Maternal use of thyroid hormone replacement therapy before, during, and after pregnancy: agreement between self-report and prescription records and group-based trajectory modeling of prescription patterns

Levothyroxine Treatment Among Pregnant Women and Risk of Seizure in Children: A Population-Based Cohort Study

INTRODUCTION AND OBJECTIVE

The risk of seizure in offspring following prenatal exposure to levothyroxine is not well investigated. This study aimed to evaluate the association between levothyroxine treatment among pregnant women and the risk of seizure in their offspring.

METHODS

This population-based cohort study included all pregnant women who delivered a live birth between January 2001 to January 2018, with a follow-up to December 2020, using data from the Hong Kong Clinical Data Analysis and Reporting System. Propensity score fine-stratification weighted hazard ratios (wHR) with 95% confidence intervals (CIs) were presented to assess the association between maternal levothyroxine use during pregnancy and seizures in children.

RESULTS

Among 528,343 included mother-child pairs, 3044 children were prenatally exposed to levothyroxine at any time during the pregnancy period. A significantly increased risk of seizure was observed in children of the prenatally exposed group compared with the prenatally unexposed group (wHR 1.12, 95% CI 1.02-1.22). An increased risk of seizure was observed when comparing the prenatally exposed group with euthyroid mothers who had no history of thyroid-related diagnosis or prescriptions (wHR 1.12, 95% CI 1.02-1.23). However, no significant difference was observed between the prenatally exposed group and those previously exposed to levothyroxine but had stopped during pregnancy (wHR 0.97, 95% CI 0.66-1.44). No significant difference was observed in the sibling-matched analysis either (wHR 1.23, 95% CI 0.76-2.01).

CONCLUSION

The observed increased risk of seizure in children born from mothers exposed to levothyroxine during pregnancy might be due to residual confounding by maternal thyroid disease. The findings support the current guidelines on the safe use of levothyroxine treatment during pregnancy.

Trajectories of ADHD medication use before, during, and after pregnancy: A population-based study from Norway and Sweden

PURPOSE

To describe ADHD medication use trajectories around pregnancy in Norway and Sweden.

METHODS

We identified pregnancies resulting in births using linked data from birth and prescribed drug registers of Norway (2006-2019, N = 813 107) and Sweden (2007-2018, N = 1 269 146). We restricted to women who filled prescriptions for ADHD medication during pregnancy or in the year before or after. We described exposure as use versus no use, and total amount of drug dispensed in defined daily doses (DDDs). Group-based trajectory modeling was used to identify distinct medication use trajectories.

RESULTS

In total, 13 286 women (0.64%) filled a prescription for ADHD medication. We identified four trajectory groups: continuers (5.7%), interrupters (23.8%), discontinuers (49.5%), and late initiators (21.0%). Discontinuers were younger, continuers were older on average. More women continued medication in recent years (2014-2019). Most discontinuers (60.7%) were nulliparous; more initiators and continuers had one or multiple previous births, respectively. Continuers were least likely to live with a partner (65.8%). Discontinuers were least likely (24.7%) and continuers most likely (37.6%) to smoke at the beginning of pregnancy. More continuers used amphetamine derivatives and were most likely to use other psychotropics. On modeling continuers, we identified three dose-trajectory groups which suggested that most women reduced medication dose during pregnancy.

CONCLUSIONS

Most pregnant women discontinued or interrupted their ADHD medication during pregnancy, but more continued in recent years. Continuers were more likely to have had previous births, less likely to have lived with a partner, and may have had additional comorbidities warranting the use of other psychotropics.

Antidepressant Fill and Dose Trajectories in Pregnant Women with Depression and/or Anxiety: A Norwegian Registry Linkage Study

Background

Few studies investigated longitudinal antidepressant exposure during pregnancy and included dosage in the assessment.

Methods

We conducted a nationwide, registry-linkage study in Norway using data on antidepressant prescription fills in pregnancies lasting ≥32 weeks in women with a delivery between 2009 and 2018 who had a depression/anxiety diagnosis and antidepressant fills prior to pregnancy. Information on antidepressant exposure by week (measured by filled prescriptions) and prescribed average daily dose was used in longitudinal k-means trajectory modelling for a 108-week time window from six months prior to pregnancy to one year after delivery. Factors associated with trajectory group membership were examined using multinomial logistic regression models.

