A Nation-Wide Swedish Cohort Study on Early Maternal Age at First Childbirth and Risk for Offspring Deaths, Accidents, and Suicide Attempts.

In a sample of over one million Swedish first-born offspring, we examined associations between early maternal age at first childbirth (MAFC; i.e., < 20 and 20-24 vs 25-29 years) and offspring non-accidental deaths, accidental deaths, deaths by suicide, non-fatal accidents, and suicide attempts. We included year of birth and several maternal and paternal characteristics as covariates and conducted maternal cousin comparisons to adjust for unmeasured confounding. Early MAFC (e.g., teenage childbearing) was associated with all outcomes, with the most pronounced risk elevation for accidental deaths [Hazard Ratio (HR) < 20 2.50, 95% confidence interval (CI) 2.23, 2.80], suicides (HR < 20 2.08, 95% CI 1.79, 2.41), and suicide attempts (HR < 20 2.85, 95% CI 2.71, 3.00). Adjusting for covariates and comparing cousins greatly attenuated associations (e.g., accidental deaths HR < 20 1.61, 95% CI 1.22, 2.11; suicides HR < 20 1.01, 95% CI 0.69, 1.47; and suicide attempts HR < 20 1.35, 95% CI 1.19, 1.52). A similar pattern emerged for non-accidental deaths and non-fatal accidents. Therefore, results indicated maternal background factors may be largely responsible for observed associations.

Accounting for Confounding in Observational Studies.

The goal of this review is to enable clinical psychology researchers to more rigorously test competing hypotheses when studying risk factors in observational studies. We argue that there is a critical need for researchers to leverage recent advances in epidemiology/biostatistics related to causal inference and to use innovative approaches to address a key limitation of observational research: the need to account for confounding. We first review theoretical issues related to the study of causation, how causal diagrams can facilitate the identification and testing of competing hypotheses, and the current limitations of observational research in the field. We then describe two broad approaches that help account for confounding: analytic approaches that account for measured traits and designs that account for unmeasured factors. We provide descriptions of several such approaches and highlight their strengths and limitations, particularly as they relate to the etiology and treatment of behavioral health problems.

Maternal prescribed opioid analgesic use during pregnancy and associations with adverse birth outcomes: A population-based study.

BACKGROUND: Published research on prescribed opioid analgesic (POA) use during pregnancy and birth outcomes is limited in scope and has not adequately adjusted for potential confounding factors. To help address these gaps, we estimated associations between maternal POAs during pregnancy and two adverse birth outcomes using a large population-based dataset, multiple definitions of POA exposure, and several methods to evaluate the influence of both measured and unmeasured confounding factors. METHODS AND FINDINGS: We obtained data by linking information from several Swedish registers and conducted a retrospective cohort study on a population-based sample of 620,458 Swedish births occurring between 2007 and 2013 (48.6% female; 44.4% firstborn). We evaluated associations between prenatal POA exposure and risk for preterm birth (PTB; <37 gestational weeks) and small for gestational age (SGA; birth weight 2 standard deviations below the expected weight for gestational age or lower). We evaluated the influence of confounding by adjusting for a wide range of measured covariates while comparing exposed and unexposed infants. Additionally, we adjusted for unmeasured confounding factors by using several advanced epidemiological designs. Infants exposed to POAs anytime during pregnancy were at increased risk for PTB compared with unexposed infants (6.4% exposed versus 4.4% unexposed; adjusted odds ratio [OR] = 1.38, 95% confidence interval [CI] 1.31-1.45, p < 0.001). This association was attenuated when we compared POA-exposed infants with acetaminophen-exposed infants (OR = 1.18, 95% CI 1.07-1.30, p < 0.001), infants born to women who used POAs before pregnancy only (OR = 1.05, 95% CI 0.96-1.14, p = 0.27), and unexposed siblings (OR = 0.99, 95% CI 0.85-1.14, p = 0.92). We also evaluated associations with short-term versus persistent POA use during pregnancy and observed a similar pattern of results, although the magnitudes of associations with persistent exposure were larger than associations with any use or short-term use. Although short-term use was not associated with SGA (adjusted ORsingle-trimester = 0.95, 95% CI 0.87-1.04, p = 0.29), persistent use was associated with increased risk for SGA (adjusted ORmultiple-trimester = 1.40, 95% CI 1.17-1.67, p < 0.001) compared with unexposed infants. The association with persistent exposure was attenuated when we used alternative comparison groups (e.g., sibling comparison OR = 1.22, 95% CI 0.60-2.48, p = 0.58). Of note, our study had limitations, including potential bias from exposure misclassification, an inability to adjust for all sources of confounding, and uncertainty regarding generalizability to countries outside of Sweden. CONCLUSIONS: Our results suggested that observed associations between POA use during pregnancy and risk of PTB and SGA were largely due to unmeasured confounding factors, although we could not rule out small independent associations, particularly for persistent POA use during pregnancy.

