Bupropion

Pregnancy

Birth defects: MotherToBaby's 1 January 2026 sheet says bupropion is not expected to increase overall birth-defect chances and notes two small first-trimester studies with possible heart-defect signals. The sheet also reports that other studies did not find an overall increase, including heart defects. Cole et al. (2007) studied 1,213 first-trimester exposures; overall malformations were 23.1 per 1,000 and the adjusted odds ratio was 0.95 (95% CI 0.62-1.45) versus other antidepressants. Alwan et al. (2010), a case-control study with 6,853 infants with heart defects and 5,869 controls, found an association with left outflow tract defects (aOR 2.6, 95% CI 1.2-5.7); the label reports 10 exposed cases. Louik et al. (2014) found a ventricular septal defect signal, especially for bupropion alone (aOR 2.5, 95% CI 1.3-5.0; 17 exposed cases reported in the label), but did not confirm the earlier left-sided signal. The Wellbutrin XL label says overall cardiovascular-malformation risk was not increased and specific left outflow tract and ventricular septal defect findings are inconsistent, based on small case counts, and possibly due to chance from multiple comparisons. Miscarriage: MotherToBaby says the evidence is limited and cites one study in which the chance was similar to that with other depression medicines. Chun-Fai-Chan et al. (2005) followed 136 first-trimester exposures and reported 20 spontaneous abortions among the exposed pregnancies; the study found more spontaneous abortions than in its non-teratogen comparison group, but rates were similar to other antidepressant studies. Other pregnancy outcomes: MotherToBaby says bupropion is not expected to increase preterm delivery or low birth weight. A 2019 review included 18 studies, including 14 bupropion pregnancy studies, but described study quality as variable and evidence as poor. Its pooled estimates were mean birth weight 3,305.9 g and mean gestational age 39.2 weeks, with substantial between-study variation; these pooled averages do not establish a trimester-specific effect. Tran et al. (2025) studied 1,042 first-trimester bupropion exposures for smoking cessation in Australia and New Zealand and found no increase in major malformations overall versus pregnant smokers without pharmacotherapy (35.5 vs 38.8 per 1,000 live births; aRR 0.93, 95% CI 0.67-1.29). This population and indication should not be treated as a study of bupropion prescribed for depression. Child development: MotherToBaby says the effect on future behavior or learning is unknown and notes one small ADHD study with confounding limits. Peeples et al. (2026) analyzed electronic health records for 6,135,213 children born from 2014 to 2023. Figure 3 lists the bupropion row as 5,128 / 98,507 (5.2%) and an adjusted hazard ratio for autism diagnoses of 1.57 (95% CI 1.53-1.61) versus pregnancies without any of the studied medications. This is an observational association, not evidence that bupropion caused autism. The study lacked dose and duration data and did not independently confirm autism diagnoses, among other limitations.

Breastfeeding

LactMed's 15 January 2026 review reports low milk levels with maternal doses up to 300 mg daily, but little reported use in newborns and possible seizures in partially breastfed 6-month-olds. Haas et al. (2004) measured bupropion and active metabolites in milk from 10 postpartum volunteers; LactMed estimates average infant exposure at 0.2% of the maternal weight-adjusted dose for bupropion alone and 2% for bupropion plus metabolites. The volunteers pumped and discarded milk during the study, so it measured milk exposure rather than infant outcomes. MotherToBaby reports two seizure cases in 6-month-old infants exposed through milk. Primary case reports include a 2004 possible seizure report and a 2014 report involving bupropion with escitalopram; the latter cannot separate the effects of the two medicines. LactMed says bupropion alone is not a reason to discontinue breastfeeding, but another medicine may be preferred for a newborn or preterm infant, and infants exposed to bupropion with an SSRI should be closely monitored for vomiting, diarrhea, jitteriness, or sedation.

What was tested

Pregnancy evidence includes first-trimester case-control and retrospective insurance-cohort studies, a prospective comparative study, a review of pregnancy studies, prescription-record newborn cohorts, and a four-country cohort limited to smoking-cessation exposures. The studies are observational or use prescription records, so they can be affected by confounding and may not confirm that the medicine was taken. Some cardiac-defect estimates rely on small exposed case counts. Newborn studies use different outcomes, including poor neonatal adaptation, adaptation syndrome, and NICU admission, and different comparison groups. Breastfeeding evidence includes small milk-level studies, limited infant follow-up, observational data, and case reports. The studies reviewed do not provide randomized estimates of outcomes separately for each trimester.