''We compared the breastfed babies to non-breastfed babies and basically found no difference at all in IQ at age 3," says researcher Kimford Meador, MD, professor of neurology at Emory University School of Medicine, Atlanta.
The average IQ found for the breastfed babies was 99, Meador tells WebMD, while the average for non-breastfed babies was 98. "The average for the general population is 100," he says.
The study is published in the journal Neurology.
For instance, valproic acid, an epilepsy drug that is often avoided in reproductive-age women if possible, has been shown to contribute to major birth defects if used in the first trimester. In his previous research, Meador has found that at age 3, children who were exposed in utero to valproic acid had an IQ that was 9 points lower than children exposed to another epilepsy drug, lamotrigine.
The new study is an ongoing analysis of the Neurodevelopmental Effects of Antiepileptic Drugs (NEAD) Study, conducted from 1999 to 2004.
For this study, Meador's team followed 194 pregnant women who were taking a single epilepsy drug. At age 3, they tested the IQ of the women's 199 babies (including twins).
Of these, 82 breastfed for a median of six months (half did so longer, half less) while the other 112 did not breastfeed.
The women took one of four different anti-epilepsy drugs, including:
- carbamazepine (Carbatrol, Epitol, Equetro, Tegretol)
- lamotrigine (Lamictal)
- phenytoin (Dilantin)
- valproate [valproic acid derivative] (Epilim, Depakene, Depacon, Depakote, Stavzor)
No substantial differences in IQ tests at age 3 were found when the researchers compared breastfed to non-breastfed children, and no substantial differences were found between the four different drugs.
''Even kids who got valproate and breastfed had no difference," Meador says. This might be due to the lower dose of the drugs in breast milk that is transmitted to the baby compared to the amount the baby gets during in utero exposure, he says.
Of the breastfeeding study results, Meador says: ''It's good news. It's the first study that actually looked at the effect of breastfeeding when women are taking anti-epilepsy drugs and we do not see any evidence or sign there are adverse effects on the child's IQ at 3 years of age."
Like other experts, he recommends women of childbearing age avoid valproic acid if possible. But, he says, there is a population of women with epilepsy whose disease is best controlled by valproic acid.
Meador reports receiving research grants from GlaxoSmithKline and Eisai Pharmaceuticals, which make epilepsy drugs, and other companies.
The new study results should provide reassurance for women with epilepsy who wish to breastfeed, says Autumn Klein, MD, PhD, director of the Program in Women's Neurology, Brigham and Women's Hospital, and instructor in neurology, Harvard Medical School, Boston. She wrote an editorial to accompany the study.
''After delivery, the child is getting a lot less [drug exposure] than they got in utero," she says.
Women typically ask her about which drug might be better during breastfeeding. There isn't yet enough data to comment on that, she says, as the numbers of women in this study taking each drug were too low to tease out a difference.
She does agree that women should avoid valproate if possible.
Klein is the recipient of research support from the Epilepsy Foundation of America.