% for 50% exposure prevalence and 0%–80% for 10% exposure prevalence), particularly if specificity was low (< 97%). PS stratification produced the least biased effect estimates. We observed that the impact of sensitivity and specificity on the bias and coverage for each adjustment method is strongly related to prevalence of exposure: as exposure prevalence decreases and/or outcomes are continuous rather than categorical, the effect of misclassification is magnified, producing larger biases and loss of coverage of 95% confidence intervals. PS matching resulted in unpredictably biased effect estimates. Conclusions: The results of this study underline the importance of assessing exposure misclassification in observational studies in the context of PS methods. Although PS methods reduce confounding bias, bias owing to nondifferential misclassification is of potentially greater concern.

• Svendsen, Kristian; Wood, Mollie; Olsson, Erika & Nordeng, Hedvig Marie Egeland (2017). Reported time to onset of neurological adverse drug reactions among different age and gender groups using metoclopramide: an analysis of the global database Vigibase®. European Journal of Clinical Pharmacology. ISSN 0031-6970. doi: 10.1007/s00228-017-2407-z. Fulltekst i vitenarkiv
• Andrade, Susan; Berard, Anick; Nordeng, Hedvig Marie Egeland; Wood, Mollie; Gelder, Marlene van & Toh, Sengwee (2017). Administrative Claims Data Versus Augmented Pregnancy Data for the Study of Pharmaceutical Treatments in Pregnancy. Current Epidemiology Reports. ISSN 2196-2995. 4(2), s. 106–116. doi: 10.1007/s40471-017-0104-1. Fulltekst i vitenarkiv Vis sammendrag

  Purpose of Review: Administrative claims databases, which collect reimbursement-related information generated from healthcare encounters, are increasingly used to evaluate medication safety in pregnancy. We reviewed the strengths and limitations of claims-only databases and how other data sources may be used to improve the accuracy and completeness of information critical for studying medication safety in pregnancy. Recent Findings: Research on medication safety in pregnancy requires information on pregnancy episodes, mother-infant linkage, medication exposure, gestational age, maternal and birth outcomes, confounding factors, and (in some studies) long-term follow-up data. Claims data reliably identifies live births and possibly other pregnancies. It allows mother-infant linkage and has prospectively collected prescription medication information. Its diagnosis and procedure information allows estimation of gestational age. It captures maternal medical conditions but generally has incomplete data on reproductive and lifestyle factors. It has information on certain, typically short-term maternal and infant outcomes that may require chart review confirmation. Other data sources including electronic health records and birth registries can augment claims data or be analyzed alone. Interviews, surveys, or biological samples provide additional information. Nationwide and regional birth and pregnancy registries, such as those in several European and North American countries, generally contain more complete information essential for pregnancy research compared to claims-only databases. Summary: Claims data offers several advantages in medication safety in pregnancy research. Its limitations can be partially addressed by linking it with other data sources or supplementing with primary data collection. Rigorous assessment of data quality and completeness is recommended regardless of data sources.

• Harris, Gerd Marie Eskerud; Wood, Mollie; Eberhard-Gran, Malin; LUNDQVIST, CHRISTOFER & Nordeng, Hedvig Marie Egeland (2017). Patterns and predictors of analgesic use in pregnancy: a longitudinal drug utilization study with special focus on women with migraine. BMC Pregnancy and Childbirth. 17. doi: 10.1186/s12884-017-1399-0. Fulltekst i vitenarkiv Vis sammendrag

  Background Few studies have investigated the drug utilization patterns and factors predicting drug use in pregnant women with migraine. This longitudinal drug utilization study aimed to describe patterns of analgesic use in a sample of Norwegian pregnant women according to their migraine history, and to identify predictors for analgesic use among these women. Methods Pregnant women giving birth at Akershus University Hospital between 2008 and 2010 were recruited at ultrasound examination in gestational week 17. Data were collected by questionnaires in gestational weeks 17 and 32, and at 8 weeks postpartum, and linked to birth records. Women were grouped into four categories according to migraine history: no migraine history, previous migraine history, recent migraine history (within 1 year prior to pregnancy) and migraine in pregnancy. Patterns of use of analgesics were analyzed descriptively. Multivariable logistic regression was used to identify factors predicting analgesic use. Results Out of 1981 women, 5.0% reported having migraine in pregnancy, 13.2% had a recent history of migraine, 11.5% had a previous history of migraine, and 68.8% reported no history of migraine. Analgesic use declined during pregnancy. Many women switched from triptans and non-steroidal anti-inflammatory drugs to paracetamol, which constituted most of the analgesic use. Factors associated with analgesic use included recent migraine history (OR 1.6, 95% CI 1.2–2.2), more severe headache intensity (OR 1.3, 95% CI 1.3–1.4), smoking (OR 1.9, 95% CI 1.1–3.3) and multiparity (OR 1.4, 95% CI 1.1–1.7). Conclusions Women with migraine stop or switch medications during pregnancy. Analgesic use in pregnancy is affected by migraine characteristics and intensity, and also by socio-demographic factors. Clinicians should bear this in mind when giving advice on adequate management of migraine in pregnancy and safe analgesic use.

