Progesterone vaginal gel for the reduction of recurrent preterm birth: primary results from a randomized, double-blind, placebo-controlled trial. Inefficacy of 17 alpha-hydroxyprogesterone caproate in the prevention of prematurity in twin pregnancy. The effect of 17 alpha-hydroxyprogesterone caproate on pregnancy outcome in an active-duty military population. 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. A trial of 17 alpha-hydroxyprogesterone caproate to prevent prematurity in twins. Progesterone for maintenance tocolytic therapy after threatened preterm labour: a randomised controlled trial. Prevention of recurrent preterm delivery by 17 alpha-hydroxyprogesterone caproate.
Preterm birth is the leading cause of perinatal morbidity and mortality worldwide. Treatment of preterm labor with tocolysis has not been successful in improving infant outcome. The administration of progesterone and related compounds has been proposed as a strategy to prevent preterm birth. The objective of this trial was to determine whether prophylactic administration of vaginal progesterone reduces the risk of preterm birth in women with a history of spontaneous preterm birth.
                This randomized, double-blind, placebo- controlled, multinational trial enrolled and randomized 659 pregnant women with a history of spontaneous preterm birth. Between 18 + 0 and 22 + 6 weeks of gestation, patients were assigned randomly to once-daily treatment with either progesterone vaginal gel or placebo until either delivery, 37 weeks' gestation or development of preterm rupture of membranes. The primary outcome was preterm birth at </= 32 weeks of gestation. The trial was analyzed using an intent-to-treat strategy.
                Baseline characteristics were similar in the two treatment groups. Progesterone did not decrease the frequency of preterm birth at </= 32 weeks. There was no difference between the groups with respect to the mean gestational age at delivery, infant morbidity or mortality or other maternal or neonatal outcome measures. Adverse events during the course of treatment were similar for the two groups.
                Prophylactic treatment with vaginal progesterone did not reduce the frequency of recurrent preterm birth (</= 32 weeks) in women with a history of spontaneous preterm birth. The effect of progesterone administration in patients at high risk for preterm delivery as determined by methods other than history alone (e.g. sonographic cervical length) requires further investigation.
                Copyright (c) 2007 ISUOG There are indications that prophylactic administration of 17 alpha-hydroxyprogesterone caproate (17 alpha-OHP-C) could be beneficial in the treatment of women at risk for preterm delivery. Since twin pregnancy is commonly associated with prematurity, 77 women with twin pregnancy were treated during the last trimester until the 37th gestational week with weekly injections of either 17 alpha-OHP-C or a placebo, following double-blind principles. The gestational length and birth weight and the outcome of the neonates were similar in both groups. The administration of 17 alpha-OHP-C thus seems ineffective in the prevention of prematurity risks associated with twin pregnancy. A prior report suggested that active-duty pregnant women are at increased risk for low-birth weight infants and a higher perinatal mortality rate. The present double-blind investigation was designed to prospectively evaluate that risk and to test the efficacy of 17 alpha-hydroxyprogesterone caproate to prevent reported complications. Three groups of active-duty women were studied, beginning between 16 and 20 weeks' gestation. They were similar for parity, previous abortion, race, cigarette smoking, and marital status. Of these, 80 were given 17 alpha-hydroxyprogesterone caproate, 88 received placebo, and 78 declined to participate in the protocol. There was no significant differences in the three groups when comparisons were made for low-birth weight infants and for perinatal mortality. However, when comparison was made to a military dependent population, they had a significantly worse outcome with regard to both perinatal mortality (p = 0.001) and infants with a birth weight less than 2,500 gm (p = 0.01). We concluded that pregnant military personnel were at increased risk for adverse pregnancy outcome, but that this risk was not altered by therapy with 17 alpha-hydroxyprogesterone caproate. The purpose of this study was to evaluate the effect of prophylactic vaginal progesterone in decreasing preterm birth rate in a high-risk population.
                A randomized, double-blind, placebo-controlled study included 142 high-risk singleton pregnancies. Progesterone (100 mg) or placebo was administered daily by vaginal suppository and all patients underwent uterine contraction monitoring with an external tocodynamometer once a week for 60 minutes, between 24 and 34 weeks of gestation. Progesterone (n = 72) and placebo (n = 70) groups were compared for epidemiologic characteristics, uterine contraction frequency, and incidence of preterm birth. Data were compared by chi(2) analysis and Fisher exact test.
