Menstrual induction with PGF2 alpha and PGE2

Prostaglandins for first-trimester termination

Since the 1980s, when mifepristone combined with a prostaglandin was found to be safe and effective for early abortion, many studies have refined the regimens and investigated alternatives such as methotrexate plus misoprostol, and misoprostol alone. Evidence now demonstrates that more than 200 mg of mifepristone provides no additional benefit, that vaginal misoprostol is superior to oral, especially between 7 and 9 weeks' gestation, and that misoprostol may be safely self-administered at home. Buccal and sublingual routes of administration of misoprostol also are promising. Absolute contraindications to medical abortion arise infrequently. Gastrointestinal and other side-effects occur in about one-third of women, primarily after administration of the prostaglandin. Careful assessment before and after medical abortion is essential and can be accomplished in various ways, depending on the skills of the clinician.

Medical abortion regimens: historical context and overview

Medical abortion offers an important alternative to surgical abortion for women with early pregnancies who wish to avoid a surgical procedure. More than 3 million women worldwide have had medical abortions in the past decade alone. The best-studied regimens include mifepristone orally followed 36 to 48 hours later by a prostaglandin analog administered either orally or intravaginally. Because of political and social restrictions related to mifepristone, however, researchers have investigated alternative regimens, most notably methotrexate and misoprostol. Mifepristone regimens are approximately 95% effective for abortion at </=49 days' gestation. Efficacy between 50 and 63 days' gestation varies according to the type and route of administration of the prostaglandin analog. Complete abortion rates among these later gestations are clinically acceptable when mifepristone is followed by intravaginally administered misoprostol or gemeprost. This report reviews the development, efficacy, and side effects of mifepristone regimens.

Arbaprostil's [15(R)-15-methyl PGE2] effects on intrauterine pressure in the nonpregnant and pregnant human female--a report of four clinical trials

Four clinical trials evaluating arbaprostil's effects on the human uterus are reported. The initial two trials measured intrauterine pressures in nonpregnant and pregnant human females following arbaprostil doses of 10, 25, and/or 50 mcg. No statistical differences were found at any dosage level in either study for average uterine resting pressures, average peak pressures, the number of contractions or Montevideo units. Subsequently, two trials determined the abortifacient potential of arbaprostil in pregnant women during the first trimester. The first utilized total daily doses of 400 and 800 mcgs. while the second used total daily doses of 1200 and 1600 mcgs. Vaginal spotting was noted in one woman receiving 400 mcgs, three receiving 1200 mcgs. and in two receiving 1600 mcgs. One episode of moderate bleeding was seen in the latter study. Based on these studies, arbaprostil exhibits little potential for inducing abortifacient activity at these dosages in these patient populations.

Early pregnancy termination: a comparison between vacuum aspiration and medical abortion using prostaglandin (16,16 dimethyl-trans-delta 2-PGE1 methyl ester) or the antiprogestogen RU 486

Three different regimens for termination of early pregnancy by medical means were compared to vacuum aspiration. Women seeking therapeutic abortion of pregnancy (less than or equal to 56 days amenorrhoea) were allocated to one of four treatment groups: (1) vacuum aspiration (n = 28); (2) 1 mg vaginal pessary of a prostaglandin analogue (gemeprost) every 3 h for up to 5 pessaries (n = 30); (3) the antigestogen (RU 486--mefipristone) 150 mg per day for 4 days by mouth (n = 20); (4) RU 486 in the same dose as group 3 together with 1 mg gemeprost on day 3 (n = 19). Complete abortion occurred more often in women treated with vacuum aspiration (96%), gemeprost alone (97%) and RU 486 plus gemeprost (95%) than in those treated with RU 486 alone (60%). In women receiving up to five gemeprost pessaries alone vomiting occurred in 7 (23%) and diarrhoea in 10 (33%); 16 (53%) required parenteral opiates for relief of pain. Side-effects and analgesic requirements were much reduced in the women who received RU 486 alone or in combination with a single gemeprost pessary. There was no difference in the number of days of vaginal bleeding after abortion between the four groups although there was wide individual variation (mean 10 days, range 1-34). These results confirm that medical induction of abortion in early pregnancy with prostaglandin vaginal pessaries is as effective as vacuum aspiration and that the dose can be reduced five-fold without loss of efficacy when used in combination with RU 486.

Therapeutic abortion in early pregnancy with antiprogestogen RU486 alone or in combination with prostaglandin analogue (gemeprost)

Abortion was attempted in 39 women in early pregnancy (less than 56 days amenorrhea) with the progesterone antagonist RU486 alone (150 mg per day for 4 days) or in combination with a PG analogue, 16,16-dimethyl-trans-delta 2-PGE1 (Gemeprost) in the form of a 1 mg vaginal pessary. Complete abortion was also attempted in 5 women who received RU486 together with 2 X 1 mg PG pessaries. Vaginal bleeding followed by complete abortion occurred in 18 of 19 women who received RU486 + 1 mg PG pessary as compared to only 12 of 20 women who received RU486 alone (P less than 0.01). All women who received RU486 + 2 mg Gemeprost had a complete abortion. The onset of crampy abdominal pain (median: 3 vs 4 days) and vaginal bleeding (3 vs 3 days) was similar in the RU486 and RU486 + PG groups, respectively. Slightly less than half the patients in both groups had nausea and/or vomiting, but the incidence did not differ from that occurring prior to treatment. The mean duration (range) of vaginal bleeding [RU486 alone: 10 (0,29) days and RU486 + PG: (5,34) days], and the measured blood loss [RU486: 53 (2,227) ml and RU486 + PG: 81 (32,222) ml] did not differ significantly between the two treatments. It is concluded that the combination of RU486 and a single PG vaginal pessary is a highly effective means of inducing therapeutic abortion in early pregnancy and offers an alternative to surgery.