• Lupattelli, Angela; Wood, Mollie; Lapane, Kate L; Spigset, Olav & Nordeng, Hedvig Marie Egeland (2017). Risk of preeclampsia after gestational exposure to selective serotonin reuptake inhibitors and other antidepressants: A study from The Norwegian Mother and Child Cohort Study. Pharmacoepidemiology and Drug Safety. ISSN 1053-8569. 26(10), s. 1266–1276. doi: 10.1002/pds.4286. Fulltekst i vitenarkiv Vis sammendrag

  Purpose To describe the risk of early- and late-onset preeclampsia across pregnancies exposed to antidepressants and to evaluate the impact of timing and length of gestational exposure to antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs), on preeclampsia. Methods The Norwegian Mother and Child Cohort, a prospective population-based study, and the Medical Birth Registry of Norway provided information on antidepressant exposure, depression, and anxiety symptoms in pregnancy, preeclampsia diagnoses, and important covariates. Within a pregnancy cohort of depressed women, we compared the risk of late-onset preeclampsia between SSRI-exposed and nonmedicated pregnancies using marginal structural models (weighted) and modified Poisson regression models. Results Of the 5887 pregnancies included, 11.1% were exposed at any time before week 34 to SSRIs, 1.3% to serotonin-norepinephrine reuptake inhibitors, 0.4% to tricyclic antidepressants, and 0.5% to other antidepressants. The risks of early- and late-onset preeclampsia by exposure status in pregnancy were 0.3% and 3.6% (nonmedicated), 0.4% and 3.7% (SSRIs), 1.5% and 4.1% (serotonin-norepinephrine reuptake inhibitors), and 7.1% and 10.0% (tricyclic antidepressants). Compared with nonmedicated pregnancies, SSRI-exposed in mid and late gestation had adjusted relative risks for late-onset mild preeclampsia of 0.76 (95% confidence interval, 0.38-1.53) and 1.56 (0.71-3.44) (weighted models), respectively. There was no association between SSRI exposure in pregnancy and severe late-onset preeclampsia. Conclusions We have provided evidence that SSRI use in early and midpregnancy does not substantially increase the risk of late-onset preeclampsia.

• Wood, Mollie; Lapane, Kate L; Gelder, Marleen MHJ van; Rai, Dheeraj & Nordeng, Hedvig Marie Egeland (2017). Making fair comparisons in pregnancy medication safety studies: An overview of advanced methods for confounding control. Pharmacoepidemiology and Drug Safety. ISSN 1053-8569. 27(2), s. 140–147. doi: 10.1002/pds.4336. Fulltekst i vitenarkiv Vis sammendrag

  Understanding the safety of medication use during pregnancy relies on observational studies: However, confounding in observational studies poses a threat to the validity of estimates obtained from observational data. Newer methods, such as marginal structural models and propensity calibration, have emerged to deal with complex confounding problems, but these methods have seen limited uptake in the pregnancy medication literature. In this article, we provide an overview of newer advanced methods for confounding control and show how these methods are relevant for pregnancy medication safety studies.

• Salvatore, Stefania; Domanska, Diana Ewa; Wood, Mollie; Nordeng, Hedvig Marie Egeland & Sandve, Geir Kjetil (2017). Complex patterns of concomitant medication use: A study among Norwegian women using paracetamol during pregnancy. PLOS ONE. 12(12). doi: 10.1371/journal.pone.0190101. Fulltekst i vitenarkiv Vis sammendrag

  Background: Studies on medication safety in pregnancy often rely on an oversimplification of medication use into exposed or non-exposed, without considering intensity and timing of use in pregnancy, or concomitant medication use. This study uses paracetamol in pregnancy as the motivating example to introduce a method of clustering medication exposures longitudinally throughout pregnancy. The aim of this study was to use hierarchical cluster analysis (HCA) to better identify clusters of medication exposure throughout pregnancy. Methods: Data from the Norwegian Mother and Child Cohort Study was used to identify subclasses of women using paracetamol during pregnancy. HCA with customized distance measure was used to identify clusters of medication exposures in pregnancy among children at 18 months. Results: The pregnancies in the study (N = 9 778) were grouped in 5 different clusters depending on their medication exposure profile throughout pregnancy. Conclusion: Using HCA, we identified and described profiles of women exposed to different medications in combination with paracetamol during pregnancy. Identifying these clusters allows researchers to define exposure in ways that better reflects real-world medication usage patterns. This method could be extended to other medications and used as pre-analysis for identifying risks associated with different profiles of exposure.

