Because breastfeeding has many psychological and medical benefits for both the mother and her child, many women would like to breastfeed. However, all medications taken by the mother are secreted into the breast milk. While various studies have addressed the short-term safety of antiepileptic drugs (AEDs) in nursing infants, none have systematically assessed the long-term effects of exposure to these drugs on cognitive development.

Several years ago, we reported on data from the Neurodevelopmental Effects of Antiepileptic Drugs (NEAD) Study, an ongoing prospective multicenter observational investigation designed to examine the long-term effects of in utero AED exposure on cognition. Pregnant women with epilepsy treated with a single AED (carbamazepine, lamotrigine, phenytoin, or valproate) were recruited during pregnancy and were followed prospectively. In the first report, the authors reported on the cognitive outcomes of 199 children at 3 years of age. After adjusting for maternal IQ, mean adjusted IQ scores across all AEDs were 99 (range 96–103) for breastfed children and 98 (95–101) for non-breastfed children.

In the most recent report from this group, Meador and colleagues reported on the outcomes of 181 children at 6 years of age. 42.9% of the children were breastfed (mean duration of 7.2 months; range, 3-24 months). Breastfeeding rates and duration did not differ across drug groups. The child’s IQ assessed at 6 years of age was affected by the following factors:

  • Maternal IQ: Higher child IQ was observed with higher maternal IQ.
  • Drug group: Prenatal exposure to valproate was associated with lower IQ.
  • Drug dose: Lower IQ was observed in infants exposed to higher dosages of AED.
  • Use of folate at the time of conception: IQ was higher by 6 points in children whose mothers were taking folate supplements.
  • Breastfeeding: Overall, adjusted IQ was higher by 4 points for children who were breastfed compared to those who were not.

These findings were similar to those observed in the children assessed at 3 years of age. Fetal valproate exposure was associated with lower IQ in a dose-dependent manner. Given the various risks associated with valproate exposure, the American Academy of Neurology recommends that valproate should be avoided, if possible, during pregnancy to minimize the risk of major congenital malformations and cognitive impairment.

If we were to assume that AEDs secreted into the breast milk conferred risk with regard to cognitive development, we would expect that IQs would be lower in children who were breastfed as compared to those who were not. Instead we see that, the IQs among breastfed were about 4 points higher among children who were breastfed. This is not a huge difference, but it does show us that exposure to AEDs in the breast milk does not confer additional risk with respect to cognitive development.

While these data are reassuring, there are several limitations to this study. First, the numbers of subjects included were not large enough to detect differences in outcomes among the different AEDs. In addition, there are no control groups for comparison, such as women not taking AEDs or women taking AEDs only during breastfeeding and not during pregnancy. In addition, IQ may be a relatively crude instrument for detecting subtle changes in cognitive development. Despite these limitations, this study provides important information to women taking AEDs who are considering breastfeeding.

Ruta Nonacs, MD PhD

Meador KJ, Baker GA, Browning N, Cohen MJ, et al. Breastfeeding in Children of Women Taking Antiepileptic Drugs: Cognitive Outcomes at Age 6 Years. JAMA Pediatr. 2014 Jun 16.

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