Ampicillin and Gentamicin Combo bests ampicillin for managing PROM at term: Study

Researchers found that using ampicillin and gentamicin for prophylaxis in term premature rupture of membranes, compared to ampicillin alone, leads to lower rates of clinical chorioamnionitis, maternal postpartum complications, and neonatal adverse outcomes. The finding, published in the American Journal of Obstetrics and Gynecology, suggests the need to reassess the current antimicrobial prophylactic regimen for better maternal and neonatal outcomes.

When the water bag breaks before labor begins, a condition known as PROM, increases the risk of infections in both the mother and baby. Doctors often prescribe ampicillin for patients whose group B Streptococcus (GBS) status is unknown, especially if PROM lasts more than 18 hours. The researchers, however, note that some bacteria, like ampicillin-resistant Enterobacteriaceae, can also cause infections in mothers and newborns. Current guidelines for antibiotic use during labor mainly focus on preventing GBS infections but do not fully address the risk posed by these resistant bacteria.

Against the above background, Maya Frank Wolf, Azrieli Faculty of Medicine, Bar Ilan University, Safed, Israel, and colleagues aimed to evaluate the risk of infections in mothers and newborns when treated with two different antibiotic regimens: ampicillin plus gentamicin versus ampicillin alone.

For this purpose, the researchers conducted a randomized-controlled trial at a university hospital between November 2022 and March 2024. They included women with term pregnancies (>37 weeks), unknown GBS status, and PROM without active labor, while excluding those with allergies, contraindications for vaginal delivery, or prior antibiotic use. Participants were randomly assigned to receive either ampicillin plus gentamicin (n=102) or ampicillin alone (n=102).

The primary outcome was clinical chorioamnionitis, while secondary outcomes included maternal infections and neonatal complications: microbiologic analysis and statistical methods assessed risk factors and treatment effectiveness, including multivariate regression.

The key findings of the study were as follows:

• Fewer cases of clinical chorioamnionitis were seen with ampicillin and gentamicin (1.0% vs. 7.8%).
• Lower incidence of fever during labor (8.0% vs. 18.0%).
• Reduced overall risk of infections around childbirth (1.0% vs. 9.8%).
• To prevent one case of clinical chorioamnionitis, 15 patients need treatment with ampicillin and gentamicin.
• Fewer postpartum complications in mothers (0% vs. 5.9%).
• Lower neonatal complications (10.8% vs. 21.6%).
• Fewer sepsis evaluations in newborns (7.8% vs. 17.6%).
• Shorter NICU stays (3.0 vs. 3.5 days).
• Lower presence of resistant bacteria in chorioamniotic samples (20% vs. 51%).Bottom of Form

In term PROM, using ampicillin and gentamicin together significantly reduces the risk of clinical chorioamnionitis, maternal postpartum complications, and neonatal adverse outcomes compared to ampicillin alone.

"These findings highlight the need to reassess the current antibiotic regimen for better infection prevention in mothers and newborns," the authors concluded.

Reference:

Abu Shqara, R., Glikman, D., Goldinfeld, G., Braude, O., Assy, S., Hassan, D., Sgayer, I., Ganem, N., Shasha-Lavsky, H., Yefet, E., Matanis, M., Lowenstein, L., & Frank Wolf, M. (2025). Ampicillin and gentamicin prophylaxis is superior to ampicillin alone in patients with prelabor rupture of membranes at term: The results of a randomized clinical trial. American Journal of Obstetrics and Gynecology. https://doi.org/10.1016/j.ajog.2025.03.011