Making fair comparisons in pregnancy medication safety studies: An overview of advanced methods for confounding control

Association of Prenatal Exposure to Triptans, Alone or Combined With Other Migraine Medications, and Neurodevelopmental Outcomes in Offspring

BACKGROUND AND OBJECTIVES

The long-term reproductive safety of migraine medications remains uncertain. This study sought to examine the effect of different intensities and durations of prenatal exposure to triptans, alone and combined with other preventive migraine medications, on neurodevelopmental disorders (NDDs) in children.

METHODS

This nationwide health registry study in Norway included pregnancies of women with migraine before pregnancy and followed up their children up to 14 years of age. Single and multiple group-based trajectory models and group-based multitrajectory models were applied to cluster triptan exposure alone and combined with preventive antimigraine medications. Child outcomes, based on specialist outpatient and inpatient diagnoses, included autism spectrum and behavioral disorders, learning and intellectual disabilities, speech/language and developmental coordination disorders, and attention-deficit hyperactivity disorders (ADHDs). We fit adjusted and weighted pooled logistic regression models and standardized risk curves using propensity score-based overlap weighting.

RESULTS

We included 26,210 pregnancies of women with migraine; 4,929 and 21,281 were, respectively, nonmedicated and medicated with triptans in the year of prepregnancy. In the latter group, we identified 4 group-based trajectories of triptans alone and combined with preventive medications: discontinuers before (low use) (41.5%, 47.0%), early discontinuers (short-term low use) (31.3%, 28.8%), late discontinuers (moderate use) (21.3%, 9.1%), and late discontinuers (high use) (5.9%, 15.2%). Overall, 1,140 children (4.3%) had a NDD (mean follow-up time: 8 years). Children born to women with any triptan trajectory had a slightly higher risk of NDD compared with children of nonmedicated women (magnitude range of the weighted hazard ratio [wHR]: 1.05-1.16). These risks decreased to the null when discontinuers before (low use) acted as a comparator (magnitude of wHR: 0.94-1.01) or when analyzing speech/language disorders or ADHD (magnitude of wHR: 0.82-1.14). There was a slightly elevated risk of autism disorders with both triptan late discontinuation trajectories (wHR 1.24, 95% CI [0.78-1.97]; wHR 1.30, 95% CI [0.66-2.56]), but the 95% CI crossed the null and the weighted risk difference remained low.

DISCUSSION

Our findings indicate that prenatal exposure to triptans, alone or combined with other migraine medications, does not substantially increase the risk of a broad range of neurodevelopmental outcomes in children up to adolescence.

Agreement Between Parental Self-Reported Antiseizure Medication Use and Dispensed Prescription Records From a National Prescription Database

PURPOSE

Accurate measurement of medication exposure is crucial for studying the safety of antiseizure medications (ASMs) during pregnancy. Pregnancy safety studies of ASMs frequently rely on secondary data from drug prescription registries to assess potential teratogenic effects and impact on fetal development. This study aimed to evaluate the agreement between dispensed prescriptions registered in a national database and self-reported ASM use by parents.

METHODS

The Norwegian Prescription Database (NorPD) was linked to the Norwegian Mother, Father, and Child Cohort Study (MoBa) and the Medical Birth Registry of Norway (MBRN). Participants included mothers and fathers in the MoBa-study between 2004 and 2009. Agreement between dispensed ASM prescriptions and self-reported use was assessed by calculating Cohen's kappa (κ), sensitivity, and specificity, with self-reported use as the reference standard.

RESULTS

A total of 40 632 pregnant women and 42 247 fathers were included. Maternal dispensed ASM prescriptions during pregnancy showed strong overall agreement (κ = 0.81) with self-reported use, with a sensitivity of 80.6% and specificity of 99.9%. Paternal dispensed ASM prescriptions up to 7 months prior to conception also demonstrated strong agreement (κ = 0.81) with self-reported use. Analysis of individual ASMs revealed varying reliability: levetiracetam and lamotrigine had the highest agreement among maternal (κ = 0.92) and paternal (κ = 0.92) dispensed prescriptions, respectively.

CONCLUSION

There is strong agreement between dispensed ASM prescriptions and self-reported medication use by parents, supporting the use of prescription data for evaluating the risks of ASM use during pregnancy.

Use of signal detection methods to identify associations between prenatal medication exposure and subsequent childhood cancers: a Nordic hypothesis-generating registry-based study

BACKGROUND

Childhood cancer is an important contributor to childhood mortality in high-income countries. Information on associations between childhood cancer and in-utero exposure is absent or limited for most medications. Signal detection methods identify medications where research should be focused but have not been applied to datasets containing prenatal medication exposures and childhood cancers.

RESEARCH DESIGN AND METHODS

The aim of this study was to apply and evaluate four signal detection methods - odds ratios (OR), the information component (IC), sequential probability ratio testing (SPRT), and Bayesian hierarchical models (BHM) - for identification of associations between medications dispensed during pregnancy and subsequent, incident diagnosis of childhood cancer <10 years, using linked Nordic registry data. Signal detection results were compared to propensity score adjusted odds ratios from generalized linear models.