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.

Associations of Maternal Antidepressant Use During the First Trimester of Pregnancy With Preterm Birth, Small for Gestational Age, Autism Spectrum Disorder, and Attention-Deficit/Hyperactivity Disorder in Offspring.

Importance: Prenatal antidepressant exposure has been associated with adverse outcomes. Previous studies, however, may not have adequately accounted for confounding. Objective: To evaluate alternative hypotheses for associations between first-trimester antidepressant exposure and birth and neurodevelopmental problems. Design, Setting, and Participants: This retrospective cohort study included Swedish offspring born between 1996 and 2012 and followed up through 2013 or censored by death or emigration. Analyses controlling for pregnancy, maternal and paternal covariates, as well as sibling comparisons, timing of exposure comparisons, and paternal comparisons, were used to examine the associations. Exposures: Maternal self-reported first-trimester antidepressant use and first-trimester antidepressant dispensations. Main Outcomes and Measures: Preterm birth (<37 gestational weeks), small for gestational age (birth weight <2 SDs below the mean for gestational age), and first inpatient or outpatient clinical diagnosis of autism spectrum disorder and attention-deficit/hyperactivity disorder in offspring. Results: Among 1 580 629 offspring (mean gestational age, 279 days; 48.6% female; 1.4% [n = 22 544] with maternal first-trimester self-reported antidepressant use) born to 943 776 mothers (mean age at childbirth, 30 years), 6.98% of exposed vs 4.78% of unexposed offspring were preterm, 2.54% of exposed vs 2.19% of unexposed were small for gestational age, 5.28% of exposed vs 2.14% of unexposed were diagnosed with autism spectrum disorder by age 15 years, and 12.63% of exposed vs 5.46% of unexposed were diagnosed with attention-deficit/hyperactivity disorder by age 15 years. At the population level, first-trimester exposure was associated with all outcomes compared with unexposed offspring (preterm birth odds ratio [OR], 1.47 [95% CI, 1.40-1.55]; small for gestational age OR, 1.15 [95% CI, 1.06-1.25]; autism spectrum disorder hazard ratio [HR], 2.02 [95% CI, 1.80-2.26]; attention-deficit/hyperactivity disorder HR, 2.21 [95% CI, 2.04-2.39]). However, in models that compared siblings while adjusting for pregnancy, maternal, and paternal traits, first-trimester antidepressant exposure was associated with preterm birth (OR, 1.34 [95% CI, 1.18-1.52]) but not with small for gestational age (OR, 1.01 [95% CI, 0.81-1.25]), autism spectrum disorder (HR, 0.83 [95% CI, 0.62-1.13]), or attention-deficit/hyperactivity disorder (HR, 0.99 [95% CI, 0.79-1.25]). Results from analyses assessing associations with maternal dispensations before pregnancy and with paternal first-trimester dispensations were consistent with findings from the sibling comparisons. Conclusions and Relevance: Among offspring born in Sweden, after accounting for confounding factors, first-trimester exposure to antidepressants, compared with no exposure, was associated with a small increased risk of preterm birth but no increased risk of small for gestational age, autism spectrum disorder, or attention-deficit/hyperactivity disorder.

Translational Epidemiologic Approaches to Understanding the Consequences of Early-Life Exposures.

Prominent developmental theories posit a causal link between early-life exposures and later functioning. Yet, observed associations with early exposures may not reflect causal effects because of genetic and environmental confounding. The current manuscript describes how a systematic series of epidemiologic analyses that combine several genetically-informative designs and statistical approaches can help distinguish between competing theories. In particular, the manuscript details how combining the use of measured covariates with sibling-comparisons, cousin-comparisons, and additional designs can help elucidate the sources of covariation between early-life exposures and later outcomes, including the roles of (a) factors that are not shared in families, including a potential causal effect of the exposure; (b) carryover effects from the exposure of one child to the next; and (c) familial confounding. We also describe key assumptions and how they can be critically evaluated. Furthermore, we outline how subsequent analyses, including effect decomposition with respect to measured, plausible mediators, and quantitative genetic models can help further specify the underlying processes that account for the associations between early-life exposures and offspring outcomes.

