New British Study Finds Progesterone Suppositories May Not Be Effective In Preventing Preterm Birth

March of Dimes Urges Continued Use of 17P Injections

Feb 29, 2016, 15:14 ET from March of Dimes

WHITE PLAINS, N.Y., Feb. 29, 2016 /PRNewswire-USNewswire/ -- The largest study of vaginal progesterone to date did not conclusively demonstrate that the treatment was effective in preventing preterm birth before 34 weeks in certain women at high risk for giving birth early, according to findings published last week in The Lancet.

The multicenter trial, called "OPPTIMUM" (dOes Progesterone Prophylaxis To prevent preterm labour IMprove oUtcoMe?) was conducted in the United Kingdom among 1,228 women considered at risk of preterm birth because they had a positive fetal fibronectin (a protein produced by fetal cells) test and a history of spontaneous preterm birth or a shortened cervical length detected by ultrasound. It also found that vaginal progesterone provided no long-term benefit or harm to the health of children at two years of age.

"It's important to note that this was a study of just one form of progesterone and not the type recommended for weekly use among women with a prior spontaneous preterm birth by the American College of Obstetricians and Gynecologists (i.e., weekly injections of 17-hydroxyprogesterone caproate or 17P)," said Charles J. Lockwood, MD, MHCM, Senior Vice President, University of South Florida (USF) Health, Dean, USF Health Morsani College of Medicine, and a member of the March of Dimes Board of Trustees. "Evidence for the effectiveness of injectable 17P to prevent recurrent prematurity remains strong.  It should also be noted that the OPPTIMUM study was not large enough to exclude up to 15 percent reduction in preterm birth from vaginal progesterone in this population. Preterm birth is the number one killer of babies in the United States and the March of Dimes urges the use of all effective measures available to prevent babies from being born too soon."

Dr. Lockwood also noted that a study published by the March of Dimes, the National Institutes for Health, and the Centers for Disease Control and Prevention, using data from 2002, estimated that if all women eligible for 17P injections in the United States received them, nearly 10,000 spontaneous premature births might be prevented each year.

March of Dimes officials said the organization is not changing its position that vaginal progesterone may help reduce the risk for premature birth for women with a short cervix who are pregnant with just one baby.

"Vaginal progesterone prophylaxis for preterm birth (the OPPTIMUM study): a multicentre, randomised, double-blind trial" by Jane Elizabeth Norman and colleagues of the OPPTIMUM study group appeared online in The Lancet, February 23, 2016,

The March of Dimes is the leading nonprofit organization for pregnancy and baby health.  For more than 75 years, moms and babies have benefited from March of Dimes research, education, vaccines, and breakthroughs.  Find out how you can help prevent premature birth and birth defects by joining March for Babies at For the latest resources and information, visit or Find us on Facebook and Twitter.

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SOURCE March of Dimes