Randomized, double-blind, controlled trial of mifepristone in capsule versus tablet form followed by misoprostol for early medical abortion

Combination of Mifepristone and Misoprostol for First-Trimester Medical Abortion: A Comprehensive Review of the Literature

Importance

Several medications have been used to achieve medical abortion in the first trimester of pregnancy. The most commonly used is the combination of mifepristone and misoprostol; however, different doses and routes of administration have been proposed.

Objective

The aim of this study was to summarize published data on the effectiveness, adverse effects, and acceptability of the various combinations of mifepristone and misoprostol in medical abortion protocols in the first trimester of pregnancy.

Evidence Acquisition

This was a comprehensive review, synthesizing the findings of the literature on the current use of mifepristone and misoprostol for first-trimester abortion.

Results

The combination of mifepristone and misoprostol seems to be more effective than misoprostol alone. Regarding the dosages and routes, mifepristone is administered orally, and the optimal dose is 200 mg. The route of administration of misoprostol varies; the sublingual and buccal routes are more effective; however, the vaginal route (800 μg) is associated with fewer adverse effects. Finally, the acceptability rates did not differ significantly.

Conclusions

Different schemes for first-trimester medical abortion have been described so far. Future research needs to focus on identifying the method that offers the best trade-off between efficacy and safety in first-trimester medical abortion.

Medical methods for first trimester abortion

BACKGROUND

Medical abortion became an alternative method of pregnancy termination following the development of prostaglandins and antiprogesterone in the 1970s and 1980s. Recently, synthesis inhibitors of oestrogen (such as letrozole) have also been used to enhance efficacy. The most widely researched drugs are prostaglandins (such as misoprostol, which has a strong uterotonic effect), mifepristone, mifepristone with prostaglandins, and letrozole with prostaglandins. More evidence is needed to identify the best dosage, regimen, and route of administration to optimise patient outcomes. This is an update of a review last published in 2011.

OBJECTIVES

To compare the effectiveness and side effects of different medical methods for first trimester abortion.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Global Health, and LILACs on 28 February 2021. We also searched Clinicaltrials.gov and the World Health Organization's (WHO) International Clinical Trials Registry Platform, and reference lists of retrieved papers.

