Is Topamax (Topiramate) Safe During Pregnancy?

What does the evidence say about topamax during pregnancy?

1. Topiramate use in the first trimester might increase the chance of certain birth defects such as cleft lip with or without cleft palate, though not every study has found an increased risk, reflecting some inconsistency in the evidence. 1
2. A pooled analysis of two major birth defects studies found an odds ratio of about 5.36 for cleft lip and palate with first-trimester topiramate monotherapy, which the authors translate into an absolute risk of roughly 5 per 1,000 topiramate-exposed pregnancies, compared with about 1 per 1,000 in the general population. 2
3. A separate study of ten antiepileptic drugs found topiramate associated with an odds ratio of 6.8 for cleft lip with or without cleft palate, one of only two drugs in the group showing a significant malformation-risk signal, while several other antiepileptic drugs in the same study showed no significant association. 3
4. Using topiramate at the same time as hormonal contraceptive medications can make the contraceptive less effective, so anyone on topiramate who is using or considering hormonal birth control should talk with their provider about this interaction. 4
5. Topiramate passes into breastmilk in small amounts; available information describes doses up to 200 mg a day being used by nursing mothers. 1

Is topamax safe in each trimester?

• First trimester. First-trimester exposure is when the oral clefts risk applies, since this is when the lip and palate are forming. Pooled research puts the risk at roughly 5 per 1,000 exposed pregnancies, compared with about 1 per 1,000 in the general population, though the number of cases studied is still fairly small.
• Second trimester. By the second trimester, the cleft-related window has passed, since the lip and palate finish forming earlier in pregnancy. If you're taking topiramate for migraine prophylaxis or a seizure disorder, this is a good time to confirm your dose and plan with your provider, since seizure or migraine control still matters.
• Third trimester. In the third trimester, ongoing management with your neurology or headache provider stays important, and it's worth discussing a plan for feeding and monitoring with your pediatric team, since topiramate does pass into breastmilk in small amounts if you plan to breastfeed.