Development and Validation of Algorithms to Estimate Live Birth Gestational Age in Medicaid Analytic eXtract Data

Prescription medication use during pregnancy in the United States from 2011 to 2020: trends and safety evidence

BACKGROUND

Medication use during pregnancy has increased in the United States despite the lack of safety data for many medications.

OBJECTIVE

This study aimed to inform research priorities by examining trends in medication use during pregnancy and identifying gaps in safety information on the most commonly prescribed medications.

STUDY DESIGN

We identified population-based cohorts of commercially (MarketScan 2011-2020) and publicly (Medicaid Analytic eXtract/Transformed Medicaid Statistical Information System Analytic Files 2011-2018) insured pregnancies ending in live birth from 2 health care utilization databases. Medication use was based on filled prescriptions between the date of last menstrual period through delivery, as well as the period before the last menstrual period and during specific trimesters. We also included a cross-sectional representative sample of pregnancies ascertained by the National Health and Nutrition Examination Survey (2011-2020), with information on prescription medication use during the preceding month obtained through maternal interviews. Teratogen Information System was used to classify the available evidence on teratogenic risk.

RESULTS

Among over 3 million pregnancies, the medications most commonly dispensed at any time during pregnancy were analgesics, antibiotics, and antiemetics. The top medications were ondansetron (16.8%), amoxicillin (13.5%), and azithromycin (12.4%) in MarketScan, nitrofurantoin (22.2%), acetaminophen (21.3%; mostly as part of acetaminophen-hydrocodone products), and ondansetron (19.5%) in Medicaid Analytic eXtract/Transformed Medicaid Statistical Information System Analytic Files, and levothyroxine (5.0%), sertraline (2.9%), and insulin (2.9%) in the National Health and Nutrition Examination Survey group. The most commonly dispensed suspected teratogens during the first trimester were antithyroid medications. The use of antidiabetic and psychotropic medications has continued to increase in the United States during the last decade, opioid dispensation has decreased by half, and antibiotics and antiemetics continue to be common. For one-quarter of medications, there is insufficient evidence available to characterize their safety profile in pregnancy.

CONCLUSION

There is a need for more drug research in pregnant patients. Future research should focus on anti-infectives with high utilization and limited level of evidence on safety for use during pregnancy. Although lack of evidence is not evidence of safety concerns, it does not indicate risk either. In many instances, the benefits outweigh the risks when these medications are used clinically, and some of the medications with no proven safety may be necessary to treat patients.

Use of Real-World Data and Machine Learning to Screen for Maternal and Paternal Characteristics Associated with Cardiac Malformations

Effective prevention of cardiac malformations, a leading cause of infant morbidity, is constrained by limited understanding of etiology. The study objective was to screen for associations between maternal and paternal characteristics and cardiac malformations. We selected 720,381 pregnancies linked to live-born infants (n=9,076 cardiac malformations) in 2011-2021 MarketScan US insurance claims data. Odds ratios were estimated with clinical diagnostic and medication codes using logistic regression. Screening of 2,000 associations selected 81 associated codes at the 5% false discovery rate. Grouping of selected codes, using latent semantic analysis and the Apriori-SD algorithm, identified elevated risk with known risk factors, including maternal diabetes and chronic hypertension. Less recognized potential signals included maternal fingolimod or azathioprine use. Signals identified might be explained by confounding, measurement error, and selection bias and warrant further investigation. The screening methods employed identified known risk factors, suggesting potential utility for identifying novel risk factors for other pregnancy outcomes.

Prenatal Care Initiation and Exposure to Teratogenic Medications

Importance

With new legal abortion restrictions, timing of prenatal care initiation is critical to allow for discussion of reproductive options among pregnancies exposed to teratogenic medications.

Objective

To investigate the prevalence of prenatal exposure to teratogenic medications and prenatal care initiation across gestational weeks.

Design, Setting, and Participants

This descriptive, population-based cross-sectional study used health encounter data from a national sample of individuals with employer-sponsored health insurance. A validated algorithm identified pregnancies among persons identifying as female that ended with a live or nonlive outcome between January 2017 and December 2019. Data were analyzed from December 2022 to December 2023.

