Progesterone for Preventing Preterm Labor and Delivery
During pregnancy, the
placenta makes high levels of the hormone
progesterone, which helps support the pregnancy. A
drop in progesterone levels is thought to be one of many factors that help
start labor contractions.1
shown that progesterone treatment in the second
trimester helps lower the risk of preterm birth. This
means that although some women still delivered prematurely, progesterone
treatment helped more high-risk women carry their pregnancies longer than a
placebo treatment did.2, 3 (In this case, "high-risk" meant
that a woman had had at least one preterm birth in the past.)
high-risk women, progesterone has been shown to reduce preterm birth.4
There is no evidence that progesterone
treatment prevents early
Progesterone is a new
treatment. And the type of progesterone used in this research, 17
alpha-hydroxyprogesterone caproate, is not available in all areas of the
The American College of Obstetricians and Gynecologists
(ACOG) advises doctors to consider weekly progesterone injections only for
women who are at high risk for preterm labor. This is based on studies of women
who have had a previous spontaneous preterm birth (before 37 weeks).5 More research is needed before other high-risk women, such as
those who already have signs of preterm labor or women who are pregnant with
twins or more, can be considered for progesterone treatment.
Da Fonseca EB, et al. (2003). Prophylactic
administration of progesterone by vaginal suppository to reduce the incidence
of spontaneous preterm birth in women at increased risk: A randomized
placebo-controlled double-blind study. American Journal of Obstetrics and Gynecology, 188(2): 419-424.
Meis PJ, et al. (2003). Prevention of recurrent
preterm delivery by 17 alpha-hydroxyprogesterone caproate. New England Journal of Medicine, 348(24): 2379-2385.
Mackenzie R, et al. (2006). Progesterone for the
prevention of preterm birth among women at increased risk: A systematic review
and meta-analysis of randomized controlled trials. American Journal of Obstetrics and Gynecology, 194: 1234-1242.
Haas DM (2010). Preterm birth, search date June 2009.
Online version of BMJ Clinical Evidence:
American College of Obstetricians and Gynecologists
(2008). Use of progesterone to reduce preterm birth. ACOG Committee Opinion No.
419. Obstetrics and Gynecology, 112:
Primary Medical Reviewer
Sarah Marshall, MD - Family Medicine
Specialist Medical Reviewer
William Gilbert, MD - Maternal and Fetal Medicine
January 10, 2011
WebMD Medical Reference from Healthwise
January 10, 2011
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