Pessary placement in the prevention of preterm birth in multiple pregnancies: a propensity score analysis

OBJECTIVE: In asymptomatic women with a multiple pregnancy and short cervix prophylactic use of a cervical pessary might reduce preterm birth. We assessed the possible treatment effects of pessary use in pregnancy duration and for poor perinatal outcome.

STUDY DESIGN: This cohort study was performed between December 2012 and September 2014 in 44 hospitals in the Netherlands. Women with multiple pregnancy had a cervical length measurement between 16 and 22 weeks of gestation. When cervical length was below 38mm, women were offered a cervical pessary. The course of pregnancy, including perinatal outcome in these women was compared to the outcome of women from the placebo group of the AMPHIA trial (ISRCTN40512715) (historical cohort). Propensity-score matching with replacement was used to create comparable baseline characteristics between both populations.

RESULTS: We studied 63 women in the pessary group and 56 women as controls. Propensity-score matching generated 57 women in the intervention group matched to 57 women (31 unique) in the control group. Gestational age at delivery was comparable between both groups (HR 0.96, 95%-CI 0.46-1.46) as well as their delivery rates before 28, 32 and 37 weeks, RR 0.68 (95%-CI 0.21-2.18), RR 0.54 (95%-CI 0.21-1.41), and RR 1.22 (95%-CI 0.47-3.15), respectively. There was no difference in composite perinatal outcome (RR 1.36, 95%-CI 0.53-3.51) and perinatal mortality (RR 0.89, 95%-CI 0.24-3.38) either.

CONCLUSION: In this cohort study with propensity score analysis, pessary use did not prevent preterm birth in asymptomatic women with a multiple pregnancy and short cervix.