Exposures

Prenatal exposure to any of 137 teratogenic medications, measured via pharmacy and medical claims. Measurement of prenatal care initiation was adapted from the Children's Health Care Quality Measures.

Main Outcomes and Measures

Prevalence of prenatal exposure to teratogens and prenatal care initiation by gestational week. Timing of prenatal teratogenic exposure was compared with timing of prenatal care initiation and legal abortion cutoffs.

Results

Among 639 994 pregnancies, 472 472 (73.8%; 95% CI, 73.7%-73.9%) had a live delivery (mean [SD] age, 30.9 [5.4] years) and 167 522 (26.2%; 95% CI, 26.1%-26.3%) had a nonlive outcome (mean [SD] age, 31.6 [6.4] years). Of pregnancies with live deliveries, 5.8% (95% CI, 5.7%-5.8%) were exposed to teratogenic medications compared with 3.1% (95% CI, 3.0%-3.2%) with nonlive outcomes. Median time to prenatal care was 56 days (IQR, 44-70 days). By 6 weeks' gestation, 8186 pregnancies had been exposed to teratogenic medications (25.2% [95% CI, 24.7%-25.7%] of pregnancies exposed at any time during gestation; 1.3% [95% CI, 1.3%-1.3%] of all pregnancies); in 6877 (84.0%; 95% CI, 83.2%-84.8%), prenatal care was initiated after 6 weeks or not at all. By 15 weeks, teratogenic exposures had occurred for 48.9% (95% CI, 48.4%-49.5%) of all teratogen-exposed pregnancies (2.5% [2.4-2.5] of all pregnancies); prenatal care initiation occurred after 15 weeks for 1810 (16.8%; 95% CI, 16.1%-17.5%) with live deliveries and 2975 (58.3%; 95% CI, 56.9%-59.6%) with nonlive outcomes. Teratogenic medications most used within the first 15 gestational weeks among live deliveries included antiinfectives (eg, fluconazole), anticonvulsants (eg, valproate), antihypertensives (eg, lisinopril), and immunomodulators (eg, mycophenolate). For nonlive deliveries, most antihypertensives were replaced by vitamin A derivatives.

Conclusions and Relevance

In this cross-sectional study, most exposures to teratogenic medications occurred in early pregnancy and before prenatal care initiation, precluding prenatal risk-benefit assessments. Prenatal care commonly occurred after strict legal abortion cutoffs, prohibiting consideration of pregnancy termination if concerns about teratogenic effects arose.

Accounting for Twins and Other Multiple Births in Perinatal Studies Conducted Using Healthcare Administration Data

The analysis of perinatal studies is complicated by twins and other multiple births even when they are not the exposure, outcome, or a confounder of interest. Common approaches to handling multiples in studies of infant outcomes include restriction to singletons, counting outcomes at the pregnancy-level (i.e., by counting if at least one twin experienced a binary outcome), or infant-level analysis including all infants and, typically, accounting for clustering of outcomes by using generalised estimating equations or mixed effects models. Several healthcare administration databases only support restriction to singletons or pregnancy-level approaches. For example, in MarketScan insurance claims data, diagnoses in twins are often assigned to a single infant identifier, thereby preventing ascertainment of infant-level outcomes among multiples. Different approaches correspond to different causal questions, produce different estimands, and often rely on different assumptions. We demonstrate the differences that can arise from these different approaches using Monte Carlo simulations, algebraic formulas, and an applied example. Furthermore, we provide guidance on the handling of multiples in perinatal studies when using healthcare administration data.

Common teratogenic medication exposures-a population-based study of pregnancies in the United States

BACKGROUND

Risk mitigation for most teratogenic medications relies on risk communication via drug label, and prenatal exposures remain common. Information on the types of and risk factors for prenatal exposures to medications with teratogenic risk can guide strategies to reduce exposure.

OBJECTIVE

This study aimed to identify medications with known or potential teratogenic risk commonly used during pregnancy among privately insured persons.

