Study: Azithromycin use in late pregnancy may pose less risk of neurologic issues in babies than other antibiotics

New research indicates administration of the antibiotic azithromycin late in pregnancy may be tied to a lower risk of neurodevelopmental disorders (NDDs) than other antibiotics used for bacterial infections during pregnancy, researchers reported this week in JAMA Network Open.

An estimated 37% of US women are exposed to antibiotics during pregnancy for bacterial infections, including respiratory and sexually transmitted infections, and roughly 3% use azithromycin, which is also used in expectant mothers to help prevent surgical-site infection after cesarean and vaginal delivery. But the effects of azithromycin use on neurodevelopmental outcomes like autism in children remains undetermined, and studies on the topic have reported conflicting findings, according to a team led by researchers with the University of Rhode Island College of Pharmacy.

To evaluate the risk of NDD's in children exposed to azithromycin during pregnancy, the researchers examined data from an administrative health claims database on a cohort of mother-infant pairs who filled at least one antibiotic prescription or were unexposed to antibiotics during pregnancy from January 2012 through December 2023. The primary outcome was the incidence of NDDs, including attention-deficit/hyperactivity disorder, autism spectrum disorder, speech and language disorder (SLD), developmental coordination disorder, and behavioral disorders.

Significantly lower risk than with other antibiotics

Among the 15,527 mother-infant dyads, 742 (4.8%) were exposed to azithromycin and 3,079 (19.8%) to other antibiotics, while 11,706 (75.4%) were not exposed any antibiotics during pregnancy. 

After a mean follow-up of five-and-a half years, the researchers found no difference in the risk of any NDDs in children exposed to azithromycin versus other antibiotics during the entire or early pregnancy periods, or compared with those unexposed to antibiotics. But in late pregnancy (from 20 weeks of gestation to delivery), they found a significantly lower risk of composite NDDS (adjusted hazard ratio [AHR], 0.69) and SLD (AHR, 0.59) in azithromycin-exposed children compared with those exposed to other antibiotics.

The study authors caution, however, that azithromycin prescribing during pregnancy "should remain guided by clinical necessity and existing safety recommendations."

"Additional studies using larger and more diverse populations are warranted to confirm these results," they concluded.

CWD digest: Wyoming’s National Elk Refuge reports first case

An adult cow elk has tested positive for chronic wasting disease (CWD) in Wyoming Elk Hunt Area 77 in the National Elk Refuge, marking the refuge’s first detection, the Wyoming Game and Fish Department and the US Fish and Wildlife Service announced this week.

The National Elk Refuge is located in the western part of the state between the Teton Mountain Range and the Gros Ventre Wilderness in Jackson Hole. The most recent CWD detection in this herd (Jackson Elk Herd) was in Grand Teton National Park in 2020. 

“Moving forward, National Elk Refuge staff will increase monitoring and surveillance of elk and bison herds for CWD, re-evaluate some existing programs and implement additional bio-security protocols to keep people and wildlife safe,” the release said. “Any changes will be shared with the public.”

Multiple modes of transmission

CWD is a fatal neurodegenerative disease that affects cervids such as deer, elk, and moose. Caused by infectious misfolded proteins called prions, CWD spreads from cervid to cervid through contact with infected saliva, urine, and feces; through environmental contamination; and from infected does to offspring during pregnancy.

Moving forward, National Elk Refuge staff will increase monitoring and surveillance of elk and bison herds for CWD, re-evaluate some existing programs and implement additional bio-security protocols to keep people and wildlife safe.

The disease is not known to affect people, but health agencies recommend against consuming the meat of a sick or infected cervid and advise having cervids harvested in CWD-endemic areas tested before eating the meat.