Preeclampsia associated with epilepsy in offspring, data show

Preeclampsia, like eclampsia, increases the risk for epilepsy in offspring, but this increased risk only seems to be significant among children born after 37 weeks of gestation, suggest findings from a population-based cohort study conducted in Denmark. Investigators evaluated the association between preeclampsia or eclampsia and the incidence rate ratio (IRR) of epilepsy in >1.5 million children born between Jan. 1, 1978, and Dec. 2, 2004, with information collected from national...

Preeclampsia, like eclampsia, increases the risk for epilepsy in offspring, but this increased risk only seems to be significant among children born after 37 weeks of gestation, suggest findings from a population-based cohort study conducted in Denmark.

Investigators evaluated the association between preeclampsia or eclampsia and the incidence rate ratio (IRR) of epilepsy in >1.5 million children born between Jan. 1, 1978, and Dec. 2, 2004, with information collected from national registries.

Within the cohort, 2.94% of children were prenatally exposed to preeclampsia, and 0.04% were prenatally exposed to eclampsia. A total of 20,260 children developed epilepsy during up to 27 years of follow-up.

In unadjusted analyses, the IRR for epilepsy was 1.27 among the children exposed to mild preeclampsia (n=34,823), 1.54 among those exposed to severe preeclampsia (n=7,043), and 1.78 among those exposed to eclampsia (n=654) relative to those with no such exposures. In analyses adjusted for the child's sex, gestational age, parity, maternal age, maternal history of epilepsy, and calendar year, the respective IRRs were 1.20 (95% CI, 1.11-1.30), 1.14 (95% CI, 0.96-1.36), and 1.35 (95% CI, 0.81-2.24). The relationship between mild preeclampsia, for which there were the most exposures, and epilepsy remained significant.

These results changed only slightly when the children with cerebral palsy, congenital malformations, or an Apgar score <7 were excluded from the analysis, the authors noted.

When the children were stratified by gestational age, results showed that the relationship between preeclampsia and epilepsy was only significant among the children born at term (37-41 weeks of gestation) or postterm (>=42 weeks of gestation). Among the children born postterm, those exposed to mild preeclampsia had an IRR for epilepsy of 1.68 (95% CI, 1.31-2.16) relative to those with no exposure to preeclampsia, while those exposed to severe preeclampsia had an IRR of 2.57 (95% CI, 1.07-6.19). The corresponding IRRs for the children born at term were 1.16 (95% CI, 1.06-1.27) and 1.41 (95% CI, 1.12-1.79).

The adjusted IRRs for epilepsy after exposure to eclampsia were 5.03 (95% CI, 1.26-20.14) among the children born postterm and 1.29 (95% CI, 0.64-2.57) among the children born at term.

Among the children born at term or later, those exposed to preeclampsia who were also small for their gestational age (SGA) had the greatest risk of developing epilepsy. Both preeclampsia and SGA were independent risk factors for epilepsy, the authors noted.

"Preeclampsia or its related pathologies may increase the susceptibility to epilepsy later in life, or preeclampsia and epilepsy may also share common causative factors," the study authors postulated. (Wu CS, et al. Pediatrics 2008;122:1072-1078.)