STUDY DESIGN

We used the Merative™ MarketScan® Commercial Database to identify pregnancies with live or nonlive (ectopic pregnancies, spontaneous and elective abortions, stillbirths) outcomes among persons aged 12 to 55 years from 2011 to 2018. Start/end dates of medication exposure and pregnancy outcomes were identified via an adapted algorithm based on validation studies. We required continuous health plan enrollment from 90 days before conception until 30 days after the pregnancy end date. Medications with known or potential teratogenic risk were selected from TERIS (Teratogen Information System) and drug monographs based on the level of risk and quality of evidence (138 with known and 60 with potential risk). We defined prenatal exposure on the basis of ≥1 outpatient pharmacy claim or medical encounter for medication administration during target pregnancy periods considering medication risk profiles (eg, risk only in the first trimester or at a certain dose threshold). Sex hormones and hormone analogs, and abortion and postpartum/abortion hemorrhage treatments were not considered as teratogenic medications because of challenges in separating pregnancy-related indications, nor were opioids (because of complex risk-benefit considerations) or antiobesity medications if their only teratogenic mechanism was weight loss.

RESULTS

Among all pregnancies, the 10 medications with known teratogenic risk and the highest prenatal exposures were sulfamethoxazole/trimethoprim (1988 per 100,000 pregnancy-years), high-dose fluconazole (1248), topiramate (351), lisinopril (144), warfarin (57), losartan (56), carbamazepine (50), valproate (49), vedolizumab (28 since 2015), and valsartan (25). Prevalence of exposure to sulfamethoxazole/trimethoprim decreased from 2346 to 1453 per 100,000 pregnancy-years from 2011 to 2018, but prevalence of exposure to vedolizumab increased 6-fold since its approval in 2015. Prenatal exposures in the first trimester were higher among nonlive pregnancies than among live-birth pregnancies, with the largest difference observed for warfarin (nonlive 370 vs live birth 78), followed by valproate (258 vs 86) and topiramate (1728 vs 674). Prenatal exposures to medications with potential teratogenic risk were most prevalent for low-dose fluconazole (6495), metoprolol (1325), and atenolol (448). The largest first-trimester exposure differences between nonlive and live-birth pregnancies were observed for lithium (242 vs 89), gabapentin (1639 vs 653), and duloxetine (1914 vs 860). Steady increases in hydralazine and gabapentin exposures were observed during the study years, whereas atenolol exposure decreased (561 to 280).

CONCLUSION

Several medications with teratogenic risk for which there are potentially safer alternatives continue to be used during pregnancy. The fluctuating rates of prenatal exposure observed for select teratogenic medications suggest that regular reevaluation of risk mitigation strategies is needed. Future research focusing on understanding the clinical context of medication use is necessary to develop effective strategies for reducing exposures to medications with teratogenic risk during pregnancy.

Distribution of gestational age at birth by maternal and infant characteristics in U.S. birth certificate data: Informing gestational age assumptions when clinical estimates are not available

PURPOSE

We aimed to describe the distribution of gestational age at birth (GAB) to inform the estimation of GAB when clinical or obstetric estimates are not available for perinatal pharmacoepidemiology studies.

METHODS

We estimated GAB (median, mode, mean, and standard deviation) and percentage born at each gestational week in groups based on plurality and other variables for live births in CDC's U.S. birth data.

RESULTS

In 2020, 3 617 213 newborns had birth certificates with nonmissing GAB. Among singletons (3 501 693), median and mode GAB were both 39 weeks. Births with lower median GAB were from women with eclampsia (37 weeks) or receiving intensive care (37 weeks); newborns receiving intensive care (37 weeks); newborns with birth weight <2500 g (35 weeks), <1500 g (28 weeks), or <1000 g (25 weeks); and newborns not discharged alive (23 weeks). Among twins (112 633), median GAB was 36 weeks (mode, 37 weeks). Additional noteworthy groups were women with 0-6 prenatal visits (median, 34 weeks) or 7-8 prenatal visits (median, 35 weeks) or aged 15-19 years (median, 35 weeks).

CONCLUSIONS

Some maternal and infant groups had distinct GAB distributions in the United States. This information can be useful in estimating GAB when individual-level clinical estimates are not available, such as in database studies of medication use during pregnancy.