RESULTS

Analysis was performed for 117 medication-cancer pairs with 5 or more observations. The OR had the greatest sensitivity (0.75). The IC had a greater specificity (0.98) than the OR (0.95).

CONCLUSIONS

The IC may be the most appropriate method for identifying signals within this type of data. Reported signals should not be considered sufficient evidence of causal association and must be followed-up by tailored investigations that consider confounding by indication.

Antidepressants in pregnancy: applying causal epidemiological methods to understand service-use outcomes in women and long-term neurodevelopmental outcomes in exposed children

Background

Antidepressants are commonly prescribed during pregnancy, despite a lack of evidence from randomised trials on the benefits or risks. Some studies have reported associations of antidepressants during pregnancy with adverse offspring neurodevelopment, but whether or not such associations are causal is unclear.

Objectives

To study the associations of antidepressants for depression in pregnancy with outcomes using multiple methods to strengthen causal inference.

Design

This was an observational cohort design using multiple methods to strengthen causal inference, including multivariable regression, propensity score matching, instrumental variable analysis, negative control exposures, comparison across indications and exposure discordant pregnancies analysis.

Setting

This took place in UK general practice.

Participants

Participants were pregnant women with depression.

Interventions

The interventions were initiation of antidepressants in pregnancy compared with no initiation, and continuation of antidepressants in pregnancy compared with discontinuation.

Main outcome measures

The maternal outcome measures were the use of primary care and secondary mental health services during pregnancy, and during four 6-month follow-up periods up to 24 months after pregnancy, and antidepressant prescription status 24 months following pregnancy. The child outcome measures were diagnosis of autism, diagnosis of attention deficit hyperactivity disorder and intellectual disability.

Data sources

UK Clinical Practice Research Datalink.

Results

Data on 80,103 pregnancies were used to study maternal primary care outcomes and were linked to 34,274 children with at least 4-year follow-up for neurodevelopmental outcomes. Women who initiated or continued antidepressants during pregnancy were more likely to have contact with primary and secondary health-care services during and after pregnancy and more likely to be prescribed an antidepressant 2 years following the end of pregnancy than women who did not initiate or continue antidepressants during pregnancy (odds ratioinitiation 2.16, 95% confidence interval 1.95 to 2.39; odds ratiocontinuation 2.40, 95% confidence interval 2.27 to 2.53). There was little evidence for any substantial association with autism (odds ratiomultivariableregression 1.10, 95% confidence interval 0.90 to 1.35; odds ratiopropensityscore 1.06, 95% confidence interval 0.84 to 1.32), attention deficit hyperactivity disorder (odds ratiomultivariableregression 1.02, 95% confidence interval 0.80 to 1.29; odds ratiopropensityscore 0.97, 95% confidence interval 0.75 to 1.25) or intellectual disability (odds ratiomultivariableregression 0.81, 95% confidence interval 0.55 to 1.19; odds ratiopropensityscore 0.89, 95% confidence interval 0.61 to 1.31) in children of women who continued antidepressants compared with those who discontinued antidepressants. There was inconsistent evidence of an association between initiation of antidepressants in pregnancy and diagnosis of autism in offspring (odds ratiomultivariableregression 1.23, 95% confidence interval 0.85 to 1.78; odds ratiopropensityscore 1.64, 95% confidence interval 1.01 to 2.66) but not attention deficit hyperactivity disorder or intellectual disability; however, but results were imprecise owing to smaller numbers.

Limitations

Several causal-inference analyses lacked precision owing to limited numbers. In addition, adherence to the prescribed treatment was not measured.

Conclusions

Women prescribed antidepressants during pregnancy had greater service use during and after pregnancy than those not prescribed antidepressants. The evidence against any substantial association with autism, attention deficit hyperactivity disorder or intellectual disability in the children of women who continued compared with those who discontinued antidepressants in pregnancy is reassuring. Potential association of initiation of antidepressants during pregnancy with offspring autism needs further investigation.

Future work

Further research on larger samples could increase the robustness and precision of these findings. These methods applied could be a template for future pharmaco-epidemiological investigation of other pregnancy-related prescribing safety concerns.

Funding

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (15/80/19) and will be published in full in Health Technology Assessment; Vol. 27, No. 15. See the NIHR Journals Library website for further project information.

Risk of drug use during pregnancy: master protocol for living systematic reviews and meta-analyses performed in the metaPreg project

BACKGROUND

Knowledge about the risks of drugs during pregnancy is continuously evolving due to the frequent publication of a large number of epidemiological studies. Systematic reviews and meta-analyses therefore need to be regularly updated to reflect these advances. To improve dissemination of this updated information, we developed an initiative of real-time full-scale living meta-analyses relying on an open online dissemination platform ( www.metapreg.org ).

