Body dimensions of infants exposed to antiepileptic drugs in utero: Observations spanning 25 years

Purpose: To investigate the influence of maternal antiepileptic drug (AED) treatment on pregnancy duration, birth weight, body length, head circumfere nce, and intrauterine growth in infants exposed in utero to antiepileptic d rugs in Sweden between 1973-1997, with 963 singleton infants. Methods: Data collected from (a) 1973-1981 (record linkage between a hospit al discharge register and a medical birth register); (b) 1984-1995 (prospec tively collected information in one defined catchment area with two deliver y hospitals); and (c) 1995-1997 (medical birth register data). Observed num bers of infants below a defined size for body measurements compared with ex pected numbers calculated from all births in Sweden after stratification fo r year of birth, maternal age, parity, and education or smoking habits in e arly pregnancy. Standard deviation scores estimated with same stratificatio n procedures. Results: Fraction of monotherapy exposures increased from similar to 40% to similar to 90% from 1973 to 1997. Significantly increased numbers of infan ts with small body measurements found in exposed group. Negative influence on body dimensions decreased over time. More marked effects found in infant s exposed to polytherapy. In monotherapy, only infants exposed to carbamaze pine consistently showed reduction in body dimensions. Significant effect o n gestational age in girls and on number of small for gestational age (<2 S D) in boys. Conclusions: Polytherapy with antiepileptic drugs and negative influence on body dimensions decreased. In monotherapy, only carbamazepine has a negati ve influence on body dimensions in this study.