Associations between early term and late/post term infants and development of epilepsy: A cohort study

BACKGROUND: While life-long impacts exist for infants born one or two weeks early little evidence exists for those infants born after their due date. However interventions could be used to expedite birth if the risks of continuing the pregnancy are higher than intervening. It is known that the risk of epilepsy in childhood is higher in infants exposed to perinatal compromise and therefore may be useful as a proxy for intrapartum compromise. The aim of this work is to quantify the likelihood of children developing epilepsy based on their gestational age at birth (37–39 weeks or ≥41 weeks). METHODS: The work is based on term infants born in Sweden between 1983 and 1993 (n = 1,030,168), linked to data on disability pension, child mortality and in-patient epilepsy care. The reference group was defined as infants born at 39 or 40 completed weeks of gestation; compared with infants born at early term (37/38 weeks) or late/post term (41 weeks or more). Primary outcome was defined a-priori as a diagnosis of epilepsy before 20 years of age. Secondary outcomes were childhood mortality (before five years of age), and registered for disability pension before 20 years of age. Logistic regression models were used to assess any association of the outcomes with gestational age at birth. FINDINGS: In the unadjusted results, infants born 7 or more days after their due date had higher risks of epilepsy and disability pension than the reference group, but similar risks of child death. Early term infants showed higher risks of epilepsy, disability pension and child death. After adjustment for confounders, there remained a higher risk of epilepsy for both early term (OR 1·19 (1·11–1·29)) and late/post term infants (OR 1·13 (1·06–1·22)). INTERPRETATION: Infants born at 37/38 week or 41 weeks and above, when compared to those born at 39 or 40 weeks gestation, have an increased risk of developing epilepsy. This data could be useful in helping women and care givers make decisions with regard to the timing of induction of labour.