A Genetically Informed Study of the Associations Between Maternal Age at Childbearing and Adverse Perinatal Outcomes.

We examined associations of maternal age at childbearing (MAC) with gestational age and fetal growth (i.e., birth weight adjusting for gestational age), using two genetically informed designs (cousin and sibling comparisons) and data from two cohorts, a population-based Swedish sample and a nationally representative United States sample. We also conducted sensitivity analyses to test limitations of the designs. The findings were consistent across samples and suggested that, associations observed in the population between younger MAC and shorter gestational age were confounded by shared familial factors; however, associations of advanced MAC with shorter gestational age remained robust after accounting for shared familial factors. In contrast to the gestational age findings, neither early nor advanced MAC was associated with lower fetal growth after accounting for shared familial factors. Given certain assumptions, these findings provide support for a causal association between advanced MAC and shorter gestational age. The results also suggest that there are not causal associations between early MAC and shorter gestational age, between early MAC and lower fetal growth, and between advanced MAC and lower fetal growth.

A nationwide study of initiation of antidepressant pharmacotherapy and the risk of seizures.

OBJECTIVE: The present study aimed to examine whether antidepressant initiation increases the risk of hospitalizations and unplanned outpatient visits for seizures. Research has provided conflicting evidence as to whether antidepressant initiation causes seizures. Because epilepsy and depression are comorbid, this remains an important question, particularly in the care of those already at-risk for seizures. METHODS: We used Swedish-register data, including 658,766 antidepressant initiators and 1:1 age-, region-, and sex-matched non-initiators, ages 12-65. We used filled prescriptions to identify any antidepressant and serotonergic antidepressant and inpatient hospitalizations and unplanned outpatient (to avoid coding routine epilepsy maintenance as a seizure) visits to identify seizures, respectively. We first compared seizure visit incidence between antidepressant-initiators and matched non-users in the year following initiation from 2006 to 2013. To examine seizure risk over months pre- and post-initiation, within-individual analyses compared risk during the month one year prior to initiation with all subsequent months. We examined associations for any antidepressant and serotonergic antidepressants, as well as for any initiator and initiators with a history of seizures. RESULTS: Our matched-cohort results showed higher incidence of seizure visits among antidepressant users compared with non-users (e.g., adjusted incidence rate ratio [IRR]=3.14, 95% confidence interval [CI]=2.83-3.49). In within-individual analyses, the months after initiation were associated with higher incidence of seizure visits when compared with the month one year prior to initiation (e.g., one month after initiation IRR=1.96, 95%CI=1.64-2.34), but in individuals with a seizure history we observed weaker or no associations in the months after initiation (e.g., two months after initiation IRR=1.12, 95%CI=0.87-1.45). Notably, irrespective of potential seizure history, the months preceding initiation were associated with the greatest risk (e.g., one month before initiation IRR=2.86, 95% CI=2.42-3.38). CONCLUSIONS: Our findings suggest that there may be an elevated risk of seizures during antidepressant treatment, though the period of highest risk was before the initiation of antidepressants. Risk for seizure visits was lower among individuals with a history of prior seizures, which may be reassuring for the clinical care of these patients or indicate lack of treatment seeking following seizures. This study highlights the need to consider seizure risk across time; the failure to account for these dynamics may help account for discrepant findings in previous studies.

A nation-wide Swedish study of opioid analgesic prescribing patterns during pregnancy and associated preexisting mental health conditions.

