Preterm birth can be dangerous for newborns and their mothers, and not all preterm births are alike – the earlier they are, the greater the risk. This is why medications and treatment designed to avoid preterm birth aim to prolong pregnancy until as close to full term as possible, whether that means adding three days to the length of a pregnancy, or three weeks.
Who might progesterone be a good fit for?
Studies show that vaginal progesterone treatments may help reduce the risk of preterm birth for those with a short cervix.
What if you have a history of preterm birth?
Those who have had spontaneous preterm deliveries of single babies in the past are especially at risk for preterm delivery. Some research suggested that progesterone treatment was helpful for those with a history of prior preterm birth, and that getting weekly progesterone injections would lower the risk of preterm labor. However, the PROLONG study published in 2020 found that weekly progesterone injections did not have a significant benefit for those with a history of preterm birth. Therefore weekly progesterone injections are no longer recommended as a medication to prevent preterm birth. Vaginal progesterone is recommended for those with a short cervix as defined by less than 2.5cm, in people with and without a history of preterm birth. Vaginal progesterone is not recommended for people with a history of preterm birth as a solo risk factor.
How does it work?
Progesterone works by relaxing the uterus thus preventing the contractions that kickstart labor and helps maintain a stable cervical length. This means that even in cases where progesterone treatments don’t prevent preterm labor, they may delay labor significantly, giving babies longer to develop in the womb. Babies who are considered to be “late preterm” – babies born between 34 and 36 weeks gestation – have a lower risk of health complications, and the closer to term a pregnancy gets, there is even less risk of complications for the baby
Progesterone isn’t an effective treatment for those carrying twins or multiples, and may not be right for those who have personal histories of certain health conditions.
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Sources
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- S.S. Hassan. “Vaginal progesterone reduces the rate of preterm birth in women with sonographical short cervix: a multicenter, randomized, double-blind, placebo-controlled trial.” Ultrasound in Obstetrics and Gynecology. 38(1): 18-31. July 2011. Retrieved December 20 2017. https://www.ncbi.nlm.nih.gov/pubmed/21472815.
- Paul J. Meis, et al. “Prevention of Recurrent Preterm Delivery by 17 Alpha Hydroxyprogesterone Caproate.” New England Journal of Medicine. 2003; 348:2379-2385. June 12 2003. Retrieved December 20 2017. http://www.nejm.org/doi/full/10.1056/NEJMoa035140.
- M.S. To, J. Miletin, J. Semberova, S. Daly. “Is routine tranvaginal cervical length measurement cost-effective in a population where the risk of spontaneous preterm birth is low?” Acta Obstetrica Gynecologica Scandinavica. 95(12): December 2016. Retrieved December 19 2017. https://www.ncbi.nlm.nih.gov/pubmed/27623283.
- “Preterm birth fact sheet.” World Health Organization. World Health Organization, November 2017. Retrieved December 20 2017. http://www.who.int/mediacentre/factsheets/fs363/en/.
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- Cerner Multum. “Progesterone vaginal.” University of Michigan. Regents of the University of Michigan, March 13 2015. Retrieved December 19 2017. http://www.uofmhealth.org/health-library/d00550t1.
