A trial of 17 alpha-hydroxyprogesterone caproate to prevent prematurity in twins.
BACKGROUND
In singleton gestations, 17 alpha-hydroxyprogesterone caproate (17P) has been shown to reduce the rate of recurrent preterm birth. This study was undertaken to evaluate whether 17P would reduce the rate of preterm birth in twin gestations.


METHODS
We performed a randomized, double-blind, placebo-controlled trial in 14 centers. Healthy women with twin gestations were assigned to weekly intramuscular injections of 250 mg of 17P or matching placebo, starting at 16 to 20 weeks of gestation and ending at 35 weeks. The primary study outcome was delivery or fetal death before 35 weeks of gestation.


RESULTS
Six hundred sixty-one women were randomly assigned to treatment. Baseline demographic data were similar in the two study groups. Six women were lost to follow-up; data from 655 were analyzed (325 in the 17P group and 330 in the placebo group). Delivery or fetal death before 35 weeks occurred in 41.5% of pregnancies in the 17P group and 37.3% of those in the placebo group (relative risk, 1.1; 95% confidence interval [CI], 0.9 to 1.3). The rate of the prespecified composite outcome of serious adverse fetal or neonatal events was 20.2% in the 17P group and 18.0% in the placebo group (relative risk, 1.1; 95% CI, 0.9 to 1.5). Side effects of the injections were frequent in both groups, occurring in 65.9% and 64.4% of subjects, respectively (P=0.69), but were generally mild and limited to the injection site.


CONCLUSIONS
Treatment with 17 alpha-hydroxyprogesterone caproate did not reduce the rate of preterm birth in women with twin gestations. (ClinicalTrials.gov number, NCT00099164 [ClinicalTrials.gov].).
Department of Obstetrics and Gynecology, Center for Women's Reproductive Health, University of Alabama at Birmingham, Birmingham 35249-7333, USA. drouse@uab.edu
Dwight J
DJ
Rouse
Steve N
SN
Caritis
Alan M
AM
Peaceman
Anthony
A
Sciscione
Elizabeth A
EA
Thom
Catherine Y
CY
Spong
Michael
M
Varner
Fergal
F
Malone
Jay D
JD
Iams
Brian M
BM
Mercer
John
J
Thorp
Yoram
Y
Sorokin
Marshall
M
Carpenter
Julie
J
Lo
Susan
S
Ramin
Margaret
M
Harper
Garland
G
Anderson
D000077713:17 alpha-Hydroxyprogesterone Caproate; D000328:Adult; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006908:Hydroxyprogesterones / Q000009:adverse effects / Q000627:therapeutic use*; D007273:Injections, Intramuscular; D011247:Pregnancy; D011256:Pregnancy Outcome; D011272:Pregnancy, Multiple; D047928:Premature Birth / Q000517:prevention & control*; D045167:Progesterone Congeners / Q000009:adverse effects / Q000627:therapeutic use*; D017211:Treatment Failure; D014427:Twins
D006908:Hydroxyprogesterones; D045167:Progesterone Congeners; D000077713:17 alpha-Hydroxyprogesterone Caproate