Infants with short gestational age, low birth weight and intrauterine growth restriction are associated with an increased risk of epilepsy. Previous studies have had conflicting findings regarding the relationship between epilepsy and birth weight or gestational age. To investigate further, researchers in Denmark studied 1.4 million babies born in Denmark between 1979 and 2002, and then followed up to 24 years of age. Epilepsy cases were identified through the Danish National Hospital Register. Among these, 14,334 were hospitalised with epilepsy at some point over the follow-up period. The rate of epilepsy diagnosis increased consistently with decreasing gestational age and birth weight. However, the association became weaker as the age at epilepsy diagnosis increased. It was found that epilepsy in the first year of life was more than five times more frequent among infants with a gestational age of 22–32 weeks at birth compared with those with a gestational age of 39–41 weeks at birth. Similarly, the occurrence rate was five-fold higher among children whose birth weight was less than 2000 grams compared to those whose birth weight was between 3000 and 3900 grams. The findings indicate a strong association of low birth weight and short gestational age with the risk of epilepsy within the first five years of life. This could be because the immature brain is more susceptible to seizures when exposed to risk factors operating during prenatal life than the mature brain is.
American Journal of Epidemiology,
February 2008