Clinical

Prophylaxis cuts jaundice risk, doesn't affect breastfeeding

Last Updated: 2005-08-03 13:45:10 -0400 (Reuters Health)

By Anne Harding

NEW YORK (Reuters Health) - Giving breast-fed infants a few ounces of a beta-glucuronidase inhibitor daily for the first week of life reduces their risk of developing jaundice, according to a new report in the August issue of Pediatrics.

The findings suggest it could be possible for infants to reap breastfeeding's benefits without the accompanying higher risk of hyperbilirubinemia.

"It was very well tolerated by the babies and the parents," Dr. Glenn R. Gourley of Oregon Health and Science University in Portland, the study's lead author, told Reuters Health. "In general, the study was seen as a very positive thing, and it didn't interfere with breastfeeding in any way."

Previous research has shown that infant formula is protective against jaundice, particularly formulas that contain beta-glucuronidase inhibitors. Breast milk is rich in this enzyme, which, in utero, helps to clear bilirubin from the fetal circulation via the placenta. But after birth, the enzyme promotes jaundice by slowing its clearance from the body.

Dr. Gourley's team determined whether giving breast-fed infants small amounts of beta-glucuronidase inhibitors would reduce their risk of jaundice. Sixty-four breastfed infants were randomized to four groups: controls, who received no additional supplementation; or three groups given six 5-mL doses of L-aspartic acid, enzymatically hydrolyzed casein (EHC) or whey/casein daily. Whey/casein does not contain beta-glucuronidase inhibitors.

At day 4 after birth, all the infants given prophylaxis had lower transcutaneous bilirubin levels than the control infants. Bilirubin levels in babies given L-aspartic acid were a mean 75.8% lower, while they were 69.6% and 69.2% lower for those given EHC or whey/casein, respectively. Infants given L-aspartic acid also excreted significantly more bile in the stool.

Because whey/casein does not contain beta-glucuronidase, it must prevent jaundice by some other mechanism, Dr. Gourley noted. "We don't really have an explanation for that."

There was no difference among the four groups in terms of weight gain, amount of milk per feeding, age at first supplementation or duration of breastfeeding.

When the researchers looked specifically at 17 infants with bilirubin levels above the low-risk zone within 48 hours of birth, they found those given EHC or L-aspartic acid showed a faster decline to the low-risk zone than those who were not given glucuronidase inhibitors. "To be able to see the finding on such a small number is encouraging that it would be worth doing further studies," Dr. Gourley said.

The next step, he added, will be to investigate whether certain prophylactic combinations could be more effective and whether it might be possible to give prophylaxis for a shorter period of time. "The less you'd have to do it, the nicer it would be for parents," he said.

Pediatrics 2005;116:385-391.