                The preterm birth rate was 21.1% (30/142). Differences in uterine activity were found between the progesterone and placebo groups (23.6% vs 54.3%, respectively; P <.05) and in preterm birth between progesterone and placebo (13.8% vs 28.5%, respectively; P <.05). More women were delivered before 34 weeks in the placebo group (18.5%) than in the progesterone group (2.7%) (P <.05).
                Prophylactic vaginal progesterone reduced the frequency of uterine contractions and the rate of preterm delivery in women at high risk for prematurity. 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.
                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.
                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.
                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].).
                Copyright 2007 Massachusetts Medical Society. Women with preterm labour that is arrested with tocolytic therapy are at increased risk of recurrent preterm labour. The efficacy of maintenance tocolytic therapy after successful arrest of preterm labour remains controversial.
                The purpose of this study was to determine whether supplementation of vaginal progesterone after inhibition of preterm labour is associated with an increased latency period and a decreased recurrent of preterm labour.
                This trial was conducted in 70 women who presented with symptoms of threatened preterm labour, who after arrest of uterine activity were then randomised to progesterone therapy or no treatment. Treatment group received progesterone suppository (400 mg) daily until delivery and control group received no treatment.
                Longer mean latency until delivery (36/11 +/- 17/9 vs 24/52 +/- 27/2) (mean + standard deviation) days; respiratory distress syndrome 4 (10.8%) vs 12 (36.4%) P = 0.021; low birthweight 10 (27%) vs 17 (51.5%) P = 0.04; and birthweight (3101.54 +/- 587.9 g vs r 2609.39 +/- 662.9 g, P = 0.002), were significantly different between the two groups. No significant differences were found between recurrent preterm labour 13 (35.1%) vs 19 (57.6%), P = 0.092; admission to intensive care unit 9 (24.3%) vs 13 (39.4%), P= 0.205 ; and neonatal sepsis 2 (5.4%) vs 6 (18.2%) P = 0.136, for the progesterone and control groups, respectively.
                The use of vaginal progesterone suppository after successful parenteral tocolysis associated with a longer latency preceding delivery but failed to reduce the incidence of readmission for preterm labour. Women who have had a spontaneous preterm delivery are at greatly increased risk for preterm delivery in subsequent pregnancies. The results of several small trials have suggested that 17 alpha-hydroxyprogesterone caproate (17P) may reduce the risk of preterm delivery.
                We conducted a double-blind, placebo-controlled trial involving pregnant women with a documented history of spontaneous preterm delivery. Women were enrolled at 19 clinical centers at 16 to 20 weeks of gestation and randomly assigned by a central data center, in a 2:1 ratio, to receive either weekly injections of 250 mg of 17P or weekly injections of an inert oil placebo; injections were continued until delivery or to 36 weeks of gestation. The primary outcome was preterm delivery before 37 weeks of gestation. Analysis was performed according to the intention-to-treat principle.
                Base-line characteristics of the 310 women in the progesterone group and the 153 women in the placebo group were similar. Treatment with 17P significantly reduced the risk of delivery at less than 37 weeks of gestation (incidence, 36.3 percent in the progesterone group vs. 54.9 percent in the placebo group; relative risk, 0.66 [95 percent confidence interval, 0.54 to 0.81]), delivery at less than 35 weeks of gestation (incidence, 20.6 percent vs. 30.7 percent; relative risk, 0.67 [95 percent confidence interval, 0.48 to 0.93]), and delivery at less than 32 weeks of gestation (11.4 percent vs. 19.6 percent; relative risk, 0.58 [95 percent confidence interval, 0.37 to 0.91]). Infants of women treated with 17P had significantly lower rates of necrotizing enterocolitis, intraventricular hemorrhage, and need for supplemental oxygen.
                Weekly injections of 17P resulted in a substantial reduction in the rate of recurrent preterm delivery among women who were at particularly high risk for preterm delivery and reduced the likelihood of several complications in their infants.
                Copyright 2003 Massachusetts Medical Society
Further trials are required to assess the benefits and harms of progesterone therapy when given to women considered to be at increased risk of early birth.
[Note: The 52 citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.]