PREMATURE RUPTURE OF THE MEMBRANES BETWEEN 20 AND 25 WEEKS GESTATION - ROLE OF AMNIOTIC-FLUID VOLUME IN PERINATAL OUTCOME

OBJECTIVE: Our purpose was to prospectively study the relationship bet ween amniotic fluid volume and perinatal outcome in pregnancies compli cated by premature rupture of the membranes before fetal viability. ST UDY DESIGN: The study population consisted of 178 singleton pregnancie s with premature rupture of membranes between 20 and 25 weeks' gestati on who were managed expectantly. Serial amniotic fluid volume measurem ents were made and their relationship to the neonatal survival rate, i ncidence of chorioamnionitis, and other perinatal outcomes was determi ned. RESULTS: Seventy-four patients were delivered before 25 weeks of gestation and only five infants (6.7%) survived. In contrast, 104 pati ents were delivered between 26 and 34 weeks, and 93 infants (89.4%) su rvived (p < 0.001). There were 107 pregnancies with adequate amniotic fluid volume after premature rupture of membranes on admission. Of the se 16 patients were delivered before 25 weeks of gestation, and the re maining 91 patients were able to carry their pregnancies beyond 25 wee ks of gestation. This was significantly different from 71 patients who demonstrated inadequate amniotic fluid volume on admission to the hos pital, of whom 58 were delivered before 25 weeks and only 13 continued the pregnancy beyond 25 weeks (p < 0.05). At gestations between 26 an d 34 weeks chorioamnionitis occurred in 22 of 91 (24.1%) patients with adequate amniotic fluid volume versus nine of 13 patients (69.2%) wit h inadequate amniotic fluid volume (p < 0.001). The incidence of perin atal death for pregnancies between 26 and 34 weeks with adequate versu s inadequate amniotic fluid volume was 2.1% and 69.2%, respectively (p < 0.001). Overall survival rate and incidence of chorioamnionitis wer e 55% and 26.4%, respectively. CONCLUSIONS: Delivery of pregnancies be tween 20 and 25 weeks of gestation with premature rupture of membranes carries very high risk of neonatal mortality. The results of this stu dy suggest that women with adequate amniotic fluid volume have a bette r chance to continue their pregnancy beyond 25 weeks of gestation and have a higher neonatal survival rate than those with inadequate amniot ic fluid volume. The incidence of perinatal death and chorioamnionitis in patients who carry a pregnancy beyond 25 weeks is correlated with inadequate amniotic fluid volume.