Modification of vascular responsiveness to angiotensin II in pregnant women by intravenously infused 5alpha-dihydroprogesterone

Williams Obstetrics, 21st Edition

Cunningham FG et al., 2001

Hormone production during pregnancy in the primigravid patient. I. Plasma levels of progesterone and 5-alpha-pregnane-3,20-dione throughout pregnancy of normal women and women who developed pregnancy-induced hypertension

Parker CR Jr et al., 1979 · Am J Obstet Gynecol

The plasma concentrations of progesterone and 5-alpha-pregnane-3,20-dione (5-alpha-dihydroprogesterone) were measured from as early as 12 weeks through 41 weeks of gestation in primigravid women. Two groups of primigravid women were assessed, those with uncomplicated pregnancies and those who developed pregnancy-induced hypertension. Plasma levels of progesterone and 5-alpha-dihydroprogesterone rose progressively throughout gestation in both groups of women. The ratio of the level of progesterone to that of 5-alpha-dihydroprogesterone in individual plasma samples of women with uncomplicated pregnancies was 7.0 from 12 to 15 weeks' gestation while at 35 to 41 weeks' gestation the ratio had declined to 4.6. Similar results were obtained in plasma samples of women who ultimately developed pregnancy-induced hypertension. Since no differences in plasma levels of progesterone or 5-alpha-dihydroprogesterone were detected between primigravid women with uncomplicated pregnancies and those who developed pregnancy-induced hypertension, we conclude that neither progesterone nor 5-alpha-dihydroprogesterone concentrations in plasma are of value in identifying women at risk of developing pregnancy-induced hypertension.

Isolation and characterization of 5alpha-pregnane-3,20-dione and progesterone in pepipheral blood of pregnant women. measurement throughout pregnancy

Milewich L et al., 1975 · Gynecol Invest

5alpha-Pregnane-3,20-dione and progesterone were isolated from a pregnancy plasma pool and were identified by using a combination of chromatographic techniques and mass spectrometry. Antibodies to progesterone were obtained in rabbits by immunization with progesterone-1alpha-carboxyethyl-thioether-thyroglobulin. The raised antibodies were of high affinity and one of them cross-reacted (137%) with 5alpha-pregnane-3,20-dione. This property was used to develop radioimmunoassays for measuring circulating levels of both progesterone and 5alpha-pregnane-3,20-dione in pregnancy plasma. The levels of both progesterone and 5alpha-pregnane-3,20-dione increase throughout pregnancy, but a highly significant increase is observed only after the 32nd week of gestation.

Prostaglandin-induced myometrial activity inhibited by progesterone

Porter DG et al., 1971 · Nature

PROSTAGLANDINS (PGs) are being used increasingly as abortifacients although their precise mechanism of action is uncertain. One of the compounds frequently used is PGF2α, which has been shown to stimulate the myometrium in vitro1 and in vivo2. Whether or not the direct action of this agent on the uterine muscle alone is responsible for the interruption of pregnancy is not clear, but the long interval between infusion and abortion3 suggests that other mechanisms might be involved; for example, a luteolytic effect4–6. The prompt increase in uterine activity after treatment with prostaglandin, however, argues that the direct effect plays some part in the abortifacient action. Little is known of the influence of other myometrial regulatory agents such as the ovarian steroids on the uterine response to PGs. Accordingly we examined the influence of progesterone on myometrial responses to prostaglandin F2α in the rabbit, a species in which progesterone is known to have a blocking action on the uterine muscle7.

Vaginal micronised progesterone for the prevention of hypertensive disorders of pregnancy: A systematic review and meta-analysis

Melo P et al., 2023 · BJOG · Free to read

Treatment with vaginal progesterone reduces the risk of miscarriage and preterm birth in selected high-risk women. The hypothesis that vaginal progesterone can reduce the risk of hypertensive disorders of pregnancy (HDP) is unexplored. To summarise the evidence on the effectiveness of vaginal progesterone to reduce the risk of HDP. Search Strategy: We searched Embase (OVID), MEDLINE (OVID), PubMed, CENTRAL and clinicaltrials.gov from inception until 20 June 2023. Selection Criteria: We included placebo-controlled randomised trials (RCTs) of vaginal progesterone for the prevention or treatment of any pregnancy complications. Data Collection and Analysis: We extracted absolute event numbers for HDP and pre-eclampsia in women receiving vaginal progesterone or placebo, and meta-analysed the data with a random effects model. We appraised the certainty of the evidence using GRADE methodology. MAIN The quantitative synthesis included 11 RCTs, of which three initiated vaginal progesterone in the first trimester, and eight in the second or third trimesters. Vaginal progesterone started in the first trimester of pregnancy lowered the risk of any HDP (risk ratio [RR] 0.71, 95% confidence interval [CI] 0.53-0.93, 2 RCTs, n = 4431 women, I(2) = 0%; moderate-certainty evidence) and pre-eclampsia (RR 0.61, 95% CI 0.41-0.92, 3 RCTs, n = 5267 women, I(2) = 0%; moderate-certainty evidence) when compared with placebo. Vaginal progesterone started in the second or third trimesters was not associated with a reduction in HDP (RR 1.19, 95% CI 0.67-2.12, 3 RCTs, n = 1602 women, I(2) = 9%; low-certainty evidence) or pre-eclampsia (RR 0.97, 95% CI 0.71-1.31, 5 RCTs, n = 4274 women, I(2) = 0%; low-certainty evidence). Our systematic review found first-trimester initiated vaginal micronised progesterone may reduce the risk of HDP and pre-eclampsia.

Hypotensive action of progesterone in experimental and human hypertension

Armstrong JG, 1959 · Proc Soc Exp Biol Med

Summary(1) Progesterone administration to rats and dogs with experimental hypertension and to humans with primary arterial hypertension resulted in a decline in blood pressure levels. Blood pressures increased once more in all cases after progesterone was discontinued. (2) In humans, but not necessarily in rats and dogs, blood pressure reduction would appear to have resulted from natruresis.

Serum progesterone and estradiol in pregnant women selected for progestagen treatment

Dubin NH et al., 1979 · Int J Fertil

Patients with two or more previous spontaneous second trimester abortions and vaginal cytology indicating a poor progestational response in current pregnancies were selected for treatment with Provera (medroxyprogesterone acetate) and/or Delalutin (17 alpha-hydroxyprogesterone caproate). Serum was examined serially for progesterone (P) and estradiol (E) by radioimmunoassay. Serum from 174 untreated patients with no known complications ranging from 6--40 weeks gestation provided normal distribution data. Of 14 progestagen-treated patients, four aborted during the second trimester. These all had chronically low (greater than 50% of observations were less than 1 standard deviation of the normal population) or falling P/E ratios. The rest delivered normal full-term infants although five of the 10 had chronically low P, seven had chronically low P/E ratios, and in one other P/E was falling. Chronically high E contributed to the low P/E ratio in three cases. Thus, these selected cases with poor obstetrical histories demonstrated steroid patterns outside the +/- 1 standard deviation range, although the steroid levels were still within the normal range. Serum progesterone and estradiol analysis may eventually be useful in identifying patients who will best respond to progestagen treatment.