Epidemiology

Maternal sulfonamides not tied to neonatal jaundice

Last Updated: 2013-06-18 13:20:27 -0400 (Reuters Health)

By David Douglas

NEW YORK (Reuters Health) - Maternal use of the short-acting sulfonamide sulfamethizole near term does not appear to increase the risk of neonatal jaundice, Danish researchers say.

While current recommendations advise against sulfamethizole in late pregnancy "due to a theoretical risk of kernicterus and jaundice in the offspring," a nationwide cohort study of nearly a million live births found no such association, lead investigator Dr. Pia Klarskov of Rigshospitalet, Copenhagen told Reuters Health by email.

"The study's conclusion is... that it is safe to use sulfamethizole in late pregnancy," Dr. Klarskov added. "Sulfamethizole is an effective and inexpensive antibiotic and, due to its now proven safety, will be a valuable contribution to treatment of bacterial infections in late pregnancy."

The agent is primarily used to treat urinary tract infections, which occur in up to 20% of pregnancies, Dr. Klarskov and colleagues noted in a paper online June 5th in Obstetrics and Gynecology. Not treating those infections can lead to higher risks for preterm delivery and other adverse outcomes.

The toxicity of sulfonamides administered to neonates is well established, but the risk of neonatal jaundice after in utero exposure to short-acting sulfonamides is not, the authors say.

When they analyzed data on 841,900 births (1995-2007), they saw jaundice within 28 days in 41,498 (4.9%) newborns.

In all, 1,823 (0.2%) of the neonates were exposed to sulfamethizole up to four weeks before birth, and 197 of these (10.8%) developed neonatal jaundice.

Before adjustment, the odds ratio was doubled in this group, but after adjustment for gestational age there was no significant association (odds ratio, 1.03) - even with exposure in the last week before birth.

The researchers suspect that in earlier reports, associations between sulfamethizole and jaundice were really due to preterm birth, which could have been a result of maternal urinary tract infection and not the antibiotic.

The new findings are also in line with an earlier Danish study involving more than 63,000 newborns.

Concerns in the literature about avoiding sulfonamides in late pregnancy are not based on studies with short-acting sulfonamides, the researchers say, adding, "The precautions regarding short-acting sulfonamides seem, therefore, to be theoretical and not scientifically or empirically based."

"It is more likely that maternal urinary tract infection may cause prematurity and thereby increased risk of neonatal jaundice," the research team concludes. "Sulfamethizole is inexpensive and effective, and it might therefore be time to disregard old hypothetical views on sulfonamides."

SOURCE: http://bit.ly/16ESJs8

Obstet Gynecol 2012.