SELECTION CRITERIA

We considered randomised controlled trials (RCTs) that compared different medical methods for abortion before the 12th week of gestation. The primary outcome is failure to achieve complete abortion. Secondary outcomes are mortality, surgical evacuation, ongoing pregnancy at follow-up, time until passing of conceptus, blood transfusion, side effects and women's dissatisfaction with the method.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected and evaluated studies for inclusion, and assessed the risk of bias. We processed data using Review Manager 5 software. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 99 studies in the review (58 from the original review and 41 new studies). 1. Combined regimen mifepristone/prostaglandin Mifepristone dose: high-dose (600 mg) compared to low-dose (200 mg) mifepristone probably has similar effectiveness in achieving complete abortion (RR 1.07, 95% CI 0.87 to 1.33; I2 = 0%; 4 RCTs, 3494 women; moderate-certainty evidence). Prostaglandin dose: 800 µg misoprostol probably reduces abortion failure compared to 400 µg (RR 0.63, 95% CI 0.51 to 0.78; I2= 0%; 3 RCTs, 4424 women; moderate-certainty evidence). Prostaglandin timing: misoprostol administered on day one probably achieves more success on complete abortion than on day three (RR 1.94, 95% CI 1.05 to 3.58; 1489 women; 1 RCT; moderate-certainty evidence). Administration strategy: there may be no difference in failure of complete abortion with self-administration at home compared with hospital administration (RR 1.63, 95% CI 0.68 to 3.94; I2 = 84%; 2263 women; 4 RCTs; low-certainty evidence), but failure may be higher when administered by nurses in hospital compared to by doctors in hospital (RR 2.69, 95% CI 1.39 to 5.22; I2 = 66%; 3 RCTs, 3056 women; low-certainty evidence). Administration route: oral misoprostol probably leads to more failures than the vaginal route (RR 2.38, 95% CI 1.46 to 3.87; I2 = 39%; 3 RCTs, 1704 women; moderate-certainty evidence) and may be associated with more frequent side effects such as nausea (RR 1.14, 95% CI 1.03 to 1.26; I2 = 0%; 2 RCTs, 1380 women; low-certainty evidence) and diarrhoea (RR 1.80 95% CI 1.49 to 2.17; I2 = 0%; 2 RCTs, 1379 women). Compared with the vaginal route, complete abortion failure is probably lower with sublingual (RR 0.68, 95% CI 0.22 to 2.11; I2 = 59%; 2 RCTs, 3229 women; moderate-certainty evidence) and may be lower with buccal administration (RR 0.71, 95% CI 0.34 to 1.46; I2 = 0%; 2 RCTs, 479 women; low-certainty evidence), but sublingual or buccal routes may lead to more side effects. Women may experience more vomiting with sublingual compared to buccal administration (RR 1.33, 95% CI 1.01 to 1.77; low-certainty evidence). 2. Mifepristone alone versus combined regimen The efficacy of mifepristone alone in achieving complete abortion compared to combined mifepristone/prostaglandin up to 12 weeks is unclear (RR of failure 3.25, 95% CI 0.81 to 13.09; I2 = 83%; 3 RCTs, 273 women; very low-certainty evidence). 3. Prostaglandin alone versus combined regimen Nineteen studies compared prostaglandin alone to a combined regimen (prostaglandin combined with mifepristone, letrozole, estradiol valerate, tamoxifen, or methotrexate). Compared to any of the combination regimens, misoprostol alone may increase the risk for failure to achieve complete abortion (RR of failure 2.39, 95% CI 1.89 to 3.02; I2 = 64%; 18 RCTs, 3471 women; low-certainty evidence), and with more diarrhoea. 4. Prostaglandin alone (route of administration) Oral misoprostol alone may lead to more failures in complete abortion than the vaginal route (RR 3.68, 95% CI 1.56 to 8.71, 2 RCTs, 216 women; low-certainty evidence). Failure to achieve complete abortion may be slightly reduced with sublingual compared with vaginal (RR 0.69, 95% CI 0.37 to 1.28; I2 = 87%; 5 RCTs, 2705 women; low-certainty evidence) and oral administration (RR 0.58, 95% CI 0.11 to 2.99; I2 = 66%; 2 RCTs, 173 women). Failure to achieve complete abortion may be similar or slightly higher with sublingual administration compared to buccal administration (RR 1.11, 95% CI 0.71 to 1.74; 1 study, 401 women).

AUTHORS' CONCLUSIONS

Safe and effective medical abortion methods are available. Combined regimens (prostaglandin combined with mifepristone, letrozole, estradiol valerate, tamoxifen, or methotrexate) may be more effective than single agents (prostaglandin alone or mifepristone alone). In the combined regimen, the dose of mifepristone can probably be lowered to 200 mg without significantly decreasing effectiveness. Vaginal misoprostol is probably more effective than oral administration, and may have fewer side effects than sublingual or buccal. Some results are limited by the small numbers of participants on which they are based. Almost all studies were conducted in settings with good access to emergency services, which may limit the generalisability of these results.

Mifepristone: a potential clinical agent based on its anti-progesterone and anti-glucocorticoid properties

Nowadays, unwanted pregnancy is a major globe tragedy for millions of women, associated with significant direct and indirect costs, no matter for individuals or society. The progesterone receptor antagonist steroid, mifepristone has been widely and effectively using throughout the world for medical abortion, but to a lesser extent for emergency contraception. In this review, we hope to explore the role of mifepristone as a contraceptive, particularly for emergency contraception. Studies of mifepristone have also been expanding to the fields of endometriosis and uterine fibroids. Furthermore, this initially considered reproductive medicine has been investigated in some psychotic diseases and various disorders of hypercortisolism, because of its glucocorticoid receptor antagonism. Mifepristone was approved suitable for patients with hyperglycemia secondary to Cushing's syndrome by the United States Food and Drug Administration (FDA) in 2012. The aim of this article is to review published reports on the anti-progesterone and anti-glucocorticoid properties of mifepristone as a clinical agent. There is a new insight into systematically describing and evaluating the potential efficiency of mifepristone administrated in the field of endocrine and neuroendocrine, not only in obstetrics and gynecology.

