Original Paper
Vaginal progesterone reduces the rate of preterm birth in women with a sonographic short cervix: a multicenter, randomized, double-blind, placebo-controlled trial
Article first published online: 15 JUN 2011
DOI: 10.1002/uog.9017
Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Additional Information
How to Cite
Hassan, S. S., Romero, R., Vidyadhari, D., Fusey, S., Baxter, J. K., Khandelwal, M., Vijayaraghavan, J., Trivedi, Y., Soma-Pillay, P., Sambarey, P., Dayal, A., Potapov, V., O'Brien, J., Astakhov, V., Yuzko, O., Kinzler, W., Dattel, B., Sehdev, H., Mazheika, L., Manchulenko, D., Gervasi, M. T., Sullivan, L., Conde-Agudelo, A., Phillips, J. A., Creasy, G. W. and for the PREGNANT Trial (2011), Vaginal progesterone reduces the rate of preterm birth in women with a sonographic short cervix: a multicenter, randomized, double-blind, placebo-controlled trial. Ultrasound Obstet Gynecol, 38: 18–31. doi: 10.1002/uog.9017
Publication History
- Issue published online: 28 JUN 2011
- Article first published online: 15 JUN 2011
- Accepted manuscript online: 6 APR 2011 08:57AM EST
- Manuscript Accepted: 5 APR 2011
Keywords:
- pregnancy;
- preterm delivery;
- preterm labor;
- progestins;
- progestogens;
- respiratory distress syndrome;
- transvaginal ultrasound;
- uterine cervix;
- vaginal administration
Abstract
Objectives
Women with a sonographic short cervix in the mid-trimester are at increased risk for preterm delivery. This study was undertaken to determine the efficacy and safety of using micronized vaginal progesterone gel to reduce the risk of preterm birth and associated neonatal complications in women with a sonographic short cervix.
Methods
This was a multicenter, randomized, double-blind, placebo-controlled trial that enrolled asymptomatic women with a singleton pregnancy and a sonographic short cervix (10–20 mm) at 19 + 0 to 23 + 6 weeks of gestation. Women were allocated randomly to receive vaginal progesterone gel or placebo daily starting from 20 to 23 + 6 weeks until 36 + 6 weeks, rupture of membranes or delivery, whichever occurred first. Randomization sequence was stratified by center and history of a previous preterm birth. The primary endpoint was preterm birth before 33 weeks of gestation. Analysis was by intention to treat.
Results
Of 465 women randomized, seven were lost to follow-up and 458 (vaginal progesterone gel, n = 235; placebo, n = 223) were included in the analysis. Women allocated to receive vaginal progesterone had a lower rate of preterm birth before 33 weeks than did those allocated to placebo (8.9% (n = 21) vs 16.1% (n = 36); relative risk (RR), 0.55; 95% CI, 0.33–0.92; P = 0.02). The effect remained significant after adjustment for covariables (adjusted RR, 0.52; 95% CI, 0.31–0.91; P = 0.02). Vaginal progesterone was also associated with a significant reduction in the rate of preterm birth before 28 weeks (5.1% vs 10.3%; RR, 0.50; 95% CI, 0.25–0.97; P = 0.04) and 35 weeks (14.5% vs 23.3%; RR, 0.62; 95% CI, 0.42–0.92; P = 0.02), respiratory distress syndrome (3.0% vs 7.6%; RR, 0.39; 95% CI, 0.17–0.92; P = 0.03), any neonatal morbidity or mortality event (7.7% vs 13.5%; RR, 0.57; 95% CI, 0.33–0.99; P = 0.04) and birth weight < 1500 g (6.4% (15/234) vs 13.6% (30/220); RR, 0.47; 95% CI, 0.26–0.85; P = 0.01). There were no differences in the incidence of treatment-related adverse events between the groups.
Conclusions
The administration of vaginal progesterone gel to women with a sonographic short cervix in the mid-trimester is associated with a 45% reduction in the rate of preterm birth before 33 weeks of gestation and with improved neonatal outcome. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.

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