No abstract

Importance: Evidence for the fetal safety of ondansetron, a 5-HT3 receptor antagonist that is commonly prescribed for nausea and vomiting in pregnancy, is limited and conflicting. Objective: To evaluate the association between ondansetron exposure during pregnancy and risk of congenital malformations. Design, Setting, and Participants: A retrospective cohort study nested in the 2000–2013 nationwide Medicaid Analytic eXtract. The cohort consisted of 1,816,414 pregnancies contributed by 1,502,895 women enrolled in Medicaid from 3 months before the last menstrual period through ≥1 month after delivery; infants were enrolled in Medicaid for ≥3 months after birth. The final date of follow-up was December 31, 2013. Propensity score stratification was used to control for treatment indication and other confounders. Exposure: Ondansetron dispensing during the first trimester, the period of organogenesis. Main Outcome(s) and Measure(s): Primary outcomes were cardiac malformations and oral clefts diagnosed during the first 90 days after delivery. Secondary outcomes included congenital malformations overall and subgroups of cardiac malformations and oral clefts. Results: Among 1,816,414 pregnancies (mean age, 24.3 [5.8] years), 88,467 (4.9%) were exposed to ondansetron during the first trimester. Overall, 14,577 of 1,727,947 unexposed and 835 of 88,467 exposed infants were diagnosed with a cardiac malformation, for an absolute risk of 84.4 (95% CI, 83.0 – 85.7) and 94.4 (88.0 – 100.8) per 10,000 births respectively. The absolute risks of oral clefts were 11.1 (10.6 – 11.6) and 14.0 (11.6 – 16.5) per 10,000 (1,912 unexposed and 124 exposed cases); and the risks of any congenital malformation were 370.4 (358.0 – 382.9) and 313.5 (310.9 – 316.1) per 10,000 (3,277 exposed and 54,174 unexposed cases). The adjusted relative risk (RR) for cardiac malformations was 0.99 (95% CI, 0.93 – 1.06) and the adjusted risk difference (RD) was −0.8 (−7.3 – 5.7 per 10,000 births). For oral clefts, the adjusted RR was 1.24 (1.03 – 1.48) and the RD was 2.7 (0.2 – 5.2 per 10,000 births). The adjusted estimate for congenital malformations overall was RR = 1.01 (0.98 – 1.05) and RD = 5.4 (−7.3 – 18.2 per 10,000 births). Conclusions and Relevance: Among offspring of mothers enrolled in Medicaid, first-trimester exposure to ondansetron was not associated with cardiac malformations or congenital malformations overall after accounting for measured confounders, but was associated with a small increased risk of oral clefts.

Background Hydroxychloroquine (HCQ) is generally considered safe in pregnancy for the treatment of rheumatic conditions, but studies have been too small to evaluate teratogenicity. Quantifying the risk of congenital malformations associated with early pregnancy exposure to HCQ is important both in the context of its ongoing use for rheumatological disorders as well as its potential future use for COVID-19 prophylaxis, for which a number of clinical trials are ongoing despite initial trials for COVID-19 treatment having been negative. Objective The study objective was to evaluate the risk of major congenital malformations associated with exposure to HCQ during the first trimester, the period of organogenesis. Study Design We performed a population-based cohort study nested in the Medicaid Analytic eXtract (MAX, 2000-2014) and IBM MarketScan Research Database (MarketScan, 2003-2015). The source cohort included 2,045 HCQ exposed and 3,198,589 unexposed pregnancies continuously enrolled in their respective insurance program from 3 months before the last menstrual period through at least one month after delivery; infants were enrolled for at least 3 months after birth. We compared the risk of congenital malformations in women with HCQ use during the first trimester versus no use, restricting the cohort to women with rheumatic disorders and using propensity score matching to control for indication, demographics, medical comorbidities, and concomitant medications (N= 1,867 HCQ exposed; 19,080 unexposed pregnancies). The outcomes considered included major congenital malformations diagnosed during the first 90 days after delivery, and specific malformation types for which there were at least 5 exposed events: oral clefts, cardiac, respiratory, gastrointestinal, genital, urinary, musculoskeletal, and limb defects. Results Overall, 54.8 per 1,000 infants exposed to HCQ were born with a major congenital malformation versus 35.3 per 1,000 unexposed infants, corresponding to an unadjusted relative risk of 1.51 (95% CI, 1.27–1.81). Patient characteristics were balanced in the restricted, propensity score matched cohort. The adjusted relative risk was 1.26 (1.04–1.54); it was 1.33 (1.08-1.65) for a daily dose ≥400mg and 0.95 (0.60-1.50) for <400mg. Among the different malformation groups considered, more substantial increases in the risk for oral clefts, respiratory anomalies and urinary defects were observed, although estimates were imprecise. No pattern of malformations was identified. Conclusions Our findings suggest a small increase in the risk of malformations associated with first trimester HCQ use. For most patients with autoimmune rheumatic disorders, the benefits of treatment during pregnancy will likely outweigh this risk. If HCQ were shown to be effective for COVID-19 prophylaxis in ongoing trials, the risk of malformations would need to be balanced against such benefits.