Medical methods for first trimester abortion

BACKGROUND

Surgical abortion by vacuum aspiration or dilatation and curettage has been the method of choice for early pregnancy termination since the 1960s. Medical abortion became an alternative method of first trimester pregnancy termination with the availability of prostaglandins in the early 1970s and anti-progesterones in the 1980s. The most widely researched drugs are prostaglandins (PGs) alone, mifepristone alone, methotrexate alone, mifepristone with prostaglandins and methotrexate with prostaglandins.

OBJECTIVES

To compare different medical methods for first trimester abortion.

SEARCH METHODS

The Cochrane Controlled Trials Register, MEDLINE and Popline were systematically searched. Reference lists of retrieved papers were also searched. Experts in WHO/HRP were contacted.

SELECTION CRITERIA

Types of studies Randomised controlled trials comparing different medical methods for abortion during first trimester (e.g. single drug, combination) were considered. Trials were assessed and included if they had adequate concealment of allocation, randomisation procedure and follow-up. Women, pregnant during the first trimester, undergoing medical abortion were the participants. The outcomes were mortality, failure to achieve complete abortion, surgical evacuation, ongoing pregnancy at follow-up, time until passing of conceptus, blood transfusion, side effects and women's dissatisfaction with the procedure.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials for inclusion from the results of the search strategy described previously.The selection of trials for inclusion in the review was performed independently by two reviewers after employing the search strategy described previously. Trials under consideration were evaluated for appropriateness for inclusion and methodological quality without consideration of their results. Data were processed using Revman software.

MAIN RESULTS

Fifty-eight trials were included in the review. The effectiveness outcomes below refer to 'failure to achieve complete abortion' with the intended method unless otherwise stated. 1) Combined regimen mifepristone/prostaglandin: Mifepristone 600 mg compared to 200 mg shows similar effectiveness in achieving complete abortion (4 trials, RR 1.07, 95% CI 0.87 to 1.32). Misoprostol administered orally is less effective (more failures) than the vaginal route (RR 3.00, 95% CI 1.44 to 6.24) and may be associated with more frequent side effects such as nausea and diarrhoea. Sublingual and buccal routes were similarly effective compared to the vaginal route, but had higher rates of side effects. 2) Mifepristone alone is less effective when compared to the combined regimen mifepristone/prostaglandin (RR 3.76 95% CI 2.30 to 6.15). 3) Five trials compared prostaglandin alone to the combined regimen (mifepristone/prostaglandin). All but one reported higher effectiveness with the combined regimen. The results of these studies could not be combined but the RR of failure with prostaglandin alone is reportedly between 1.4 to 3.75 with the 95% confidence intervals indicating statistical significance. 4) In one trial comparing gemeprost 0.5 mg with misoprostol 800 mcg, misoprostol was more effective (failure with gemeprost: RR 2.86, 95% CI 1.14 to 7.18). 5) There was no difference in effectiveness with use of a divided dose compared to a single dose of prostaglandin. 6) Combined regimen methotrexate/prostaglandin demonstrates similar rates of failure to complete abortion when comparing intramuscular to oral methotrexate administration (RR 2.04, 95% CI 0.51 to 8.07). Similarly, day 3 vs. day 5 administration of prostaglandin following methotrexate administration showed no significant differences (RR 0.72, 95% CI 0.36 to 1.43). One trial compared the effect of tamoxifen vs. methotrexate and no statistically significant differences were observed in effectiveness between the groups.

AUTHORS' CONCLUSIONS

Safe and effective medical abortion methods are available. Combined regimens are more effective than single agents. In the combined regimen, the dose of mifepristone can be lowered to 200 mg without significantly decreasing the method effectiveness. Vaginal misoprostol is more effective than oral administration, and has less side effects than sublingual or buccal. Some results are limited by the small numbers of participants on which they are based. Almost all trials were conducted in settings with good access to emergency services, which may limit the generalizability of these results.

Update on medication abortion

This article provides an overview of medication abortion in the United States 6 years after the approval of mifepristone (RU486; Mifeprex; Danco Laboratories, LLC, New York, NY) by the US Food and Drug Administration (FDA). The adoption of mifepristone is considered in the context of epidemiologic data on abortion, abortion access, and the safety of abortion. The risks of medication and aspiration abortion are discussed in the context of abortion-related mortality, recent experience with obstetric and gynecologic infection with Clostridium sordellii, and the limits of scientific knowledge on the incidence of this infection in women. Innovative protocols studied since FDA approval of mifepristone are presented, and implications for clinical practice are discussed.