METHOD

All living meta-analyses performed in this project will be conducted in accordance with this master protocol after adaptation of the search strategy. A systematic literature search of PubMed and Embase will be performed. All analytical studies (e.g., cohort, case-control, randomized studies) reporting original empirical findings on the association between in utero exposure to drugs and adverse pregnancy outcomes will be included. Study screening and data extraction will be performed in a semi-automation way supervised by a biocurator. A risk of bias will be assessed using the ROBINS-I tools. All clinically relevant pregnancy adverse outcomes (malformations, stillbirths, neuro-developmental disorders, pre-eclampsia, etc.) available in the included studies will be pooled through random-effects meta-analysis. Heterogeneity will be evaluated by I² statistics.

DISCUSSION

Our living systematic reviews and subsequent updates will inform the medical, regulatory, and health policy communities as the news results evolve to guide decisions on the proper use of drugs during the pregnancy.

SYSTEMATIC REVIEW REGISTRATION

Open Science Framework (OSF) registries.

Effects of prenatal exposure to (es)citalopram and maternal depression during pregnancy on DNA methylation and child neurodevelopment

Studies assessing associations between prenatal exposure to antidepressants, maternal depression, and offspring DNA methylation (DNAm) have been inconsistent. Here, we investigated whether prenatal exposure to citalopram or escitalopram ((es)citalopram) and maternal depression is associated with differences in DNAm. Then, we examined if there is an interaction effect of (es)citalopram exposure and DNAm on offspring neurodevelopmental outcomes. Finally, we investigated whether DNAm at birth correlates with neurodevelopmental trajectories in childhood. We analyzed DNAm in cord blood from the Norwegian Mother, Father and Child Cohort Study (MoBa) biobank. MoBa contains questionnaire data on maternal (es)citalopram use and depression during pregnancy and information about child neurodevelopmental outcomes assessed by internationally recognized psychometric tests. In addition, we retrieved ADHD diagnoses from the Norwegian Patient Registry and information on pregnancies from the Medical Birth Registry of Norway. In total, 958 newborn cord blood samples were divided into three groups: (1) prenatal (es)citalopram exposed (n = 306), (2) prenatal maternal depression exposed (n = 308), and (3) propensity score-selected controls (n = 344). Among children exposed to (es)citalopram, there were more ADHD diagnoses and symptoms and delayed communication and psychomotor development. We did not identify differential DNAm associated with (es)citalopram or depression, nor any interaction effects on neurodevelopmental outcomes throughout childhood. Trajectory modeling identified subgroups of children following similar developmental patterns. Some of these subgroups were enriched for children exposed to maternal depression, and some subgroups were associated with differences in DNAm at birth. Interestingly, several of the differentially methylated genes are involved in neuronal processes and development. These results suggest DNAm as a potential predictive molecular marker of later abnormal neurodevelopmental outcomes, but we cannot conclude whether DNAm links prenatal (es)citalopram exposure or maternal depression with child neurodevelopmental outcomes.

Psychiatric visits during the postpartum year in women with eating disorders who continue or discontinue antidepressant treatment in pregnancy

OBJECTIVE

To determine the association between continued antidepressant use in pregnancy and postpartum psychiatric visits for eating (ED) or mood/anxiety disorders in women with preexisting ED.

METHOD

Using Danish health registry data (1998-2015), we identified 3529 pregnancies in women with ED prepregnancy: (i) 564 with continued antidepressant use before and during pregnancy; (ii) 778 with discontinued antidepressants before pregnancy; (iii) 2137 unexposed. Outpatient and inpatient postpartum visits for an ED or a mood/anxiety disorder constituted the outcome measures. We estimated hazard ratios (HRs) and 95% confidence intervals (CI) using Cox regression with inverse probability of treatment weighting, and performed stratified analyses by antidepressant prescription filling in the first 3 months postpartum.

RESULTS

The weighted cumulative incidence for an ED visit at end of follow-up was 4.5% (continued) and 4.8% (discontinued). We found no association between continued antidepressant and postpartum ED visit, relative to discontinued (HR: 0.89, 95% CI: 0.52-1.52). The HR for postpartum mood/anxiety disorder visit was 1.27 (95% CI: 0.68-2.36) with continued antidepressants versus discontinued but decreased if more than two antidepressant prescriptions were refilled. Continued antidepressant use was associated with a 57% reduced likelihood of a postpartum ED visit versus discontinued use in pregnancies with antidepressant prescription refills in the early postpartum.

CONCLUSION

Among women with preexisting ED, there was no association between continued antidepressant use during pregnancy and the likelihood of postpartum psychiatric visits, relative to discontinued antidepressants before pregnancy. Continuation of treatment into the early postpartum is associated with reduced likelihood of postpartum ED visit.

PUBLIC SIGNIFICANCE

Based on data from the Danish registries, we identified 3529 pregnancies among women with preexisting eating disorders before pregnancy. Women with continued antidepressant treatment both before and during pregnancy did not have a lower probability of having postpartum psychiatric visits for an eating disorder or for mood/anxiety disorders (often coexisting with eating disorders), relative to those who discontinued antidepressants before pregnancy. Further continuation of antidepressant treatment into the early postpartum is associated with improved maternal postpartum outcomes. However, residual confounding by disease severity limits confidence in this conclusion.

