Prozac Used by Breastfeeding Mothers May Affect Baby's Weight

From the WebMD Archives

Dec. 3, 1999 (Atlanta) -- Many women continue to use the antidepressant Prozac (fluoxetine) while they breastfeed, despite the concerns expressed by the American Academy of Pediatrics, the FDA, and the manufacturer of the drug. One likely reason: There's been little research to back up those concerns, until now.

According to a study in the November issue of Pediatrics, the use of Prozac by women while they are breastfeeding does not lead to any unusual behavior in their babies. However, the drug is linked with reduced growth in these infants.

"There may be an effect that you need to watch for in babies who are exposed to [Prozac] during breastfeeding," says lead author Philip Anderson, PharmD, with the department of pharmacy at the University of California, San Diego Medical Center. "To me, [the findings] ... make it a less desirable medication to use in mothers who are depressed and want to breastfeed."

In the study, 64 women who took Prozac during pregnancy between 1989 and 1997 were interviewed about frequency of any side effects. All of the women breastfed their babies, but only 26 continued to take Prozac while breastfeeding. Pediatric records were used to measure the babies' weight gain.

The infants of the mothers who continued to take Prozac were significantly lower in weight than infants who were breastfed by mothers not on the drug. Between two weeks and six months of age the average deficit in weight was just under 14 ounces. "[That's] not considered to be a real serious risk to the baby's health in terms of decreased weight gain," says Anderson. "But we are dealing with averages. And there are some babies at the far end of spectrum where the effect could be great enough to be of concern."

"There are other papers that have found kind of a pattern of side effects that seems consistent among a bunch of different case reports -- fussiness and colic, and agitation," says Anderson. "Those are hard to detect, since babies are fussy."

The weight loss experienced by the infants may be explained in several ways, according to the researchers. First, the drug may directly inhibit weight gain in infants who receive it through breast milk; weight loss is a commonly noted side effect of Prozac in adults.


Second, the nursing mothers may have breastfed less often or engaged in other behaviors that affected the infants' weight gain. Third, the lower weight could be due to the mother's use of the drug while she was pregnant. "I think it's somewhat of a preliminary study. ... It's not definitive," Anderson tells WebMD.

The age of the infant and the mother's medical history should factor into any decisions about prescribing Prozac, according to Anderson.

"If she is just starting this medication for the first time, I would suggest using a different drug and not using Prozac to start with," he says. "If she has been taking it through pregnancy and now she is going to start nursing, I think the benefits of nursing still outweigh the potential risks of Prozac. But the physician needs to watch very carefully the weight gain and the behavior of the infant and make sure there aren't colicky symptoms and the baby is gaining weight adequately. If the baby is 1 year old, and the mother is nursing three or four times a day and feeding the baby a lot of food, I don't think it makes any difference which [medication] they choose. ... All in all, use something else first whenever possible."

"There are better alternatives," says Anderson. He says that information is available on Pamelor (nortriptyline ) and Zoloft (sertraline). "Those medications are not detectable in the babies' serum even when the babies are nursing. Some recent data looks like Paxil [paroxitene] is a pretty good choice, too."

Vital Information:

  • Continuing to take Prozac while breastfeeding is not associated with any unusual behavior in children, but it is linked to reduced growth.
  • The drug may directly inhibit weight gain in these infants, or it could be a result of a behavior by the mothers.
  • There are alternative antidepressant medications that nursing mothers could take that do not seem to affect babies.
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