Amnioreduction in emergency cerclage with prolapsed membranes: Comparison of two methods for reducing the membranes

To evaluate the effectiveness of amnioreduction in pregnancies requiring em ergency cerclage placement, we performed a retrospective case-control study of all consecutive pregnant women with cervical dilation and effacement wi th prolapse of the fetal membranes in vagina between 16 and 26 weeks' gesta tion, who required placement of a McDonald emergency cerclage during the pe riod January 1991-December 1997. Duration of pregnancy prolongation, rate o f delivery before 32 weeks, and duration of neonatal hospital stay were com pared between women in whom amniochorionic membranes were reduced at the ti me of cerclage placement using only intracervical Foley balloon catheter (c ontrols; n = 7) and those who in addition underwent amnioreduction to facil itate cerclage placement (n=9). Statistical analysis utilized Fisher's exac t test and Wilcoxon rank sum test. A p value <0.05 was considered significa nt. There were no procedure-related ruptures of membranes. Gestational age at cerclage and rate of positive cervico-vaginal cultures were not differen t between the two groups. Gestation was prolonged for a median of 100 days (range 4 to 144 days) in the amnioreduction group and 10 days (2 to 133) am ong controls (p = 0.3). The rate of delivery before 32 weeks was significan tly lower (1/7 vs. 6/8, p 0.03) and the duration of neonatal hospital admis sion significantly shorter (median 3 vs. 37 days, p=0.001) in the amnioredu ction group than among controls. The amount of amniotic fluid withdrawn ran ged from 220 to 340 mt. These findings suggest that amnioreduction at the t ime of emergency cerclage placement is associated with a lower rate of extr eme prematurity and related neonatal morbidity.