Maternal and fetal outcomes associated with vagus nerve stimulation during pregnancy

Objective: To access the effect of vagus nerve stimulation (VNS) on the outcome of pregnancy. Methods: We used the International Registry of Antiepileptic Drugs and Pregnancy (EURAP) and its network to search for women receiving adjunctive VNS during pregnancy. Data on maternal and fetal outcomes were extracted from the registry databases and outcomes were evaluated. Results: Twenty-six pregnancies were identified in 25 women. All women were exposed to a relative high VNS stimulation level (mean duty cycle 18%, range 5%-51%). Most women had seizures during pregnancy and almost 70% were on antiepileptic drug (AED) polytherapy. The proportion of women with obstetrical interventions was 53.9% (95% confidence interval [CI] 33.4%-73.4%) which was higher compared to the EURAP average (48.2%; 95% CI 47.2%-49.1%). One infant (3.9%; 95% CI 0.1%-19.6%) was born with a major malformation (unilateral congenital glaucoma), which is within the range expected among offspring of AED-treated women. Conclusion: Although the present series of VNS-exposed pregnancies is the largest reported to date, the sample size is insufficient to draw any firm conclusions on the safety of VNS in pregnancy but the findings suggest an increased rate of obstetrical interventions, and no clear signal of VNS-related teratogenicity.