A controlled release form of 16,16-dimethyl-trans-delta 2-PGE, methyl ester for early abortion

The termination of early pregnancy (less than 56 days amenorrhoea) has been investigated using 16,16-dimethyl-trans-delta 2-PGE, methyl ester in a controlled release preparation. The onset of crampy abdominal pain was seen after 270 +/- 39 minutes and bleeding occurred after 603 +/- 95 minutes. Two (15%) patients required no pain relief during treatment, however 5 (38%) requested oral analgesia, and in 6 (46%) individuals the pain was severe enough to warrant parenteral opiates. The overall success rate for complete abortion was 85%. No serious adverse effects were seen, but vomiting occurred in 2 (15%) women, and diarrhoea in 3 (23%). Although the use of this prostaglandin analogue in slow release form provides an effective treatment method for early abortion using a reduced total dose of prostaglandin, the acceptability of the drug as an agent for menstrual induction continues to be limited by the occurrence of troublesome gastro-intestinal side effects.

Ectopic pregnancy among early abortion patients: does prostaglandin reduce the incidence?

The availability and efficacy of prostaglandin (PG) F2 alpha and E series analogues has prompted their frequent use for pregnancy interruption. In the course of evaluating our experience with PGs for interrupting early first trimester gestations, we became increasingly impressed by the absence of any with extrauterine pregnancy. A review of 63 reports encompassing 2,965 patients whose pregnancies were less than 8 weeks' gestational age dating from the last menstrual period and who were similarly treated yielded only 2 cases of ectopic pregnancy. When compared with the generally accepted ectopic gestation rates of the order of 1 in 200 pregnancies, this frequency of 1 in 1,483 is unexpectedly low. Preselection does not appear to explain this impressive discrepancy. If the observation proves correct, it implies that PGs have some form of therapeutic effect in eradicating extrauterine pregnancy by nonoperative means. The implications are obvious in terms of its potential therapeutic benefits.

The use of 16-16 dimethyl trans delta 2 PGE1 methyl ester (ONO 802) vaginal suppositories for the termination of early pregnancy. A comparative study

Vaginal suppositories containing the 16-16 dimethyl trans delta 2 PGE1 methyl ester (ONO 802) were used for the induction of abortion in early pregnancy, and this non-surgical technique was compared with suction termination performed under local anaesthesia or general anaesthesia. Ninety patients were recruited to the study and divided equally between the three groups. Complete abortion was induced in 87 per cent of the patients treated with ONO 802 suppositories, which compared favourably with 87 and 100 per cent for the patients who had suction terminations under local anaesthesia and general anaesthesia respectively. The vaginal suppositories induced uterine bleeding in all patients and the mean time of onset of lower abdominal pain was 2 hours 55 minutes. The average numbers of episodes of vomiting and diarrhoea for patients given ONO 802 suppositories were 0.9 and 0.7 respectively. Menstrual blood loss was measured objectively in all groups and no significant differences between the three methods could be found. In selected cases, ONO 802 vaginal suppositories would seem to be safe and reasonably effective for the termination of early pregnancy.

Treatment with a single vaginal suppository containing 15-methyl PGF2 alpha methyl ester at expected time of menstruation

Termination of early pregnancy, by vaginal administration of prostaglandin analogues, one to three weeks after the first missed menstrual period, has advantages and disadvantages in comparison with vacuum aspiration. Some of these may be reduced if the patient is treated earlier. In the present study the effect and safety of one vaginal administration of 2.5 to 3 mg 15-methyl-PGF2 alpha methyl ester around the expected time of menstruation was evaluated in 16 women exposed to the risk of pregnancy. The overall number of treatment cycles was 35 and pregnancy was confirmed by plasma beta-HCG in eight. The treatment resulted in bleeding in all the pregnant cycles while in the nonpregnant ones it only provoked spotting and bleeding did not begin until the expected time of menstruation. Treatment with 2.5 mg 15-methyl-PGF2 alpha methyl ester resulted in complete abortion in one of three women. If the dose was increased to 3 mg all five treated women aborted. In nonpregnant patients no changes in the levels of estradiol-17 beta or progesterone at any time during the 24-hour observation period were found. Serum cortisol and prolactin but not TSH levels started to increase two hours after the start of treatment and reached a maximum after five hours. The increase coincided with the onset of uterine pain. Ovulatory cycles as judged from basal body temperature occurred in the first menstrual cycle following treatment in all nonpregnant patients. Although possible to use as a "once a month treatment" it seems preferable since the dose is the same, to postpone treatment until menstruation is delayed for a week or more.

