Cervical length changes during preterm cervical ripening: effects of 17-alpha-hydroxyprogesterone caproate. The use of micronized progesterone in the treatment of menace of preterm delivery. Treatment of threatened premature labor with large doses of progesterone. The effects of oral administration of progesterone for premature labor.
The purpose of this study was to evaluate whether 17-alpha-hydroxyprogesterone caproate (17P) treatment affect changes in cervical length.
                Women with singleton pregnancy, between 25 and 33 + 6 weeks of gestation, who were hospitalized for preterm labor were included. Patients with rupture of membranes and/or signs of chorioamnionitis were excluded. Sixty undelivered patients were allocated randomly to either observation or to receive 341 mg of 17P intramuscularly, twice each week until gestational week 36. Cervical length was measured by transvaginal ultrasound scanning at discharge and at day 7 and 21 after discharge. Statistical comparisons were done with analysis of variance and chi-square test.
                Shortening of the cervix in the observation group (30 cases) was higher than in the 17P group (30 cases) both at day 7 (2.37 +/- 2.0 mm vs 0.83 +/- 1.74 mm; P = .002) and day 21 (4.60 +/- 2.73 mm vs 2.40 +/- 2.46 mm; P = .002). Treatment with 17P was associated with both a reduction in the risk of cervical shortening of > or = 4 mm (odds ratio, 0.18; 95% CI, 0.04-0.66) and in the risk of preterm delivery (odds ratio, 0.15; 95% CI, 0.04-0.58).
                Undelivered patients after preterm labor undergo progressive shortening of the cervix, which is attenuated by 17P treatment. The results of a study concerning the treatment of acute menace of preterm labor are given: beta-mimetics were administered intravenously in all cases (44) and micronized progesterone or placebo was administered orally after classical double-blind randomization (22 cases in each group). The mean index of pregnancy prolongation was the same in both groups. However the mean duration of the intravenous perfusion and the mean quantity of beta-mimetics administered intravenously were significantly reduced in the progesterone group (P less than 0.01). The mean duration of hospital stay was also significantly reduced (P less than 0.05). Cost and risks are finally significantly lessened. nan The potential tocolytic effect of natural progesterone administration on premature labor was investigated in a double-blind study. An oral progesterone formulation was used because its ability to increase both plasma and myometrial concentration of progesterone in pregnant women had been previously demonstrated. Furthermore, no commercial intravenous or intramuscular natural progesterone formulation is currently available in France. Fifty-seven patients in two obstetric clinics, admitted because of the risk of premature delivery, were included in the study, and uterine contractility and fetal cardiac rhythm were monitored in all of them. At random and after 30 minutes' rest, 29 women absorbed four capsules of 100 mg of progesterone each and 28 women absorbed four capsules of a placebo. Plasma progesterone levels were evaluated in all cases after 30 minutes' rest and 1 hour after absorption of the capsules. The results showed that bed rest and placebo administration decrease uterine activity in 42% of the cases and oral progesterone decreases activity in 75% to 88% of cases, depending on the initial severity of the menace of premature delivery. The difference between the effects of progesterone and of placebo is significant. The tocolytic effect of oral progesterone is not as intense or as rapid as the effect of intravenous beta-mimetics but is sufficient in 80% of cases, on the average, to stop the premature labor without any detectable side effects. This tocolytic effect of oral progesterone is related not just to an increase in plasma progesterone levels but probably to an increase in myometrial progesterone concentration.
Currently, there is insufficient evidence to advocate progestational agents as a tocolytic agents for women presenting with preterm labour.