The risk of seizure‐affected pregnancy in Australian women with epilepsy

Abstract Objective We reported earlier that the occurrence of seizures in the pre‐pregnancy year was the main determinant of the following pregnancy being seizure‐affected. Additional risk factors were assessed in this study. Methods The pregnancies involved first pregnancies of women with epilepsy . Two categories were compared. One category comprised 711 pregnancies in which seizures had occurred during the pre‐pregnancy year and where seizures might reasonably be expected to continue to occur during the 9 months involved in any following pregnancy. The other category contained 634 pregnancies that were seizure‐free in the pre‐pregnancy year. Multivariate logistic regressions were fitted for 1345 subjects for seizure occurrence during pregnancy for co‐variates listed to identify statistically seizure‐related co‐variates. Results Seizure‐affected pregnancy rates in the 1345 pregnancies studied remained stable over the consecutive 5‐year intervals from 1999 onwards, viz. 50.5%, 53.9%, 50.3%, 52.8% and 48.2%. Seizure‐affected pregnancy was more likely in WWE, who had: (1) Shorter durations of pre‐pregnancy freedom from seizures. (2) Focal epilepsy. (3) Not taken ASMs while pregnant. (4) Not used pre‐pregnancy folate supplementation. (5) Longer durations of epilepsy. (6) Earlier age onset of epilepsy. The hazard of a seizure‐affected next pregnancy was over threefold higher when the pre‐pregnancy year was seizure‐affected than when it had been seizure‐free. Significance The finding that a year's pre‐pregnancy seizure freedom was associated with a reduced risk of seizures in the next pregnancy was expected. The magnitude of the greater than threefold higher seizure risk in the next pregnancy if seizures had occurred in the pre‐pregnancy year was not. It identifies a group of women with epilepsy whose medical management during pregnancy warrants particular care.