Pregnancy, antiseizure medications and unexplained intrauterine foetal death.

OBJECTIVE

To assess the role of antiseizure medication (ASM) regimens and other factors in relation to the occurrence of intrauterine foetal death (IUFD) in pregnant women with epilepsy (WWE) enrolled in the Raoul Wallenberg Australian Pregnancy Register of Antiepileptic Drugs (APR).

RESULTS

IUFDs occurred in 70 (3.01 %) of 2,323 prospective pregnancies from WWE with known outcomes in the APR. Factors associated with IUFD occurrence included older maternal age, enrolment in the APR at an earlier stage of pregnancy, history of pregnancies which did not result in livebirths, parental history of foetal malformations, and maternal use of carbamazepine, lamotrigine or ethosuximide. Individual ASM dosages were not associated with IUFD occurrence. Relative to no exposure, the risk of IUFD increased with the increasing number of ASMs used in combination (2 ASMs: relative risk, RR = 5.45 [95 % CI: 0.73-41.80]; 3 ASMs: RR = 10.70 [95 % CI: 1.27-90.17]), >3 ASMs: RR = 10.70 [95 % CI: 1.27-90.17]), but this finding was attenuated after adjusting for other factors implicated in IUFD occurrence. Several ASM pairs were associated with an increased risk of IUFD relative to no exposure, but these associations were lost after accounting for confounders.

CONCLUSIONS

Although it is possible that prenatal ASM exposure may increase the risk of IUFD, other non-pharmacological factors are more relevant to the occurrence to IUFD in pregnant WWE.