Abstract

Objective: The purpose was to determine the effect of vaginal pessaries in patients at risk for spontaneous preterm birth (SPB).

Study Design: Transvaginal sonography (TVS) was longitudinally performed to measure cervical length (CL) in 258 singleton at risk for SPB and 282 twin pregnancies. Pairs with or without treatment were matched for gestational age and the CL at examination.

Results: In 4 singleton and 7 twin pregnancies the CL was < 15 mm before 24 weeks, the mean interval between pessary insertion and delivery was 13+2 and 12+5 weeks respectively. For the matched control analysis, 12 pairs with singleton and 23 pairs with twin pregnancies were compared. For singleton pregnancies, the mean interval between TVS and delivery was 99 (70–134) days in the treatment and 67 (2–130) days in the control group (p = 0.0184), the mean gestational age at delivery was 38 (36+6–41) and 33+4 (26–38) weeks respectively (p = 0.02). For twin pregnancies, the interval was 85 (43–129) days in the treatment and 67 (21–100) days in the control group (p = 0.001), gestational age at delivery was 35+6 (33–37+4) and 33+2 (24+4–37+2) respectively (p = 0.02). Within singleton pregnancies with pessary, there was no SPB < 36 weeks compared to 6/12 cases in the control group (p < 0.001). Within twin pregnancies, the rates were 8/23 cases with SPB < 36 weeks but none < 32 weeks, compared to 12/23 cases with SPB < 36 weeks and 7/23 cases < 32 weeks in the control group (p < 0.001).

Conclusions: Insertion of a vaginal pessary may be a cost-effective preventive treatment in patients at risk for SPB. Prospective controlled trials are needed.