Medical methods for first trimester abortion

BACKGROUND

Surgical abortion up to 63 days by vacuum aspiration or dilatation and curettage has been the method of choice since the 1960s. Medical abortion became an alternative method of first trimester pregnancy termination with the availability of prostaglandins in the early 1970s and anti-progesterones in the 1980s. The most widely researched drugs are prostaglandins (PGs) alone, mifepristone alone, methotrexate alone, mifepristone with prostaglandins and methotrexate with prostaglandins.

OBJECTIVES

To compare different medical methods for first trimester abortion.

SEARCH STRATEGY

The Cochrane Controlled Trials Register, MEDLINE and Popline were systematically searched. Reference lists of retrieved papers were also searched. Experts in WHO/HRP were contacted.

SELECTION CRITERIA

Types of studies. Randomised controlled trials comparing different medical methods (e.g. single drug, combination), ways of application, or different dose regimens, single or combined, for medical abortion, were considered. Trials were assessed and included if they had adequate concealment of allocation, randomisation procedure and follow-up. Women, pregnant in the first trimester, undergoing medical abortion were the participants. Different medical methods used for first trimester abortion, compared with each other or placebo were included. The outcomes sought include mortality, failure to achieve complete abortion, surgical evacuation (as emergency procedure, non-emergency procedure, or undefined), ongoing pregnancy at follow-up, time until passing of conceptus (> 3-6 hours), blood transfusion, blood loss (measured or clinically relevant drop in haemoglobin), days of bleeding, pain resulting from the procedure (reported by the women or measured by use of analgesics), additional uterotonics used, women's dissatisfaction with the procedure, nausea, vomiting, diarrhoea.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials for inclusion from the results of the search strategy described previously. The selection of trials for inclusion in the review was performed independently by two reviewers after employing the search strategy described previously. Trials under consideration were evaluated for appropriateness for inclusion and methodological quality without consideration of their results. A form was designed to facilitate the data extraction. Data were processed using Revman software.

MAIN RESULTS

Thirty-nine trials were included in the review. The effectiveness outcomes below refer to 'failure to achieve complete abortion' with the intended method unless otherwise stated. 1) Combined regimen mifepristone/prostaglandin: Mifepristone 600 mg compared to 200 mg shows similar effectiveness in achieving complete abortion (4 trials, RR 1.07, 95% CI 0.87 to 1.32). Misoprostol administered orally is less effective (more failures) than the vaginal route (RR 3.00, 95% CI 1.44 to 6.24) and may be associated with more frequent side effects such as nausea and diarrhoea. 2) Mifepristone alone is less effective compared to the combined regimen mifepristone/prostaglandin (RR 3.76 95% CI 2.30 to 6.15). 3) Similarly, the 5 trials included in the comparison of prostaglandin compared to the combined regimen reported in all but one higher effectiveness with the combined regime compared to prostaglandin. The results of these studies were not pooled but the RR of failure with prostaglandin alone is between 1.4 to 3.75 and the 95% confidence intervals indicate statistical significance. 4) In one trial comparing gemeprost 0.5 mg with misoprostol 800 mcg, misoprostol was more effective (failure with gemeprost: RR 2.86, 95% CI 1.14 to 7.18). 5) There was no difference when using split dose compared to single dose of prostaglandin. 6) Combined regimen methotrexate/prostaglandin: there was no statistically significant difference in failure to achieve complete abortion comparing methotrexate administered intramuscular to oral (RR 2.04, 95% CI 0.51 to 8.07). Similarly, early (day 3) vs late (day 5) administration of prostaglandin showed no significant of prostaglandin showed no significant difference (RR 0.72, 95% CI 0.36 to 1.43). One trial compared the effect of tamoxifen vs methotrexate and no statistically significant differences were observed in effectiveness between the groups.

REVIEWERS' CONCLUSIONS

Safe and effective medical abortion methods are available. Combined regimens are more effective than single agents. In the combined regimen, the dose of mifepristone can be lowered to 200 mg without significantly decreasing the method effectiveness. Misoprostol vaginally is more effective than orally. Some of the results are based on small studies only and therefore carry some uncertainty. Almost all trials were conducted in hospital settings with good access to support and emergency services. It is therefore not clear if the results are readily applicable to under-resourced settings where such services are lacking even if the agents used are available.