Preterm Birth · Progesterone Prophylaxis
da Fonseca EB et al., 2003 · Am J Obstet Gynecol
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.
Labor and Birth · Physiologic Birth
Zalar RW Jr, 1996 · Obstet Gynecol
To characterize the continuum between normal and preterm labor to prevent spontaneous preterm birth and low birth weight. Between August 1, 1992, and November 30, 1993, obstetric patients from a large managed care medical group were assigned in rotation to five private practice offices for pregnancy care. In the study office (374 births), a systematic approach of visit-by-visit screening, patient education, selective office evaluation of cervical change by transvaginal ultrasound examination, outpatient modification of activity, and graded oral or subcutaneous tocolysis was used; inpatient tocolysis was used only when outpatient management failed. In the comparison offices (1391 births), transvaginal ultrasound was not used and conventional methods were used at the discretion of the attending physicians. Birth weights below 1500 g (P = .008; odds ratio [OR] 0.08, 95% confidence interval [CI] 0.05-1.32), 2000 g (P = .21; OR 0.21, 95% CI 0.05-0.88), and 2500 g (P = .008; OR 0.44, 95% CI 0.23-0.83) occurred significantly less often in the study group than in the comparison group. The difference in spontaneous preterm births under 2500 g was also significant (P < .001; OR 0.08, 95% CI 0.01-0.58). By emphasizing transvaginal ultrasound and graded outpatient tocolysis, the diagnosis and management of preterm prelabor was associated with a reduction in the rate of spontaneous preterm birth and low birth weight infants.
Preterm Birth · Progesterone Prophylaxis
ACOG, 2003 · Obstet Gynecol
Preterm birth affects 12% of all births in the United States. Recent studies support the hypothesis that progesterone supplementation reduces preterm birth in a select group of women (ie, those with a prior spontaneous birth at <37 weeks of gestation). Despite the apparent benefits of progesterone in this high-risk population, the ideal progesterone formulation is unknown. The American College of Obstetricians and Gynecologists Committee on Obstetric Practice believes that further studies are needed to evaluate the use of progesterone in patients with other high-risk obstetric factors, such as multiple gestations, short cervical length, or positive test results for cervicovaginal fetal fibronectin. When progesterone is used, it is important to restrict its use to only women with a documented history of a previous spontaneous birth at less than 37 weeks of gestation because unresolved issues remain, such as optimal route of drug delivery and long-term safety of the drug.