Antibiotic therapy in patients with preterm premature rupture of membranes: A prospective, randomized, placebo-controlled study with microbiological assessment of the amniotic cavity and lower genital tract

Abstract

Objective: Preterm premature rupture of membranes (PROM) is responsible for one-third of premature deliveries and is associated with maternal and neonatal morbidity and mortality. Several studies have investigated the role of antibiotic therapy in this group of patients with conflicting results. However, routine microbiological assessment of the lower genital tract and amniotic cavity was not performed in those studies. Our purpose was to test the effect of antibiotics in patients with preterm PROM, according to the presence of microbial invasion of the amniotic cavity (MIAC) and cervicovaginal infection. Study design: Between November 1990 and September 1994, patients with preterm PROM between 24 and 34 weeks, without clinical chorioamnionitis and without labor, were enrolled. Amniocentesis was offered to all patients and the cervix and vagina were sampled for microbiological and cytological studies. Patients were then allocated to receive either clindamycin and gentamicin or placebo for 7 days, and managed expectantly until 35 weeks unless maternal or fetal indications for delivery developed. ·Contingency tables, t-test and nonparametric statistics were used for analysis. Results Eighty-eight women with preterm PROM were randomly allocated to either antibiotic administration (clindamycin + gentamicin) (n = 42) or placebo (n = 46). Patients receiving antibiotics had a longer randomization-to-delivery interval than the placebo group (median 10.5 days, range 0-41 vs. median 4 days, range 0-32, respectively; p < 0.05). This effect was stronger in patients with cervicovaginal infection only than in patients with cervicovaginal infection and MIAC. No differences were observed when cervicovaginal infection and MIAC were absent. Maternal infectious morbidity was lower in patients who received antibiotics than in patients receiving placebo (4.8% (2/42) vs. 28.9% (13/45), respectively, p < 0.01 ). This effect occurred particularly markedly in the group with MIAC (antibiotic group: 9.1% (2/22) vs. placebo group: 45.5% (10/22), p < 0.01). Neonates born to mothers who received antibiotics had a lower rate of respiratory distress syndrome than the placebo group (9.5% (4/42) vs. 30.2% (13/43), respectively, p < 0.05) and admission to the intensive care unit was less frequent (54.8% (23/42) vs. 86.0% (37/43), respectively, p < 0.01 ). Antibiotic therapy did not modify the rate of neonatal infection or mortality. Conclusions Antibiotic administration to patients with preterm PROM prolongs the duration of pregnancy, and reduces the rate of maternal infection-related morbidity, the neonatal intensive care unit admission rate and the frequency of respiratory distress syndrome.