Results

We included 8,460 pregnancies in 8,092 women. Four antidepressant fill trajectories were identified based on filled antidepressant prescriptions: two distinct discontinuing patterns, one at around the start of pregnancy (30.4%) and one around the end of pregnancy (33.8%); one continuing pattern (20.6%); and one interrupting pattern (15.2%). Using average usual daily dose, we identified low dose discontinuing (60.3%), medium dose reducing (20.6%) and high dose continuing (15.2%) patterns. The multinomial logistic regressions showed that the fill trajectory group membership was strongly associated with: antidepressant type and dose prior to pregnancy and co-medication prior to pregnancy, maternal age, marital status, parity, previous pregnancy loss, and pregnancy planning.

Conclusion

Longitudinal trajectory modelling revealed distinct antidepressant fill and dosage patterns in the period around pregnancy. Knowledge about factors associated with utilization trajectories might be useful for health-care personnel counselling women about antidepressant use in pregnancy.

Under and overtreatment with thyroid hormone replacement during pregnancy

PURPOSE OF REVIEW

Among pregnant women on thyroid hormone replacement therapy undertreatment is common, while overtreatment is rare. Both deficient and excessive maternal thyroid hormone have been related to adverse maternofetal and long-term offspring outcomes, although studies' results are inconsistent. This review aims to discuss recent evidence regarding the effects of under- and overtreatment with thyroid hormone replacement during pregnancy and how current practices could be improved.

RECENT FINDINGS

Whether or not thyroid hormone therapy needs to be initiated for maternal subclinical hypothyroidism remains unclear, but recent meta-analyses have confirmed associations between adverse maternal, neonatal, and offspring outcomes in both overt and subclinical hypothyroidism. Subclinical hyperthyroidism in pregnancy is related to fewer adverse outcomes. Current adherence to levothyroxine during pregnancy and medication counseling by healthcare providers are suboptimal.

SUMMARY

Undertreatment of maternal hypothyroidism may increase risks for adverse maternofetal and offspring effects more than overtreatment does. If thyroid hormone replacement therapy is indicated and initiated in pregnancy, frequent thyroid function monitoring is required to avoid under- or overtreatment. Effective communication between clinicians and patients is imperative to increase medication adherence.

What methods are used to study the association between medication adherence trajectories, estimated with the group-based trajectory modeling (GBTM) method, and health-related outcomes?-a protocol for a systematic review

BACKGROUND

The group-based trajectory modeling (GBTM) method is increasingly used in pharmacoepidemiologic studies to describe medication adherence trajectories over time. However, assessing the associations between these medication adherence trajectories and health-related outcomes remains challenging. The purpose of this review is to identify and systematically review the methods used to assess the association between medication adherence trajectories, estimated from the GBTM method, and health-related outcomes.

METHODS

We will conduct a systematic review according to the recommendations of the Cochrane handbook for systematic reviews of interventions 6.2. Results will be reported following PRISMA 2020 (Preferred Reporting Items for Systematic Reviews and Meta-analyses) recommendations. We will search in the following databases: PubMed, Embase, PsycINFO, Web of Science, CINAHL, and Cochrane Library. Two reviewers will independently select articles and extract data. Discrepancies at every step will be resolved through discussion, and consensus will be reached for all disagreed articles. A third reviewer will act as a referee if needed. We will produce tables to synthesize the modalities used to estimate medication adherence trajectories with GBTM. We will also synthesize the modalities used to assess the association between these medication adherence trajectories and health-related outcomes by identifying the types of health-related outcomes studied and how they are defined, the statistical models used, and how the medication adherence trajectories were used in these models, and the effect measure yield. We will also review the limitations and biases reported by the authors and their attempts to mitigate them. We will provide a narrative synthesis.

DISCUSSION

This review will provide a thorough exploration of the strategies and methods used in medication adherence research to estimate the associations between medication adherence trajectories, estimated with GBTM, and the different health-related outcomes. It will represent the first crucial steps toward optimizing these methods in adherence studies.

SYSTEMATIC REVIEW REGISTRATION

Prospero CRD42021213503 .

Longitudinal Methods for Modeling Exposures in Pharmacoepidemiologic Studies in Pregnancy

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.

Exploring Links Between Prenatal Adversity and Adolescent Psychiatric Risk in a Canadian Population-Based Sample

OBJECTIVE

Adverse prenatal and postnatal exposures may have long-lasting effects on health and development. However, it remains unclear whether being exposed to a greater number of prenatal adversities affects mental health risk. The current study examined whether exposure to maternal health problems prenatally is associated with an increasing risk of psychiatric morbidity in adolescents.

METHODS

Using data from the 2014 Ontario Child Health Study (OCHS), we examined associations between a count of 7 prenatal risk factors (maternal hypertension, diabetes mellitus, bleeding during pregnancy, influenza, urinary tract infection, thyroid disease, and depression/anxiety) and adolescent psychiatric morbidity. Adolescents (N = 2219) aged 12 to 17 years were assessed using the Mini-International Neuropsychiatric Interview for Children and Adolescents.

