Low Apgar score linked to higher incidence of epilepsy

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Newborns with low Apgar scores are more likely to develop epilepsy during childhood and early adulthood than those with higher scores, suggesting that "prenatal or perinatal factors play a larger role in the etiology of epilepsy than has previously been recognized," results of a prospective study in Denmark suggest.

According to Dr. Yuelian Sun, from the University of Aarhus, and associates, clear risk factors have not been identified for most cases of epilepsy. Some research has suggested that early perinatal events may have an effect.

To further explore this concept, Dr. Sun's group identified live newborns born between 1978 and 2002, as documented in the Danish Civil Registration System. Apgar scores at birth were obtained from the Danish Medical Birth Register, and information regarding epilepsy was extracted from the National Hospital Register.

They report in the May issue of Epidemiology that, among the roughly 1.5 million live born children, 16,455 cases of epilepsy were diagnosed by the end of 2002, equivalent to an average incidence rate of 91.7 per 100,000 person-years of follow-up.

Epilepsy incidence increased consistently with decreasing 1- and 5-minute Apgar scores. For example, incidence per 100,000 person-years was 628 for those with 5-minute Apgar scores of 1 to 3, versus 86 for those with scores of 10.

The highest incidence rate ratio associated with Apgar score was 8.03 for children with scores of 1 to 3 at both 1 and 5 minutes compared with children with scores of 10 at both time points. Even when scores improved between 1 and 5 minutes, the infants' risk still remained elevated.

Other factors associated with increased incidence included cerebral palsy, congenital malformations, and parental history of epilepsy. The association between 5-minute Apgar scores and the possibility of epilepsy did not change after excluding patients with these conditions.

The incidence of epilepsy associated with low Apgar score was greatest during the first year of life, but risk remained elevated throughout childhood and up to 25 years of age.

"Potential causal candidates (for these findings) could be infections, maternal lifestyle factors, maternal complications during pregnancy, and factors related to the delivery process," Dr. Sun's team writes. They believe that more research directed to fetal and perinatal origins of epilepsy is warranted.