Fetal growth retardation and risk of febrile seizures.

Objective: The goal was to examine the associations between fetal growth characteristics in different trimesters of pregnancy and the occurrence of febrile seizures in early childhood.

Methods: This study was embedded in a population-based, prospective, cohort study from early fetal life onward. Fetal growth characteristics (femur length, abdominal circumference, estimated fetal weight, head circumference, biparietal diameter, and transverse cerebellar diameter [TCD]) were measured with ultrasonography in the second and third trimesters of pregnancy. Information on the occurrence of febrile seizures was collected with questionnaires at the ages of 12 and 24 months. Analyses were based on data for 3372 subjects.

Results: In the second trimester, children in the lowest tertile of TCDs were at increased risk of developing febrile seizures, compared with children in the highest tertile (odds ratio 2.87 [95% confidence interval: 1.31-6.28]). In the third trimester, children in the lowest tertile of all general growth characteristics (femur length, abdominal circumference, and estimated fetal weight) were at increased risk of developing febrile seizures. This association was strongest for children in the lowest tertile of estimated fetal weight (odds ratio: 2.57 [95% confidence interval: 1.34-4.96]). Children in the lowest tertile of biparietal diameter in the third trimester also were at increased risk of febrile seizures. Similar but not statistically significant tendencies were observed for head circumference and TCD.

Conclusions: Fetal growth retardation is associated with increased risk of febrile seizures in the first 2 years of life. Adverse environmental and genetic factors during pregnancy may be important in the development of febrile seizures.