Specific Birth Defects Following Antiseizure Medications Used By Pregnant Women With Epilepsy.

Background and objectives: Previous research has been limited in the comprehensive study of associations between the use of individual antiseizure medications (ASMs) in pregnancy and specific groups of birth defects, and systematic reviews and meta-analyses on the topic are limited by pooled samples and study designs. This study investigated birth defects related to ASM use in pregnancy in children born to women with epilepsy in Sweden over 20 years.

Methods: We used data from Swedish national registers to follow a cohort of 17,996 children born to women diagnosed with epilepsy any time before conception in Sweden from 1996 to 2016, following them through 2017. We examined maternal-reported use of the 4 most commonly reported ASMs: lamotrigine (n = 2,148, 11.9%), carbamazepine (n = 1,940, 10.8%), valproic acid (n = 1,043, 5.80%), and levetiracetam (n = 587, 3.26%). We identified birth defects using diagnoses recorded at the time of discharge from the hospital and inpatient and outpatient diagnoses recorded in the first year of life. Models were estimated in a stepped fashion: unadjusted, adjusted for covariates, among a subcohort born to women diagnosed 10 years before conception (n = 14,586), and restricted to monotherapy.

Results: Valproic acid use in pregnancy had the strongest and most widespread associations with birth defects in children, with carbamazepine also having links to several birth defects, including respiratory system and genital organ defects. Lamotrigine use in pregnancy was associated with cleft lip/palate and chromosomal abnormalities. Levetiracetam was most often used with other ASMs and preliminarily associated with many birth defects.

Discussion: Our findings support avoidance of valproic acid use in pregnancy whenever possible. Lamotrigine and carbamazepine may be safer alternatives. However, these medications were also associated with certain birth defects, including some not reported previously. We are among the first to examine the possible effects of levetiracetam use in pregnancy, though more research is needed to investigate this further.