INTRODUCTION: Research has consistently shown individuals with mental health conditions are more likely to be prescribed opioid analgesic medications and to engage in heavier utilization. However, it is unclear whether these findings apply to pregnant women. STUDY DESIGN: We explored opioid analgesic prescription in 689,400 pregnancies occurring in Sweden between 2007 and 2013. We investigated prescription patterns across time and type of source clinic for any opioid analgesic and for strong and weak opioid analgesics. We further evaluated the extent to which receipt of opioid analgesic medications was associated with previous mental health diagnoses and prescriptions of other psychoactive medications. RESULTS: The prevalence of pregnant women who filled prescriptions for opioid analgesics (4.5%) was relatively stable across the assessed years. However, among pregnant women who filled opioid analgesic prescriptions, there was a large increase in strong opioid analgesic prescriptions-from 6.1% in 2007 to 17.1% in 2013. The main source of opioid analgesic prescriptions were primary care and obstetrics and gynecology clinics-38.7% of all filled prescriptions originated from primary care providers and 25.3% from obstetrics and gynecology practitioners. Compared to pregnant women who did not fill any opioid analgesic prescriptions, those who did were more likely to have a wide range of preexisting mental health diagnoses (e.g. anxiety disorder odds ratio [OR] = 3.13, 95% confidence interval [CI]:2.98,3.29) and to utilize a wide range of other psychoactive medications (e.g. benzodiazepines OR = 4.26, 95% CI:4.10,4.43). Similarly, those who received strong opioids were more likely to have a wide range of mental health diagnoses and be prescribed a wide range of psychoactive medications compared to those who received weak opioids. CONCLUSIONS: These results highlight the need for physicians treating pregnant women and women of childbearing age for painful conditions to obtain detailed histories of mental health problems, screen for symptoms of mental health problems, and facilitate integrated care and evidence-based mental health interventions if needed.

Maternal Serotonergic Antidepressant Use in Pregnancy and Risk of Seizures in Children.

OBJECTIVE: To evaluate whether children born to women who use serotonergic antidepressants during pregnancy have higher risk of neonatal seizures and epilepsy. METHODS: We used Swedish register-based data to examine associations between maternal-reported use of selective-serotonin reuptake inhibitor (SSRI) and selective serotonin-norepinephrine reuptake inhibitors (SNRI) in pregnancy and diagnosis of neonatal seizures and/or epilepsy in over 1.2 million children. To account for systematic differences between exposed and unexposed children we adjusted for a wide range of measured confounders. After first evaluating the role of maternal indication for SSRI/SNRI use (i.e., depression and anxiety) and parental epilepsy, we adjusted for remaining parental background factors (e.g., age, co-morbidities, education, and family socioeconomic indices) and pregnancy-specific characteristics (e.g., maternal use of other psychotropic medications and tobacco smoking in early pregnancy). RESULTS: Compared with all other children, children of women that reported use of SSRI/SNRI in pregnancy had an elevated risk of neonatal seizures and epilepsy (risk ratio [RR]=1.41, 95% confidence interval [CI]=1.03-1.94; hazard ratio [HR]=1.21, 95% CI=1.03-1.43 respectively). The estimates of association were attenuated by adjustment for maternal indications for SSRI/SNRI use (RR=1.30, 95% CI=0.94-1.79; HR = 1.13, 95% CI = 0.95-1.33), but not by additional adjustment for parental history of epilepsy. Full adjustment for all measured parental and pregnancy-specific factors resulted in substantial attenuation of the remaining associations (RR = 1.10, 95% CI = 0.79-1.53; HR = 0.96, 95% CI = 0.81-1.14). CONCLUSIONS: The present study found no support for the concern that maternal SSRI/SNRI use in pregnancy increases children's risk for neonatal seizures or epilepsy. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that exposure to SSRI/SNRI's in the first trimester of pregnancy is not associated with an increased incidence of neo-natal seizures/epilepsy.

Assisted Reproductive Techniques, ADHD, and School Performance.

OBJECTIVES: To examine the long-term impact of assisted reproductive techniques (ART) on offspring neurodevelopment, accounting for parental factors and the role of infertility. METHODS: Linkage of national registers allowed follow-up of >2.4 million children born in Sweden 1986-2012. Information on ART was retrieved from fertility clinics, medical records, and maternal self-report. Attention-deficit/hyperactivity disorder (ADHD) was identified from specialist diagnosis and/or use of medication through 2018. School performance was assessed from records of ninth year final grade averages (0-20) and eligibility for upper secondary school through 2017. RESULTS: Children conceived with ART had lower risk of ADHD (hazard ratio 0.83; 95% confidence interval [CI]: 0.80 to 0.87) and did better in school (grade mean difference 1.15; 95% CI: 1.09 to 1.21 and eligibility odds ratio 1.53; 95% CI: 1.45 to 1.63) compared with all other children. Differences in parental characteristics explained and even reversed associations, whereas no disadvantage was seen when the comparison was restricted to children of couples with known infertility (adjusted hazard ratio 0.95; 95% CI: 0.90 to 1.00, adjusted mean difference 0.05; 95% CI: -0.01 to 0.11, and adjusted odds ratio 1.03; 95% CI: 0.96 to 1.10). Among children conceived with ART, there was furthermore no indication that intracytoplasmic sperm injection (compared with standard in vitro fertilization) or frozen (compared with fresh) embryo transfer had any adverse influence. CONCLUSIONS: With this nationwide, long-term follow-up, we provide additional reassurance concerning offspring neurodevelopment after use of ART, finding no indication for concern about risk of ADHD or school performance in adolescence.

