Developing applications of prostaglandins in obstetrics and gynecology

A randomized comparison of two regimens of misoprostol for second-trimester pregnancy termination

OBJECTIVE

The purpose of this study was to compare the efficacy and side effects of two different misoprostol regimens for second-trimester pregnancy termination.

STUDY DESIGN

We performed a randomized clinical trial in patients who were at 14 to 23 weeks of gestation and who were admitted for medical termination of pregnancy. All patients received 800 microg of vaginal misoprostol and were assigned randomly to 400 microg of oral misoprostol or 400 microg of vaginal misoprostol every 8 hours. Efficacy and side effects were compared. The mean induction time of the study group was compared with that of an historic control group that had received 400 microg vaginally every 12 hours.

RESULTS

Forty-three women were assigned randomly, 22 women to vaginal misoprostol and 21 women to oral misoprostol. Induction time and hospital stay were slightly shorter for the oral group; however, the differences were not significant. Side effects were similar for both groups.

CONCLUSION

After an initial 800 microg dose of vaginal misoprostol, a regimen of 400 microg of oral misoprostol every 8 hours is as effective as the same dose of vaginal misoprostol with no additional side effects, which provides a convenient alternative for midtrimester pregnancy termination.

Developmental toxicity of alprostadil in rats after subcutaneous administration or intravenous infusion

Timed-pregnant Upj:TUC(SD)spf (Sprague-Dawley) rats were dosed with alprostadil (prostaglandin E1), either subcutaneously on Days 6-15 of gestation at 0.0, 0.5, 1.0, or 2.0 mg/kg/day or by iv infusion into the jugular vein (24 hr/day) on Days 7-15 at 0.0, 0.5, 1.0, 2.0, 4.0, or 6.0 mg/kg/day. Maternal toxicity was observed in all dams receiving alprostadil subcutaneously, the severity of which increased in a dose-related manner. Toxicity also was evident in the offspring in the 2.0 mg/kg/day group as evidenced by a significant increase in the percentage of resorptions and a significant decrease in the percentage of live fetuses. Mean fetal weight was significantly depressed in all three alprostadil-treated groups and several skeletal and visceral variations were significantly higher in the 1.0 and 2.0 mg/kg/day groups than in the vehicle control group; in addition, there were two instances of significantly increased frequencies of skeletal variations in the 0.5 mg/kg/day group. Gross, visceral, and skeletal malformations were significantly increased in the high-dose group. During iv infusion of alprostadil more than 50% of the dams in the 6.0 mg/kg/day group died and there was one death in the 4.0 mg/kg/day group. Significant decreases in maternal weight gain between Days 7 and 11 of gestation were observed at doses of 1.0 mg/kg/day and above. However, continuous iv infusion of this prostaglandin, at dosages which were not severely toxic to the dams, was judged not to be teratogenic or otherwise embryotoxic in rats. The increase in uterine contractions, observed at 1.0 and 2.0 mg/kg after sc administration to rats implanted with chronic uterine microballoons, was consistent with the hypothesis that the developmental toxicity observed after bolus sc administration was the consequence of decreased blood flow in the uterus and/or placenta and/or embryos.

Hydrogen peroxide induces spawning in mollusks, with activation of prostaglandin endoperoxide synthetase

Addition of hydrogen peroxide to seawater causes synchronous spawning in gravid male and female abalones, and certain other mollusks as well. This effect is blocked by exposure of the animals to aspirin, an inhibitor of the enzyme catalyzing oxidative synthesis of prostaglandin endoperoxide. Hydrogen peroxide activates this enzymatic reaction in cell-free extracts prepared from abalone eggs (a very rich source of the prostaglandin endoperoxide synthetase); this effect appears to reveal a fundamental property of prostaglandin endoperoxide synthesis. Applicability of these findings to both mariculture and medical purposes is suggested.

Induction of labor with intravenous prostaglandin

The present study utilizing an open label design evaluates the efficacy of prostaglandin F2alpha in the induction of labor in normal and complicated primigravid and multigravid pregnancies and in particular in patients with an unripe cervix. The results reveal that labor was successfully induced in 33 of 38 (86.8 per cent) normal patients in the 0 to 5 Bishop group and in 17 of 18 (94.4 per cent) in the 6 to 13 Bishop group. In the complicated pregnancies (abnormal group) 26 to 28 (84 per cent) in the 0 to 5 Bishop group and 13 of 13 (100 per cent) in the 6 to 13 Bishop group were successfully induced. There were two cesarean sections for obstetric indications. Hypertonus occurred only four times and responded to dose reduction. The most common problem--nausea and vomiting (29 per cent)--was easily controlled. Prostaglandin when judiciously used appears to be a safe drug for the induction of labor at term in normal as well as complicated pregnancies and in patients with low inducibility scores.