• Nezvalova-Henriksen, Katerina; Wood, Mollie; Spigset, Olav & Nordeng, Hedvig Marie Egeland (2016). Association of Prenatal Ibuprofen Exposure with Birth Weight and Gestational Age: A Population-Based Sibling Study. PLOS ONE. 11(12). doi: 10.1371/journal.pone.0166971. Fulltekst i vitenarkiv Vis sammendrag

  Objectives Three studies so far have investigated the effect of prenatal non-steroidal anti-inflammatory drug (NSAID) exposure on birth weight and gestational age. The aim in this study was to evaluate the association of prenatal ibuprofen with birth weight and gestational age at birth, using a sibling design in an attempt to adjust for the possibility of familial confounding. Design Using data from the Norwegian Mother and Child Cohort Study (MoBa) and the Medical Birth Registry of Norway (MBRN), we identified 28 597 siblings, of whom 1080 were prenatally exposed to ibuprofen and 26 824 were not exposed to any NSAID. Random and fixed effects models with propensity score adjustment were used to evaluate the effects of ibuprofen exposure on birth weight and gestational age. Results Ibuprofen exposure during the first trimester was associated with a decrease in birth weight of 79 grams (95% confidence interval -133 to -25 grams). In contrast, second and/or third trimester exposure, and duration of exposure had no impact on the effect estimates. We found no association between ibuprofen exposure and gestational age at birth. Conclusions Our results suggest that prenatal exposure to ibuprofen during the first trimester is associated with a slight decrease in birth weight. The association does not seem to be attributable to shared genetics and family environment, and could be explained by either exposure to ibuprofen, or to non-shared confounding between pregnancies.

• Wood, Mollie; Frazier, Jean A; Nordeng, Hedvig Marie Egeland & Lapane, Kate L (2016). Longitudinal changes in neurodevelopmental outcomes between 18 and 36 months in children with prenatal triptan exposure: findings from the Norwegian Mother and Child Cohort Study. BMJ Open. 6(9). doi: 10.1136/bmjopen-2016-011971. Fulltekst i vitenarkiv Vis sammendrag

  Objective This study sought to determine whether changes in neurodevelopmental outcomes between 18 and 36 months of age were associated with prenatal exposure to triptan medications, a class of 5-HT receptor agonists used in the treatment of migraine. Method Using data from the Norwegian Mother and Child Cohort Study, a prospective birth cohort that includes nearly 40% of all pregnancies in Norway from 1999 to 2008, we identified 50 469 mother–child dyads who met inclusion criteria and were present for at least one follow-up assessment at 18 or 36 months postpartum. Neurodevelopment was assessed using the Child Behaviour Checklist, the Emotionality, Activity, and Shyness Questionnaire, and the Ages and Stages Questionnaire. We used generalised estimating equations to evaluate change from 18 to 36 months for children prenatally exposed to triptans, relative to contrast groups, and used marginal structural models with inverse probability of treatment and censoring weights to address time-varying exposure and confounding as well as loss to follow-up. Results Among eligible participants (n=50 469), 1.0% used a triptan during pregnancy, 2.0% used triptans prior to pregnancy only, 8.0% reported migraine without triptan use and 89.0% had no history of migraine. Children with prenatal triptan exposure had greater increases in emotionality (r-RR 2.18, 95% CI 1.03 to 4.53) and activity problems (r-RR 1.70, 95% CI 1.02 to 2.8) compared to children born to mothers who discontinued triptan use prior to pregnancy. Conclusion Prenatal triptan exposure was associated with changes over time in externalising-type behaviours such as emotionality and activity, but not with internalising-type behaviours.