Visualizations throughout pharmacoepidemiology study planning, implementation, and reporting

Transparency is increasingly promoted to instill trust in nonrandomized studies using real-world data. Graphics and data visualizations support transparency by aiding communication and understanding, and can inform study design and analysis decisions. However, other than graphical representation of a study design and flow diagrams (e.g., a Consolidated Standards of Reporting Trials [CONSORT] like diagram), specific standards on how to maximize validity and transparency with visualization are needed. This paper provides guidance on how to use visualizations throughout the life cycle of a pharmacoepidemiology study-from initial study design to final report-to facilitate rationalized and transparent decision-making about study design and implementation, and clear communication of study findings. Our intent is to help researchers align their practices with current consensus statements on transparency.

Association between antidepressant use in pregnancy and gestational diabetes mellitus: Results from the Norwegian Mother, Father and Child Cohort Study

PURPOSE

This study sought to determine the association between gestational diabetes mellitus (GDM) and antidepressant exposure during early-mid pregnancy, overall and according to antidepressant affinity to the histamine-1 (H₁ ) receptor.

METHODS

Data originate from the nation-wide, Norwegian Mother, Father and Child Cohort Study conducted in 1999-2008, linked to the national Medical Birth Registry. The study included 6647 pregnancies within women with depressive/anxiety disorders during and/or 6 months prior to pregnancy. Pregnancies exposed in early-mid gestation to antidepressants having low (group 1, n = 814) or high (group 2, n = 77) affinity to the H₁ receptor were compared to non-medicated (n = 5756). We fit crude and weighted modified Poisson regression models using inverse probability of treatment weighting (IPTW).

RESULTS

Overall, 84 (1.3%) of the pregnancies developed GDM. Relative to non-medicated pregnancies, the risk of GDM was slightly lower in antidepressant group 1 exposed (1.3% vs 1.1%), but more elevated in those exposed to group 2 antidepressants (3.9%). In the weighted analysis, there was no evidence for an association between antidepressant group 1 exposure in early-mid pregnancy and risk of GDM [relative risk (RR): 0.69, 95% confidence interval: 0.31-1.51].

CONCLUSIONS

Gestational use of antidepressants with low H₁ receptor affinity, mainly SSRIs and SNRIs, does not pose a substantial risk of GDM in women with depressive/anxiety disorders in pregnancy, compared to no use.

Maternal Medication Use and Childhood Cancer in Offspring-Systematic Review and Considerations for Researchers

Cancer is an important cause of childhood mortality, yet the etiology is largely unknown. A combination of pre- and postnatal factors is thought to be implicated, including maternal medication use. We aimed to provide: 1) a systematic review of peer-reviewed publications on associations between maternal medication use and childhood cancer, with a focus on study design and methodology; and 2) suggestions for how to increase transparency, limit potential biases, and improve comparability in studies on maternal medication use and childhood cancer. We conducted a systematic search in the PubMed, Embase, Scopus, Cochrane, and Web of Science databases to June 8, 2020. Altogether, 112 studies were identified. The reviewed studies were heterogeneous in study design, exposure, and outcome classification. In 21 studies (19%), the outcome was any childhood cancer. Of the 91 papers that reported on specific types of cancer, 62% did not report the cancer classification system. The most frequently investigated medication groups were sex hormones (46 studies, excluding fertility medications), and antiinfectives (37 studies). Suggestions for strengthening future pharmacoepidemiologic studies on maternal medication use and childhood cancer relate to choice of cancer classification system, exposure windows, and methods for identification of, and control for, potential confounders.

Antithyroid drug use during pregnancy and the risk of birth defects in offspring: systematic review and meta-analysis of observational studies with methodological considerations

AIMS

Maternal antithyroid drug (ATD) use during pregnancy has been associated with an increased risk of birth defects in offspring. Uncertainty remains on the size of this risk and how it compares to untreated hyperthyroidism due to methodological limitations of previous studies.

METHODS

Systematic review of MEDLINE and EMBASE identifying observational studies examining ATD use during pregnancy and risk of birth defects by 28 August 2020. Data were extracted on study characteristics, effect estimates and comparator groups. Adjusted effect estimates were pooled using a random-effects generic inverse variance method and absolute risk calculated.

RESULTS

Seven cohort studies and 1 case-control study involving 6 212 322 pregnancies and 388 976 birth defects were identified reporting regression effect estimates. Compared to an unexposed population comparison, the association between ATD use during pregnancy and birth defects in offspring was: adjusted risk ratio (aRR) 1.16 95% confidence interval (CI) 1.08-1.25 for propylthiouracil (PTU); aRR 1.28 95%CI 1.06-1.54 for methimazole/carbimazole (MMI/CMZ); aRR 1.51, 95%CI 1.16-1.97 for both MMI/CMZ and PTU; and aRR 1.15 95%CI 1.02-1.29 for untreated hyperthyroidism. The excess risk of any and major birth defects per 1000, respectively, was: 10.2 and 1.3 for PTU; 17.8 and 2.3 for MMI/CMZ; 32.5 and 4.1 for both MMI/CMZ and PTU; and 9.6 and 1.2 for untreated hyperthyroidism.

