Preeclampsia and Risk for Epilepsy in Offspring

Among women who develop preeclampsia during pregnancy, an increased risk of epilepsy is present in children who are born full term or post term, according to a report in the November 2008 issue of Pediatrics. The average length of a pregnancy is 40 weeks; birth at 37-41 weeks is considered full term; and birth after 42 weeks is considered post term. 

Preeclampsia, a condition that develops after the 20th week of pregnancy, is characterized by high blood pressure and protein in the urine. The best treatment is to deliver the infant. If this is not possible, bed rest, close monitoring and delivery as soon as survival outside of the uterus is likely is recommended, preferably after the 37th week of pregnancy. 

Prior research has identified eclampsia as a strong risk factor for epilepsy in offspring, but whether the same held true with preeclampsia was unclear, Dr. Chun Sen Wu, with the University of Aarhus, Denmark, and colleagues explain. Eclampsia occurs when pre-eclampsia worsens and is characterized by seizures, agitation and unconsciousness. Eclampsia is considered a medical emergency and jeopardizes the life of the mother and child. Magnesium sulfate is sometimes given to women with preeclampsia to help prevent progression to eclampsia.

The researchers reviewed data from the Danish National Hospital Register containing 1.5 million infants born from 1978 to 2003. From these data, the research team identified 45,288 (2.9 percent) children exposed to preeclampsia and 654 (0.04 percent) exposed to eclampsia. The preeclampsia group comprised 34,823 children exposed to mild preeclampsia and 7,043 exposed to severe preeclampsia, and in 3,422 cases, the severity was not specified.
The researchers found that 20,620 of the subjects in the entire cohort developed epilepsy during follow-up of up to 27 years.

However, maternal preeclampsia increased the incidence of epilepsy in the children born term or post term. With mild preeclampsia, the incidence rate of epilepsy rate was increased by approximately 20 percent, but was more marked in the post-term group with a 68 percent increase in the incidence rate for epilepsy. In the severe preeclampsia group, the percent for full-term and post-term infants increased by 41 percent and 157 percent, respectively. Newborns that were small for gestational age were also at risk for developing epilepsy, independent of whether the mothers had preeclampsia.

Consistent with previous reports, eclampsia was associated with a stronger risk of epilepsy. In contrast, preeclampsia was not linked to epilepsy in preterm infants, the report indicates. 

The authors conclude that "preeclampsia or its related pathologies may increase the susceptibilities to epilepsy later in life, or preeclampsia and epilepsy may also share common causative factors."

SOURCE: Pediatrics, November 2008 & Reuters Health

Note: This clinical population-based study indicates that there may be an association between maternal preeclampsia and the development of epilepsy in their children. However, the overall risk of the offspring developing epilepsy was still quite low, at approximately 105-136 per 100,000 person-years for the group with preeclampsia compared to 95 per 100,000 person-years for the group without preeclampsia. The lack of a positive association for the children born premature is likely due to the fact that prematurity and its associated complications outweigh any risks conferred by preeclampsia.

Perhaps the most useful aspect of this study is identification of a prenatal factor that can contribute to the risk for developing epilepsy. Any clues about the underlying mechanisms that contribute to the development of epilepsy can provide new insights and help guide future research strategies.

These findings are also encouraging because they identify a prenatal factor that can be modified, thereby potentially reducing the risk for epilepsy in the offspring. Preeclampsia and eclampsia occur more commonly in women with poor prenatal care, and occur more commonly in developing countries. This study helps to further emphasize the importance of good prenatal care, careful observation during pregnancy and aggressive management if signs of preeclampsia appear, and close observation of the offspring, as needed.–Page Pennell, M.D., director, Emory Epilepsy Program and Epilepsy Foundation Professional Advisory Board chair-elect