Progestogens, cervical cerclage, and cervical pessary for preventing preterm birth in asymptomatic singleton pregnancies with a sonographic short cervix and no previous history of spontaneous preterm birth: systematic review and bayesian network meta-analysis.
Hanglin Wu, Liming Yu, Jindi Zhang et al.
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In 30 seconds
This systematic review and Bayesian network meta-analysis compared interventions to prevent preterm birth in asymptomatic women with singleton pregnancies, a sonographic short cervix, and no previous spontaneous preterm birth. It included 26 randomised controlled trials involving 8561 women; 6004 contributed to the network meta-analysis. Vaginal progesterone was supported by high-certainty direct evidence for reducing birth before 34 weeks (risk ratio 0.56, 95% confidence interval 0.44 to 0.72) and ranked highly in network analyses. It was also associated with fewer maternal adverse events than combination treatments.
Key findings
- Vaginal progesterone reduced preterm birth before 34 weeks in direct comparisons (risk ratio 0.56, 95% confidence interval 0.44 to 0.72), with high-certainty evidence.
- For birth before 34 weeks, vaginal progesterone had a 96.4% probability of risk ratio <1.00; pessary plus vaginal progesterone had a 99.1% probability.
- For birth before 37 weeks, vaginal progesterone had a 92.0% probability of risk ratio <1.00.
- Maternal adverse events were less frequent with vaginal progesterone monotherapy than with combination treatments (risk ratio 0.56, 95% CI 0.42 to 0.76).
Why it matters
The findings help distinguish interventions with stronger direct evidence from those whose favourable rankings rely on less certain comparisons. Vaginal progesterone combined evidence of efficacy with a lower risk of maternal adverse events than combination treatments, while most secondary outcomes had generally low-certainty evidence and substantial variability between studies.
What to keep in mind
Evidence certainty was generally low for most secondary outcomes, with moderate to high between-study variability. Network rankings do not replace the high-certainty direct evidence available for vaginal progesterone.