• Wood, Mollie; Frazier, Jean A; Nordeng, Hedvig Marie Egeland & Lapane, Kate L (2016). Prenatal triptan exposure and parent-reported early childhood neurodevelopmental outcomes: an application of propensity score calibration to adjust for unmeasured confounding by migraine severity. Pharmacoepidemiology and Drug Safety. ISSN 1053-8569. 25(5), s. 493–502. doi: 10.1002/pds.3902. Fulltekst i vitenarkiv
• Vlenterie, Richelle; Wood, Mollie; Brandlistuen, Ragnhild Eek; Roeleveld, Nel; Gelder, Marleen M H J van & Nordeng, Hedvig Marie Egeland (2016). Neurodevelopmental problems at 18 months among children exposed to paracetamol in utero: a propensity score matched cohort study. International Journal of Epidemiology. ISSN 0300-5771. 45(6), s. 1998–2008. doi: 10.1093/ije/dyw192. Fulltekst i vitenarkiv
• Wood, Mollie; Lapane, Kate; Frazier, Jean A; Ystrøm, Eivind; Mick, Eric O & Nordeng, Hedvig Marie Egeland (2016). Prenatal Triptan Exposure and Internalising and Externalising Behaviour Problems in 3-Year-Old Children: Results from the Norwegian Mother and Child Cohort Study. Paediatric and Perinatal Epidemiology. ISSN 0269-5022. 30(2), s. 190–200. doi: 10.1111/ppe.12253. Fulltekst i vitenarkiv