RESULTS

Exposure to each additional prenatal adversity was correlated with increased odds of attention-deficit/hyperactivity disorder (odds ratio [OR] = 1.29, 95% confidence interval [CI] = 1.03-1.60), generalized anxiety disorder (OR = 1.27, 95% CI = 1.05-1.55), and social anxiety disorder (OR = 1.35, 95% CI = 1.01-1.80) after adjustment for confounding variables.

CONCLUSION

Exposure to prenatal adversity in the form of maternal health problems was correlated with an increased risk of attention deficit hyperactivity disorder and anxiety disorders in adolescence. Future studies should further investigate the effects of antenatal environmental exposures on these associations to determine the potential value of close monitoring of those exposed to prenatal risks.

Thyroid hormone replacement therapy in pregnancy and motor function, communication skills, and behavior of preschool children: The Norwegian Mother, Father, and Child Cohort Study

PURPOSE

Limited research has focused on the association between prenatal thyroid hormone replacement therapy (THRT) and motor function, communication skills, and behavior in preschool children. Here, we estimated the association between THRT during pregnancy and the first trimester and these developmental outcomes.

METHODS

This study was based on the Norwegian Mother, Father, and Child Cohort Study (MoBa) and other national registries. We included mother-child pairs exposed to THRT during pregnancy (n = 663), after delivery (n = 728), or unexposed (n = 28 040). Exposure to THRT was defined according to filled prescriptions. Child outcomes, presented as T-score differences, were parent-reported using the Ages and Stages Questionnaire, Strengths and Difficulties Questionnaire, and Child Behavior Checklist.

RESULTS

Of 29 431 mother-child pairs, 2.3% were prenatally exposed to THRT. We found no difference between prenatally exposed and unexposed children in regards to gross motor function (β: 0.17, 95% CI -1.19, 1.54), fine motor function (β: -0.17, 95% CI -1.14, 0.80), communication (β: -0.31, 95% CI -1.58, 0.96), externalizing (β: -0.03, 95% CI -1.07, 1.01), internalizing (β: 0.89, 95% CI -0.20, 1.97), or social behaviors (β: -0.04, 95% CI -0.92, 0.84). Somatic complaints were higher in THRT-exposed children (β: 0.98, 95% CI 0.08, 1.87), and children whose mothers were exposed after delivery had more sleep problems than unexposed children (β: 0.99, 95% CI 0.24, 1.74).

CONCLUSIONS

Children prenatally exposed to THRT have developmental outcomes as positive as unexposed children on motor function, communication, and behavior. The association with somatic complaints and sleep were not clinically relevant.

Modeling exposures of medications used episodically during pregnancy: Triptans as a motivating example

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.

Cluster Analysis: A New Approach for Identification of Underlying Risk Factors and Demographic Features of First Trimester Pregnancy Women

Thyroid pathology is reported internationally in 5-10% of all pregnancies. The overall aim of this research was to determine the prevalence of hypothyroidism and risk factors during the first trimester screening in a Mexican patients sample. We included the records of 306 patients who attended a prenatal control consultation between January 2016 and December 2017 at the Women's Institute in Monterrey, Mexico. The studied sample had homogeneous demographic characteristics in terms of age, weight, height, BMI (body mass index) and number of pregnancies. The presence of at least one of the risk factors for thyroid disease was observed in 39.2% of the sample. Two and three clusters were identified, in which patients varied considerably among risk factors, symptoms and pregnancy complications. Compared to Cluster 0, one or more symptoms or signs of hypothyroidism occurred, while Cluster 1 was characterized by healthier patients. When three clusters were used, Cluster 2 had a higher TSH (thyroid stimulating hormone) value and pregnancy complications. There were no significant differences in perinatal variables. In addition, high TSH levels in first trimester pregnancy are characterized by pregnancy complications and decreased newborn weight. Our findings underline the high degree of disease heterogeneity with existing pregnant hypothyroid patients and the need to improve the phenotyping of the syndrome in the Mexican population.