CONCLUSIONS

When appropriately analysed the risk of birth defects associated with ATD use in pregnancy is attenuated. Although still elevated, the risk of birth defects is smallest with PTU compared to MMI/CMZ and may be similar to that of untreated hyperthyroidism.

Identifying Drugs Inducing Prematurity by Mining Claims Data with High-Dimensional Confounder Score Strategies

BACKGROUND

Pregnant women are largely exposed to medications. However, knowledge is lacking about their effects on pregnancy and the fetus.

OBJECTIVE

This study sought to evaluate the potential of high-dimensional propensity scores and high-dimensional disease risk scores for automated signal detection in pregnant women from medico-administrative databases in the context of drug-induced prematurity.

METHODS

We used healthcare claims and hospitalization discharges of a 1/97th representative sample of the French population. We tested the association between prematurity and drug exposure during the trimester before delivery, for all drugs prescribed to at least five pregnancies. We compared different strategies (1) for building the two scores, including two machine-learning methods and (2) to account for these scores in the final logistic regression models: adjustment, weighting, and matching. We also proposed a new signal detection criterion derived from these scores: the p value relative decrease. Evaluation was performed by assessing the relevance of the signals using a literature review and clinical expertise.

RESULTS

Screening 400 drugs from a cohort of 57,407 pregnancies, we observed that choosing between the two machine-learning methods had little impact on the generated signals. Score adjustment performed better than weighting and matching. Using the p value relative decrease efficiently filtered out spurious signals while maintaining a number of relevant signals similar to score adjustment. Most of the relevant signals belonged to the psychotropic class with benzodiazepines, antidepressants, and antipsychotics.

CONCLUSIONS

Mining complex healthcare databases with statistical methods from the high-dimensional inference field may improve signal detection in pregnant women.

Acetaminophen use during pregnancy and offspring attention deficit hyperactivity disorder - a longitudinal sibling control study

Background

Maternal acetaminophen use during pregnancy is associated with increased risk of ADHD in the child. This could reflect causal influence of acetaminophen on fetal neurodevelopment or could be due to confounding factors. The aim of the current study was to examine unmeasured familial confounding factors of this association.

Methods

We used data from 26,613 children from 12,902 families participating in the prospective Norwegian Mother, Father, and Child Cohort Study (MoBa). The MoBa was linked to the Norwegian Medical Birth Register and the Norwegian Patient Registry. Siblings discordant for prenatal acetaminophen exposure were compared regarding risk of having an ADHD diagnosis.

Results

Children exposed to acetaminophen up to 28 days during pregnancy did not have increased risk of receiving an ADHD diagnosis compared to unexposed children. The adjusted Hazard ratio (aHR) was 0.87 (95% C.I. = 0.70-1.08) for exposure 1 to 7 days, and 1.13 (95% C.I. = 0.82-1.49) for 8-28 days. Long-term exposure (29 days or more) was associated with a two-fold increase in risk of ADHD diagnosis (aHR = 2.02, 95% C.I = 1.17-3.25). In the sibling control model, the association between long-term acetaminophen use and ADHD in the child was aHR = 2.77 (95% C.I. = 1.48-5.05) at the between-family level, and aHR = 1.06 (95% C.I. = 0.51-2.05) at the within-family level.

Conclusions

Both the exposed and the unexposed children of mothers with long-term use of acetaminophen in one of the pregnancies had increased risk of receiving an ADHD diagnosis. This indicates that the observed association between long-term acetaminophen use during pregnancy and ADHD in the child may at least partly be confounded by unobserved family factors.

Attention-deficit/hyperactivity disorder in children following prenatal exposure to antidepressants: results from the Norwegian mother, father and child cohort study

OBJECTIVE

To determine the association between child attention-deficit/hyperactivity disorder (ADHD) and prenatal exposure to selective serotonin (SSRI) and serotonin-norepinephrine (SNRI) reuptake inhibitor antidepressants, by timing and duration, with quantification of bias due to exposure misclassification.

DESIGN

Norwegian Mother, Father and Child Cohort Study and national health registries.

SETTING

Nationwide, Norway.

POPULATION

A total of 6395 children born to women who reported depression/anxiety in pregnancy and were either medicated with SSRI/SNRI in pregnancy (n = 818) or non-medicated (n = 5228), or did not report depression/anxiety but used antidepressants 6 months before pregnancy (discontinuers, n = 349).

MAIN OUTCOME MEASURE

Diagnosis of ADHD or filled prescription for ADHD medication in children, and mother-reported symptoms of ADHD by child age 5 years.

RESULTS

When the hazard was averaged over the duration of the study follow up, there was no difference in ADHD risk between ever in utero SSRI/SNRI-exposed children and comparators (weighted hazard ratio [wHR] 1.07, 95% CI 0.76-1.51 versus non-medicated; wHR 1.53, 95% CI 0.77-3.07 versus discontinuers). Underestimation of effects due to exposure misclassification was modest. In early childhood, the risk for ADHD was lower with prenatal SSRI/SNRI exposure compared with no exposure, and so were ADHD symptoms (weighted β -0.23, 95% CI -0.39 to -0.08); this risk became elevated at child age 7-9 years (wHR 1.93, 95% CI 1.22-3.05). Maternal depression/anxiety before pregnancy was independently associated with child ADHD.

