Objective:

To describe safety and clinical outcomes of vagus nerve stimulator (VNS) treatment during pregnancy in patients with epilepsy.

Background:

The vagus nerve plays an important role in uterine blood flow and contraction. The literature describing the effect of VNS on pregnancy is limited.

Design/Methods:

In this retrospective study, Mayo Clinic electronic medical records of VNS implantations for drug-resistant epilepsy from January 2002-April 2023 were searched to identify women who were pregnant with VNS. Charts of those identified were reviewed to extract data about maternal epilepsy, VNS treatment, and pregnancy.

Results:

Of 447 patients who underwent VNS implantation, 230 (51.5%) were females. There were 13 pregnancies of 9 patients. Seven were responders to VNS. VNS mean amplitude prior to pregnancy was 1 mA (range 0.5 mA to 1.5 mA). The mean age at the time of delivery was 30.5 years (range 21 to 39) and all patients were on antiseizure medications with 7 patients on more than one (mean 2, range 1 to 3). During 4 pregnancies, there was an exacerbation in seizure frequency requiring escalation of antiseizure medications, and VNS therapy was escalated in 2. Of the 13 pregnancies, one miscarriage occurred, and 7 pregnancies were characterized by additional complications, including gestational diabetes (2), severe pre-eclampsia and fetal growth restriction (FGR) requiring preterm delivery (1), FGR requiring preterm delivery (1), arrest of dilation during labor requiring cesarean section (1), and significant seizure exacerbation requiring hospitalization (1). Ten deliveries occurred at term. The average birth weight was 2.904 kg. There were no major congenital malformations (MCMs) identified.

Conclusions:

In this small series, there were no MCMs due to VNS teratogenesis. The pregnancy complications observed are consistent with complications previously described during pregnancy in patients with epilepsy. However, given the limited available data, further studies are needed.