Use of ampicillin and corticosteroids in premature rupture of membranes: a randomized study.

A randomized study was conducted to investigate the effects of antenatal corticosteroids and ampicillin in the management of preterm pregnancies under 34 weeks complicated by premature rupture of membranes. Patients with documented lecithin/sphingomyelin (L/S) ratios of less than 2.0 and a singleton gestation were eligible to participate in the study. One hundred sixty-five patients qualified and were randomized, using sealed envelopes, to four study groups. All patients were followed expectantly. Group I (41 patients) received neither ampicillin nor corticosteroids. Group II (43 patients) received 24 mg of antenatal betamethasone. Group III (37 patients) received 2 g of intravenous ampicillin every 6 hours, with discontinuation of antibiotic therapy if cultures were negative for pathogenic bacteria. Group IV (44 patients) received both corticosteroids and ampicillin as described for groups II and III, respectively. Compared with patients not receiving corticosteroids, those administered antenatal corticosteroids experienced a reduction in the incidences of respiratory distress syndrome (53 versus 26%), bronchopulmonary dysplasia (23 versus 9%), severe grades of intracranial hemorrhage (15 versus 3%), and patent ductus arteriosus (18 versus 6%), with no difference in the incidence of maternal or neonatal infection. Compared with patients not receiving antenatal antibiotics, the group of patients treated with ampicillin on admission had a lower incidence of clinical chorioamnionitis (4 versus 26%) and neonatal sepsis (5 versus 10%). This reduction in infectious morbidity by antenatal ampicillin was restricted to those patients (28.4% of the study population) colonized with group B streptococci.(ABSTRACT TRUNCATED AT 250 WORDS)