CONCLUSION

Prenatal SSRI/SNRI exposure is unlikely to considerably increase the risk of child ADHD beyond that posed by maternal depression/anxiety. The elevated risk at child age 7-9 years needs to be elucidated.

TWEETABLE ABSTRACT

Women with depression who use antidepressants in pregnancy do not have greater risk of having children with ADHD. Findings in school-age children needs follow up.

Prenatal medication exposure and epigenetic outcomes: a systematic literature review and recommendations for prenatal pharmacoepigenetic studies

When used during pregnancy, analgesics and psychotropics pass the placenta to enter the foetal circulation and may induce epigenetic modifications. Where such modifications occur and whether they disrupt normal foetal developme nt, are currently unanswered questions. This field of prenatal pharmacoepigenetics has received increasing attention, with several studies reporting associations between in utero medication exposure and offspring epigenetic outcomes. Nevertheless, no recent systematic review of the literature is available. Therefore, the objectives of this review were to (i) provide an overview of the literature on the association of prenatal exposure to psychotropics a nd analgesics with epigenetic outcomes, and (ii) suggest recommendations for future studies within prenatal pharmacoepigenetics. We performed systematic literature searches in five databases. The eligible studies assessed human prenatal exposure to psychotropics or analgesics, with epigenetic analyses of offspring tissue as an outcome. We identified 18 eligible studies including 4,419 neonates exposed to either antidepressants, antiepileptic drugs, paracetamol, acetylsalicylic acid, or methadone. The epigenetic outcome in all studies was DNA methylation in cord blood, placental tissue or buccal cells. Although most studies found significant differences in DNA methylation upon medication exposure, almost no differences were persistent across studies for similar medications and sequencing methods. The reviewed studies were challenging to compare due to poor transparency in reporting, and heterogeneous methodology, design, genome coverage, and statistical modelling. We propose 10 recommendations for future prenatal pharmacoepigenetic studies considering both epidemiological and epigenetic perspectives. These recommendations may improve the quality, comparability, and clinical relevance of such studies. PROSPERO registration ID: CRD42020166675.

Association between Antidepressant Treatment during Pregnancy and Postpartum Self-Harm Ideation in Women with Psychiatric Disorders: A Cross-Sectional, Multinational Study

This study sought to estimate whether there is a preventative association between antidepressants during pregnancy and postpartum self-harm ideation (SHI), as this knowledge is to date unknown. Using the Multinational Medication Use in Pregnancy Study, we included a sample of mothers who were in the five weeks to one year postpartum period at the time of questionnaire completion, and reported preexisting or new onset depression and/or anxiety during pregnancy (n = 187). Frequency of postpartum SHI ('often/sometimes' = frequent, 'hardly ever' = sporadic, 'never') was measured via the Edinburgh Postnatal Depression Scale (EPDS) item 10, which reads "The thought of harming myself has occurred to me". Mothers reported their antidepressant use in pregnancy retrospectively. Overall, 52.9% of women took an antidepressant during pregnancy. Frequent SHI postpartum was reported by 15.2% of non-medicated women and 22.0% of women on past antidepressant treatment in pregnancy; this proportion was higher following a single trimester treatment compared to three trimesters (36.3% versus 18.0%). There was no preventative association of antidepressant treatment in pregnancy on reporting frequent SHI postpartum (weighted RR: 1.90, 95% CI: 0.79, 4.56), relative to never/hardly ever SHI. In a population of women with antenatal depression/anxiety, there was no preventative association between past antidepressant treatment in pregnancy and reporting frequent SHI in the postpartum year. This analysis is only a first step in providing evidence to inform psychiatric disorder treatment decisions for pregnant women.

Polypharmacy and comorbidities during pregnancy in a cohort of women with migraine

OBJECTIVE

To describe longitudinal patterns of medication use throughout pregnancy in women with migraine.

METHODS

We used the IBM MarketScan healthcare claims database in the US to create a cohort of pregnancies enrolled between 2011-2015 resulting in live or stillbirth. Migraine headache was identified based on ICD-9-CM diagnosis codes or procedure codes recorded in clinical encounters. Outcomes were patterns of prescriptions filled for medications that may be used to prevent migraine (antiepileptics, antihypertensives, antidepressants) or treat acute episodes (opioids, triptans, acetaminophen) and of other comorbid conditions (hypertension, psychiatric diagnoses, epilepsy). We used group-based multi-trajectory models to cluster women into similar longitudinal patterns of prescription fills.