Termination of early pregnancy by ONO-802 suppositories (16,16-dimethyl-trans-delta2-PGE1 methyl ester)

ONO-802 was used in the form of vaginal suppositories for the termination of early pregnancy in 63 healthy volunteers. Fifty-four (86%) of the 63 cases had complete abortions and remaining 9 (14%) had incomplete abortions. One (1.6%) of the 63 cases complained of nausea and vomiting, and 3 (4.8%) complained of headaches. No other side effects were observed. These results suggest that ONO-802 is acceptable in the form of vaginal suppositories for the termination of early pregnancy.

Termination of early pregnancy by ONO-802 (16,16-dimethyl-trans-delta2-PGE1 methyl ester)

ONO-802 was infused into the uterine cavity for the termination of early pregnancy in 45 healthy volunteers. Forty two (93%) of the 45 cases had complete abortions and two had incomplete abortions. Nine (20%) of the 45 volunteers complained of nausea, 7 (16%) vomited and 5 (11%) complained of abdominal pain. Neither diarrhea nor weakness was observed. These results suggest that ONO-802 is more acceptable for the termination of early pregnancy than is PGF2alpha.

Effects of PGF2alpha and PGF2alpha, 1-15 lactone on the corpus luteum and on early pregnancy in the rhesus monkey

The effects of prostaglandin (PG)F2alpha and PGF2alpha, 1-15 lactone were compared in luteal phase, non-pregnant and in early pregnant rhesus monkeys. Animals treated with either PG after pretreatment with human chorionic gonadotropin (hCG) had peripheral plasma progesterone concentrations that were not statistically different from those in animals treated with hCG and vehicle. However, menstrual cycle lengths in monkeys treated with PGF2alpha, 1-15 lactone were significantly (P less than 0.02) shorter than those in vehicle treated animals. In the absence of hCG pretreatment, plasma progesterone concentrations were significantly (P less than 0.008) lower by the second day after the initial treatment with either PGF2alpha or PGF2alpha, 1-15 lactone than in vehicle treated monkeys. Menstrual cycle lengths in monkeys treated with either PG were significantly (P less than 0.04) shorter than those in animals treated with vehicle. There were no changes in plasma progesterone concentrations in early pregnant monkeys treated with PGF2alpha, and pregnancy was not interrupted. In contrast, plasma progesterone declined and pregnancy was terminated in 5 of 6 early pregnant monkeys treated with PGF2alpha, 1-15 lactone. These data indicate that PGF2alpha, 1-15 lactone decreases menstrual cycle lengths in non-pregnant rhesus monkeys. More importantly, PGF2alpha, 1-15 lactone terminates early pregnancy in the monkey at a dose which is less than an ineffective dose of PGF2alpha.

Menstrual induction by the vaginal application of ICI 81008 gel

After approximately 2 weeks menstrual delay (positive Pregnosticon Tests) "menstrual induction" was attempted in 75 gravidas by repeated vaginal application of a gel, containing 200 or 400 mug/ml ICI 81008. After approximately 10 minutes, following the 1st vaginal delivery of 400 mug ICI 81008, the uterus responded to this PGF2alpha analogue with sustained contracture. The highest success rate in induced bleeding (93%) and pregnancy termination (79%), without supportive therapy, was achieved when 400 mug ICI 81008 was administered 2 to 5 times at 4 hour intervals. Those gravidas (21%), who failed in induced menstruation, or stopped bleeding within 24 hour- after treatment, had positive Pregnosticon Tests on day 14 and were curetted. The side effects, mostly vomiting and increased blood pressure, were transient and subjectively and medically acceptable. While the vaginal application of the drug is apparently less effective than the intrauterine (1), it has the advantage of simple delivery and the potential of self-administration.

Menstrual induction with the PGF2alpha-analogue ICI 81008

"Menstrual Induction" (MI) has been studied in 79 volunteers, using the therapeutic principle of "PG-Impact". The PGF2alpha analogue: ICI 81008 was administered under strictly aseptic precautions into the uterine cavity during the 4th week of pregnancy. The treatment catheter (inserted through the cervical canal) delivered a single dose of only 100-200 mug ICI 81008 during the pilot study with this new drug. When it was established that the side effects were acceptable, this moderately effective dose was increased at first to 200-300 mug and eventually to 400 mug. At the 400 mug dose level, 29 (76%) of the 38 study patients had complete and 8 (21%) incomplete abortions, while 1 (3%) failed to bleed. Those 9 women who had incomplete abortions or failed to abort were curetted. In comparison with PGF2alpha (428 cases) and PGE2 (114 cases), ICI 81008 (38 cases at the 400 mug level) provoked lesser side effects, excepting the transient increase in blood pressure. All patients (whose intrauterine pressure was measured) responded to the ICI 81008-impact with rapidly developing high level uterine contracture. Plasma progesterone decreased significantly if treatment was successful and insignificantly in cases of treatment failure. In current studies, the efficacy of the vaginal delivery system of ICI 81008 is examined.