Associations of Prescribed ADHD Medication in Pregnancy with Pregnancy-Related and Offspring Outcomes: A Systematic Review.

BACKGROUND: Increasing numbers of reproductive-aged women are using attention-deficit/hyperactivity disorder (ADHD) medications. Findings from studies exploring the safety of these medications during pregnancy are mixed, and it is unclear whether associations reflect causal effects or could be partially or fully explained by other factors that differ between exposed and unexposed offspring. OBJECTIVES: The aim of this systematic review was to evaluate the adverse pregnancy-related and offspring outcomes associated with exposure to prescribed ADHD medication during pregnancy with a focus on how studies to date have handled the influence of confounding. METHODS: We searched PubMed, Embase, PsycINFO, and Web of Science up to 1 July 2019 without any restrictions on language or date of publication. We included all observational studies (e.g., cohort studies, case-control studies, case-crossover studies, cross-sectional studies, and registry-based studies) with pregnant women of any age or from any setting who were prescribed ADHD medications and evaluated any outcome, including both short- and long-term maternal and offspring outcomes. Two independent authors then used the Newcastle-Ottawa Scale to rate the quality of the included studies. RESULTS: Eight cohort studies that estimated adverse pregnancy-related and offspring outcomes associated with exposure to ADHD medication during pregnancy were included in the qualitative review. The included studies had substantial methodological differences in data sources, type of medications examined, definitions of studied pregnancy-related and offspring outcomes, types of control groups, and confounding adjustment. There was no convincing evidence for teratogenic effects according to the relative risk of pregnancy-related and offspring outcomes, and the observed differences in absolute risks were overall small in magnitude. Adjustment for confounding was inadequate in most studies, and none of the included studies adjusted for ADHD severity in the mothers. CONCLUSION: The current evidence does not suggest that the use of ADHD medication during pregnancy results in significant adverse consequences for mother or offspring. However, the data are too limited to make an unequivocal recommendation. Therefore, physicians should consider whether the advantages of using ADHD medication outweigh the potential risks for the developing fetus according to each woman's specific circumstances. Future research should attempt to triangulate research findings based on a combination of different designs that differ in their underlying strengths and limitations and should investigate specific confounding factors, the potential impact of timing of exposure, and potential long-term outcomes in the offspring.

Antiseizure medication use during pregnancy and risk of ASD and ADHD in children.

OBJECTIVE: To determine whether children born to women who use antiseizure medications (ASMs) during pregnancy have higher risk of autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) independent of confounding factors. METHODS: We used Swedish register data (n = 14,614 children born 1996-2011 and followed up through 2013) to examine associations in children of women with epilepsy, using the largest sample to date and adjusting for a range of measured confounders. We examined maternal-reported first-trimester use of any ASM (22.7%) and the 3 most commonly reported individual drugs (valproic acid 4.8%, lamotrigine 6.8%, and carbamazepine 9.7%). We identified ASD with ICD-10 diagnoses and ADHD with ICD-10 diagnoses or filled prescriptions of ADHD medication. RESULTS: Examination of individual drugs revealed that after adjustment for confounding, use of valproic acid was associated with ASD (hazard ratio [HR] 2.30, 95% confidence interval [CI] 1.53-3.47) and ADHD (HR 1.74, 95% CI 1.28-2.38). Whereas a small, nonstatistically significant association with ASD (HR 1.25, 95% CI = 0.88-1.79) and ADHD (HR 1.18, 95% CI 0.91-1.52) remained for reported use of carbamazepine, confounding explained all of the associations with lamotrigine (HRASD 0.86, 95% CI 0.67-1.53; HRADHD 1.01, 95% CI 0.67-1.53). CONCLUSIONS: We found no evidence of risk related to exposure to lamotrigine, whereas we observed elevated risk of ASD and ADHD related to maternal use of valproic acid. Associations with carbamazepine were weak and not statistically significant. Our findings add to a growing body of evidence that suggests that certain ASMs may be safer than others in pregnancy.