RESULTS

Of 859,501 pregnancies, 8168 had migraine. Within migraineurs, before pregnancy, the most commonly filled prescription was for a triptan (43.2%), followed by opioids (26.7%), acetaminophen (26.2%), antidepressants (24.9%), antiepileptics (18.6%) and antihypertensives (12.3%). Antiepileptics, antidepressants, and triptans were frequently discontinued early in pregnancy with few new users, while antihypertensives were discontinued by some users, but continued or initiated by a minority of users late in pregnancy. Opioids and acetaminophen were used intermittently throughout pregnancy. Comorbidities included hypertension (10.8%), epilepsy (4.7%), depression (14.0%), and anxiety (15.6%). Polypharmacy involving both preventive and acute medications was most common before pregnancy (31.4%) and declined in first trimester (14.7%). In all, 25.9% of women filled prescriptions for two or more acute medications before pregnancy.

CONCLUSIONS

Medication use patterns during pregnancy for women with migraine are complex. Patterns of polypharmacy and comorbidity during pregnancy highlight an under-studied area relevant for maternal and child health outcomes.

Perinatal epidemiology: Issues, challenges, and potential solutions

Perinatal epidemiology research is concerned with identifying the effects of events during pregnancy on pregnancy outcomes that include maternal, fetal, and neonatal health outcomes. Randomized trials in perinatal research face many challenges, including randomization difficulties, ethical considerations, and inadequate statistical power due to the small number of subjects eligible for participation. For these reasons, most epidemiological studies conducted in this research field are observational and include different types of bias. This review describes the key methodological difficulties in the design and analysis of randomized and observational studies in perinatal epidemiology, and provides potential corrective approaches.

Paternal antidepressant use as a negative control for maternal use: assessing familial confounding on gestational length and anxiety traits in offspring

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.

Prenatal paracetamol exposure and neurodevelopmental outcomes in preschool-aged children

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.

Advances in Epidemiological Methods and Utilisation of Large Databases: A Methodological Review of Observational Studies on Central Nervous System Drug Use in Pregnancy and Central Nervous System Outcomes in Children

INTRODUCTION

Studies have used various epidemiological approaches to study associations between central nervous system (CNS) drug use in pregnancy and CNS outcomes in children. Studies have generally focused on clinical adverse effects, whereas variations in methodologies have not received sufficient attention.

OBJECTIVE

Our objective was to review the methodological characteristics of existing studies to identify any limitations and recommend further research.

METHODS

A systematic literature search was conducted on observational studies listed in PubMed from 1 January 1946 to 21 September 2017. Following independent screening and data extraction, we conducted a review addressing the trends of relevant studies, differences between various data sources, and methods used to address bias and confounders; we also conducted statistical analyses.

RESULTS

In total, 111 observational studies, 25 case-control studies, and 86 cohort studies were included in the review. Publications dating from 1978 to 2006 mainly focused on antiepileptic drugs, but research on antidepressants increased from 2007 onwards. Only one study focused on antipsychotic use during pregnancy. A total of 46 studies obtained data from an administrative database/registry, 20 from ad hoc disease registries, and 41 from ad hoc clinical samples. Most studies (58%) adjusted the confounding factors using general adjustment, whereas only a few studies used advanced methods such as sibling-matched models and propensity score methods; 42 articles used univariate analyses and 69 conducted multivariable regression analyses.

CONCLUSION

Multiple factors, including different study designs and data sources, have led to inconsistent findings in associations between CNS drug use in pregnancy and CNS outcomes in children. Researchers should allow for study designs with clearly defined exposure periods, at the very least in trimesters, and use advanced confounding adjustment methodology to increase the accuracy of the findings.

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

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.

Annual Research Review: Maternal antidepressant use during pregnancy and offspring neurodevelopmental problems - a critical review and recommendations for future research

Children of women treated with antidepressants during pregnancy are more likely to develop neurodevelopmental problems than are unexposed children. Associations between prenatal antidepressant exposure and neurodevelopmental problems could reflect a causal effect or could be partially or fully explained by other factors that differ between exposed and unexposed offspring, including having mothers with conditions requiring antidepressant treatment (e.g. depression), environmental risk factors, and/or genetic risk factors shared across disorders. This translational review aims to provide a brief overview of findings from rodent experiments and critically evaluate observational studies in humans to assess the extent to which associations between prenatal antidepressant exposure and neurodevelopmental problems are due to causal mechanisms versus other influences. We focus our review on two important neurodevelopmental outcomes - autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD). In general, rodent studies have reported adverse effects of perinatal antidepressant exposure on neurodevelopment. Between-species differences raise questions about the generalizability of these findings to humans. Indeed, converging evidence from studies using multiple designs and approaches suggest that observed associations between prenatal antidepressant exposure and neurodevelopmental problems in humans are largely due to confounding factors. We also provide specific recommendations for future research. Animal research should explicitly evaluate the impact of timing of exposure and dosage of medications, as well as better map outcome measures in rodents to human neurodevelopmental problems. Observational studies should investigate specific confounding factors, specific antidepressant drugs and classes, the potential impact of timing of exposure, and a wider range of other potential offspring outcomes. The findings summarized in this review may help women and their doctors make informed decisions about antidepressant use during pregnancy by providing reassurance that use of these medications during pregnancy is unlikely to substantially increase the risk of ASD and ADHD.