Psychiatric Disorders in the Adolescent Offspring of Mothers with Thyroid Problems During Pregnancy

Maternal thyroid problems during pregnancy have been linked to neurocognitive impairments in children. While studies suggest that disorders of maternal thyroid function during pregnancy are associated with symptoms of mental health problems in children, little is known about the risk of clinically significant psychiatric disorders in adolescence. A sample of 2451 Canadian adolescents enrolled in the Ontario Child Health Study completed the Mini International Neuropsychiatric Interview for Children and Adolescents at 12-17 years of age. Their mothers self-reported thyroid problems during pregnancy. Gestational thyroid problems were associated with offspring oppositional defiant disorder (ODD; OR 3.73; 95% CI 1.69-8.24), conduct disorder (CD; OR 12.95; 95% CI 5.12-32.75), and social anxiety disorder (SAD; OR 6.25; 95% CI 2.53-15.47). Neither sex nor gestational age moderated associations between prenatal thyroid dysfunction and the majority of outcomes. School performance mediated 8% of the association between thyroid problems and SAD, 21% for CD and 53% for ODD.

Safe Expectations: Current State and Future Directions for Medication Safety in Pregnancy Research

Medication use in pregnancy is common, but information about the safety of most medications in pregnant women or their infants is limited. In the absence of data from randomized clinical trials to guide decisions made by regulators, clinicians, and patients, we often have to rely on well-designed observational studies to generate valid evidence about the benefits and risks of medications in pregnancy. Spontaneous reporting, primary case-control and cohort studies, pregnancy exposure registries, and electronic health data have been used extensively for studying medication safety in pregnancy. This article discusses these data sources, their strengths and limitations, and possible strategies and approaches to mitigating limitations when planning studies or interpreting findings from the literature. Strategies discussed include combining data sources across institutional or national borders, developing and using more sophisticated study designs, and taking advantage of existing analytic methods for more complex data structures, such as time-varying exposure or unmeasured confounding. Finally, we make recommendations for study designs that aid in better risk-related communication.

Maternal Thyroid Hormone Replacement Therapy Exposure and Language and Communication Skills of Offspring at 8 Years of Age

IMPORTANCE

Hypothyroidism during pregnancy is associated with neurodevelopmental delays in the offspring. However, it remains unknown whether prenatal thyroid hormone replacement therapy (THRT) has benefits regarding children's language and communication skills.

OBJECTIVE

To quantify associations between prenatal THRT exposure and risk of language impairment diagnosis and parent-reported symptoms of language and communication skill deficits in offspring at 8 years of age.

DESIGN, SETTING, AND PARTICIPANTS

The Norwegian Mother, Father and Child Cohort Study (MoBa), a nationwide population-based cohort study, recruited pregnant women from throughout Norway between June 1999 and December 2008. MoBa was linked to several nationwide registries: the Norwegian Medical Birth Registry, Norwegian Prescription Database, and Norwegian Patient Registry. For this study, the analyzed cohort was restricted to singleton pregnancies resulting in a live-born infant, enrolled in the MoBa between 2005 and 2008. Statistical analysis was performed from January 2 to May 7, 2019.

EXPOSURES

In both study samples, mother-child pairs were categorized into 3 mutually exclusive groups: THRT exposure during pregnancy, based on dispensed prescription records; unexposed to THRT during pregnancy (population comparison); and mothers initiating THRT after delivery (THRT after delivery), comprising incident postpartum THRT users.

MAIN OUTCOMES AND MEASURES

Two defined study samples were analyzed with different outcome measures. In the Norwegian Patient Registry sample, outcome was defined by a diagnosis of language and speech impairment. In the MoBa sample, children were followed up until age 8 years via parental self-completed questionnaires. Hazard ratios were calculated for language impairment diagnosis, estimated by Cox proportional hazards regression. Standardized mean score (β) was calculated for parent-reported symptoms of language and communication deficits, estimated using generalized linear models.

RESULTS

The Norwegian Patient Registry sample included 53 862 mother-child pairs (mean [SD] age, 30.4 [4.6] years; offspring, 26 145 girls and 27 717 boys; 1204 pairs exposed to THRT [2.2%]) and the MoBa sample included 23 686 mother-child pairs (mean [SD] age, 30.8 [4.4] years; offspring, 11 536 girls and 12 150 boys; 532 pairs exposed to THRT [2.2%]). Language and speech impairment diagnosis was not significantly associated with prenatal THRT exposure compared with the unexposed group (adjusted hazard ratio, 0.75; 95% CI, 0.38-1.43) or the THRT after delivery group (adjusted hazard ratio, 0.63; 95% CI, 0.26-1.53). Language outcomes also did not significantly differ between these groups.

CONCLUSIONS AND RELEVANCE

There was no significant difference in child outcomes between children exposed to THRT in the prenatal period compared with children in the population comparison group. These results support current guidelines recommending hypothyroidism treatment during pregnancy. Future research should further examine the use of THRT after delivery or a proper disease comparison group.