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• Harris, Gerd Marie Eskerud; Wood, Mollie; Eberhard-Gran, Malin Marie Cecilia; Lundqvist, Christofer & Nordeng, Hedvig Marie Egeland (2022). Correction to: Patterns and predictors of analgesic use in pregnancy: a longitudinal drug utilization study with special focus on women with migraine (BMC Pregnancy and Childbirth, (2017), 17, 1, (224), 10.1186/s12884-017-1399-0). BMC Pregnancy and Childbirth. 22. doi: 10.1186/s12884-022-04525-1. Fulltekst i vitenarkiv
• Wood, Mollie; Cohen, Jacqueline Mallory; Ystrøm, Eivind; Nordeng, Hedvig Marie Egeland & Hernandez-Diaz, Sonia (2020). Response to: Modelling paternal exposure as a negative control. International Journal of Epidemiology. ISSN 0300-5771. 49(3), s. 1054–1055. doi: 10.1093/ije/dyaa055. Fulltekst i vitenarkiv
• Wood, Mollie; Mahic, Milada; Handal, Marte; Skurtveit, Svetlana; Lund, Ingunn Olea & Hernandez-Diaz, Sonia (2019). Risk of Neonatal Abstinence Syndrome Following Prenatal Exposure to Methadone vs Buprenorphine. Pharmacoepidemiology and Drug Safety. ISSN 1053-8569. doi: 10.1002/pds.4864. Fulltekst i vitenarkiv
• Handal, Marte; Skurtveit, Svetlana; Odsbu, Ingvild; Kieler, Helle; Nørgaard, Mette & Öztürk, Buket [Vis alle 12 forfattere av denne artikkelen] (2019). In utero opioid exposure and risk of ADHD in childhood: A Scandinavian registry study. Pharmacoepidemiology and Drug Safety. ISSN 1053-8569. 28(S2). doi: 10.1002/pds.4864. Fulltekst i vitenarkiv
• Trønnes, Johanne Naper; Wood, Mollie; Lupattelli, Angela; Ystrom, Eivind & Nordeng, Hedvig Marie Egeland (2018). Association of prenatal paracetamol exposure with neurodevelopmental outcomes in 5-year-old children and the role of unmeasured confounding. Fulltekst i vitenarkiv
• Sundbakk, Lene Maria; Wood, Mollie; Gran, Jon Michael & Nordeng, Hedvig Marie Egeland (2018). Does prenatal exposure to benzodiazepines or z-hypnotics increase the risk of behavioral problems at 5 years? Fulltekst i vitenarkiv
• Mahic, Milada; Hernandez-Diaz, Sonia; Wood, Mollie; Odsbu, Ingvild; Nørgaard, Mette & Kieler, Helle [Vis alle 8 forfattere av denne artikkelen] (2018). Infections in children after prenatal exposure to methadone and buprenorphine: Nordic registry study. Pharmacoepidemiology and Drug Safety. ISSN 1053-8569. Fulltekst i vitenarkiv
• Trønnes, Johanne Naper; Wood, Mollie; Lupattelli, Angela; Ystrom, Eivind & Nordeng, Hedvig Marie Egeland (2018). Association of prenatal paracetamol exposure with neurodevelopmental outcomes in 5-year-old children. Fulltekst i vitenarkiv
• Wood, Mollie; Nordeng, Hedvig Marie Egeland; Eilertsen, Espen Moen & Hernandez-Diaz, Sonia (2017). Mediation analysis in sibling studies. Fulltekst i vitenarkiv
• Sundbakk, Lene Maria; Nordeng, Hedvig Marie Egeland; Wood, Mollie & Gran, Jon Michael (2017). Prenatal exposure to benzodiazepines or z-hypnotics and behavioral problems at 5 years of age: A study from the Norwegian Mother and Child cohort study. Fulltekst i vitenarkiv
• Wood, Mollie; Nordeng, Hedvig Marie Egeland; Lapane, Kate L. & Chrysanthopoulou, Stavroula (2017). The impact of differential exposure misclassification on performance of propensity score methods for binary outcome models. Fulltekst i vitenarkiv
• Wood, Mollie; Nordeng, Hedvig Marie Egeland; Lapane, Kate L. & Chrysanthopoulou, Stavroula (2017). The impact of differential exposure misclassification on performance of propensity score methods for binary outcome models. Fulltekst i vitenarkiv
• Lund, Ingunn Olea; Eilertsen, Espen Moen; Gjerde, Line C.; Røysamb, Espen; Wood, Mollie & Reichborn-Kjennerud, Ted [Vis alle 7 forfattere av denne artikkelen] (2017). Prenatal Exposure to Alcohol and Child Internalizing and Externalizing Problems. Fulltekst i vitenarkiv
• Nordeng, Hedvig Marie Egeland; Lupattelli, Angela & Wood, Mollie (2017). Prenatal exposure to antidepressants and increased risk of psychiatric disorders. BMJ. British Medical Journal. ISSN 0959-8146. 358. doi: 10.1136/bmj.j3950. Fulltekst i vitenarkiv
• Wood, Mollie; Nordeng, Hedvig Marie Egeland; Chrysanthopoulou, Stavroula & Lapane, Kate L. (2016). Performance of the propensity score in the presence of nondifferential exposure misclassification: a simulation study. Fulltekst i vitenarkiv
• Wood, Mollie; Nordeng, Hedvig Marie Egeland; Chrysanthopoulou, Stavroula & Lapane, Kate L. (2016). Exposure misclassification and propensity score methods: a simulation study. Fulltekst i vitenarkiv
• Harris, Gerd Marie Eskerud; Wood, Mollie; Eberhard-Gran, Malin & Nordeng, Hedvig Marie Egeland (2016). Patterns and predictors of analgesic use in pregnant women with migraine. Fulltekst i vitenarkiv
• Wood, Mollie (2016). Introduction to causal inference. Fulltekst i vitenarkiv
• Wood, Mollie (2016). Propensity scores in pharmacoepidemiology. Fulltekst i vitenarkiv
• Lupattelli, Angela; Wood, Mollie; Lapane, Kate L.; Spigset, Olav & Nordeng, Hedvig Marie Egeland (2016). Gestational exposure to SSRIs and risk of preeclampsia in pregnancy: a study from the Norwegian Mother and Child cohort study accounting for time-varying severity of depressive and anxiety symptoms. Fulltekst i vitenarkiv
• Nordeng, Hedvig Marie Egeland; Wood, Mollie; Frazier, Jean & Lapane, Kate L. (2015). Prenatal exposure to triptan medications and neurodevelopment in children: an application propensity score calibration methods for unmeasured confounding. Fulltekst i vitenarkiv
• Nordeng, Hedvig Marie Egeland; Wood, Mollie; Frazier, Jean; Lapane, Kate L.; Ystrøm, Eivind & Mick, Eric O. (2015). Prenatal triptan exposure increases externalizing behaviors at three years: results from the Norwegian Mother and Child Cohort Study. Fulltekst i vitenarkiv
• Nezvalova-Henriksen, Katerina; Spigset, Olav; Wood, Mollie & Nordeng, Hedvig Marie Egeland (2015). The effect of prenatal nonsteroidal anti-inflammatory drug (NSAID) exposure on immediate pregnancy outcomes – a sibling controlled cohort study. Fulltekst i vitenarkiv
• Nezvalova-Henriksen, Katerina; Spigset, Olav; Wood, Mollie & Nordeng, Hedvig Marie Egeland (2015). The effect of prenatal nonsteroidal anti-inflammatory drug (NSAID) exposure on immediate pregnancy outcomes – A sibling controlled cohort study. Reproductive Toxicology. ISSN 0890-6238. Fulltekst i vitenarkiv
• Wood, Mollie; Frazier, Jean; Lapane, Kate L. & Nordeng, Hedvig Marie Egeland (2015). Prenatal triptan exposure, communication skills, and psychomotor development in 18 and 36 month old children: results from the Norwegian Mother and Child Cohort Study. Fulltekst i vitenarkiv

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