Use of Negative Control Exposure Analysis to Evaluate Confounding: An Example of Acetaminophen Exposure and Attention-Deficit/Hyperactivity Disorder in Nurses' Health Study II

Frequent maternal use of acetaminophen in pregnancy has been linked to attention-deficit/hyperactivity disorder (ADHD) in children, but concerns regarding uncontrolled confounding remain. In this article, we illustrate use of the negative control exposure (NCE) approach to evaluate uncontrolled confounding bias in observational studies on pregnancy drug safety and explain the causal assumptions behind the method. We conducted an NCE analysis and evaluated the associations between maternal acetaminophen use during different exposure periods and ADHD among 8,856 children born in 1993-2005 to women enrolled in the Nurses' Health Study II cohort. Information on regular maternal acetaminophen use was collected prospectively in biennial questionnaires. A total of 721 children (8.1%) in the cohort had been diagnosed with ADHD as reported by the mothers. Our NCE analysis suggested that only acetaminophen use at the time of pregnancy was associated with childhood ADHD (odds ratio = 1.34, 95% confidence interval: 1.05, 1.72), and the effect estimates for the 2 NCE periods (about 4 years before and 4 years after the pregnancy) were null. Our findings corroborate those of prior reports suggesting that prenatal acetaminophen exposure may influence neurodevelopment. The lack of an association between acetaminophen use in the pre- and postpregnancy exposure periods and ADHD provides assurance that uncontrolled time-invariant factors do not explain this association.

Pharmacoepidemiology in pregnancy

Taking a medication is usually a challenge for a pregnant woman as the beneficial drug effect on the mother has to be considered regarding its potential adverse effects, not only for her but also for her unborn child. As medication use is common in pregnant women, by chance or necessity, it gives the opportunity to evaluate the consequences of prenatal drug exposure in real life through pharmacoepidemiological studies. This paper provides an overview of data sources, study designs and data analysis methods that can be used for pregnancy medication safety studies. In the future, the implementation of responsive international networks may be the keystones of drug evaluation in pregnancy.

Dr. Lupattelli et al. Reply

We thank Dr. Shaligram, author of this Letter to the Editor, for the interest in our recent article reporting time-dependent effects of prenatal exposure to selective serotonin reuptake inhibitors (SSRIs) on behavioral, emotional, and social development in offspring at age 5 years.¹ Dr. Shaligram raises interesting points of consideration for interpretation of the study results, and poses methodological questions about our window of exposure classification.².

Learning the effects of psychotropic drugs during pregnancy using real-world safety data: a paradigm shift toward modern pharmacovigilance

The growing evidence on psychotropic drug safety in pregnancy has been possible thanks to the increasing availability of real-world data, i.e. data not collected in conventional randomised controlled trials. Use of these data is a key to establish psychotropic drug effects on foetal, child, and maternal health. Despite the inherent limitations and pitfalls of observational data, these can still be informative after a critical appraisal of the collective body of evidence has been done. By valuing real-world safety data, and making these a larger part of the regulatory decision-making process, we move toward a modern pregnancy pharmacovigilance. The recent uptake of real-world safety data by health authorities has set the basis for an important paradigm shift, which is integrating such data into drug labelling. The recent safety assessment of sodium valproate in pregnant and childbearing women is probably one of the first examples of modern pregnancy pharmacovigilance.

Effect of Time-Dependent Selective Serotonin Reuptake Inhibitor Antidepressants During Pregnancy on Behavioral, Emotional, and Social Development in Preschool-Aged Children

OBJECTIVE

To evaluate the effect of prenatal exposure to selective serotonin reuptake inhibitors (SSRIs) on children's behavioral, emotional, and social development by age 5 years, and over time since age 1.5 years.

METHOD

The prospective Norwegian Mother and Child Cohort Study was linked to the Medical Birth Registry of Norway. We included women who reported depressive/anxiety disorders before and/or during pregnancy. Children born to women who used SSRIs in early (weeks 0-16), mid- (weeks 17-28), or late (> week 29) pregnancy were compared to those who were unexposed. Children's internalizing and externalizing behaviors (Child Behavior Checklist) and temperament traits (Emotionality, Activity and Shyness Temperament Questionnaire) were measured at 1.5, 3, and 5 years. Mean scores were calculated and standardized. General linear marginal structural models were fitted to account for time-varying exposure and confounders, and censoring; 3-level growth-curve models were used.

RESULTS

A total of 8,359 mother-child dyads were included, and 4,128 children had complete outcome data at age 5 years. Children exposed to SSRIs in late pregnancy had an increased risk of anxious/depressed behaviors by age 5 years compared with unexposed children (adjusted β = 0.50, 95% CI = 0.04, 0.96). Such risk was not evident for earlier timings of exposure. There was no evidence for a substantial prenatal SSRI effect on externalizing, social, and emotional problems.

CONCLUSION

These findings suggest no substantial increased risk for externalizing, emotional, or social problems in preschool-aged children following prenatal SSRI exposure. Although the role of chance and potential unmeasured confounding cannot be ruled out, late-pregnancy SSRI exposure was associated with greater anxious/depressed behaviors in the offspring.

Making fair comparisons in pregnancy medication safety studies: An overview of advanced methods for confounding control

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.