A prospective double-blinded, randomized, placebo-controlled trial on the use of letrozole pretreatment with misoprostol for second-trimester medical abortion

Effect of misoprostol with and without letrozole on the induction of abortion for women with first-trimester missed abortion

OBJECTIVE

To determine whether addition of letrozole to a misoprostol-based abortion regimen can increase the rate of complete abortion.

METHODS

The randomized, placebo-controlled, double-blind trial enrolled women with missed abortion in the first trimester of pregnancy attending Sadooghi Hospital, Isfahan, Iran, from 2016 to 2018. The women were randomly assigned to the study group, which received 10 mg of letrozole daily for 3 days, followed by two doses of 800 μg of vaginal misoprostol at a 4-hour interval, or the control group, which received a placebo, followed by the same dose of misoprostol. Sonography was performed to check the abortion status.

RESULTS

In total, 120 women completed the study: 60 in the misoprostol plus letrozole group, and 60 in the misoprostol only group. Complete abortion was documented for 93 (77.5%) women: 48 (80.0%) in the misoprostol plus letrozole group and 45 (75.0%) in the misoprostol only group (P=0.80). The mean duration of induction in the misoprostol plus letrozole and misoprostol only groups was 7.35 ± 3.54 hours and 8.2 ± 3.8 4hours, respectively (P=0.21).

CONCLUSION

Administration of misoprostol alone was found to be as effective as the administration of misoprostol plus letrozole for first-trimester missed abortion.

The efficacy of letrozole supplementation for medical abortion: a meta-analysis of randomized controlled trials

INTRODUCTION

The efficacy of letrozole supplementation for medical abortion remains controversial. We conduct a systematic review and meta-analysis to explore the influence of letrozole supplementation for medical abortion.

METHODS

We searched PubMed, Embase, Web of Science, EBSCO, and Cochrane Library databases through October 2018 for randomized controlled trials (RCTs) assessing the effect of letrozole supplementation for medical abortion. This meta-analysis is performed using the random-effect model.

RESULTS

Six RCTs involving 555 patients are included in the meta-analysis. Overall, compared with control group for pregnant women, letrozole supplementation shows significantly increased complete abortion (RR = 1.38; 95% CI = 1.07-1.78; p = .01), and decreased estradiol (std. MD = -2.86; 95% CI = -4.45 to -1.27; p = .0004), but has no remarkable effect on induction-abortion time (std. MD = -1.03; 95% CI = -2.99-0.93; p = .30), progesterone (std. MD = 0.02; 95% CI = -0.30-0.34; p = .89), vaginal hemorrhage (std. MD = 1.84; 95% CI = 0.05-70.90; p = .74), nausea and vomiting (std. MD = 073; 95% CI = 0.44-1.21; p = .22).

CONCLUSIONS

Letrozole supplementation provides benefits to medical abortion in pregnant women.

Letrozole vs. Placebo Pretreatment in the Medical Management of First Trimester Missed Miscarriage: a Randomized Controlled Trial

INTRODUCTION

Misoprostol is used for the medical management of miscarriage as it is more effective in the early stages of pregnancy. Letrozole has an anti-estrogen effect and is used for the pretreatment of miscarriage with misoprostol.

AIM

The aim of this study was compare the efficacy and safety of letrozole with placebo pretreatment in the medical management of first trimester missed miscarriage.

DESIGN

This was a prospective randomized case-control study.

PATIENTS AND METHODS

Four hundred and thirty-eight women were randomly divided into two groups of 219; the placebo group received placebo tablets twice daily for 3 days, followed by 800 micrograms of misoprostol vaginally on the fourth day of enrolment, while the letrozole group received letrozole 10 mg twice daily for three days followed by 800 micrograms misoprostol administered vaginally. Symptoms and side effects were recorded, and the women advised to return to hospital if they experienced severe pain or bleeding or intolerable side effects and to report to hospital for a check-up one week after misoprostol administration. Ultrasound was done seven days after misoprostol administration to monitor outcomes. Surgical evacuation was carried out if medical management failed.

RESULTS

There were significant differences between the two groups, with better outcomes found for the letrozole group in terms of rates of complete miscarriage, onset of vaginal bleeding, and interval between induction and onset of expulsion (p < 0.001). A higher rate of nausea and vomiting was reported for the letrozole group (p = 0.002). Differences between groups with regard to pre- and post-termination hemoglobin levels, fever, severe pain and severe bleeding needing evacuation were not statistically significant.

CONCLUSION

Adding letrozole to misoprostol improves the success rate and decreases the interval between induction and expulsion in cases of first trimester miscarriage; however, nausea and vomiting is higher with letrozole.

The effect of 7 days of letrozole pretreatment combined with misoprostol on the expression of progesterone receptor and apoptotic factors of placental and decidual tissues from first-trimester abortion: a randomized controlled trial

OBJECTIVE

To evaluate if letrozole-induced suppression of estradiol reduces progesterone receptor expression and apoptosis in the first-trimester placenta.

STUDY DESIGN

We performed a double-blinded, randomized, placebo-controlled trial. We randomized 20 women requesting first-trimester abortion with gestation up to 63 days to receive either letrozole 10 mg daily or placebo pretreatment for 7 days before administrating 400 mcg of vaginal misoprostol followed by suction abortion. We collected the placental and decidual tissues on which we performed immunohistochemical staining for progesterone receptor and apoptotic markers (active caspase 3, caspase 3, Bcl2, CD95, fas ligand) and determined H-scores of each based on the intensities of staining. We performed terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling (TUNEL) assay for apoptosis in the samples of four women to confirm the findings from apoptotic markers.

RESULTS

We excluded one woman in the letrozole group from the analysis because she had passage of abortus after taking letrozole, leaving 19 women (9 in the letrozole group, 10 in the placebo group) for analysis. There was no significant difference in the H-scorings of progesterone receptor and apoptotic markers, as well as proportion of apoptotic cells on TUNEL assay between the two groups. The H-scores for the progesterone receptor were 8.17 ± 2.67 (mean ± SD) in the letrozole group and 9.01 ± 2.82 in the placebo group (p=0.36).

CONCLUSION

We did not detect a difference in the expression of progesterone receptor and apoptotic markers in placental and decidual tissues after letrozole pretreatment for 7 days in first-trimester abortion.

IMPLICATIONS

We did not confirm the hypothesis that letrozole reduces progesterone receptor expression and induces apoptosis in the first-trimester placenta. Further studies are required to allow better understanding of the mechanism by which estrogen suppression following the use of letrozole can lead to improved abortion rate in the first trimester.

The effectiveness of using misoprostol with and without letrozole for successful medical abortion: A randomized placebo-controlled clinical trial

Background:

In developing countries it is important to the exploration of available and safe regimens for medical abortion. The present study was designed to assess the effect of letrozole compared to placebo pretreatment followed by sublingual misoprostol for therapeutic abortion in eligible women with gestational age less than 17 weeks.

Materials and Methods:

In this randomized control trail, 130 women eligible for legal abortions were randomly divided into two groups of case and controls. Cases received daily oral dose of 10 mg letrozole 10 mg letrozole for three days followed by sublingual misoprostol. Controls received daily oral dose of placebo followed by sublingual misoprostol. The dose of misoprostol was administrated according to ACOG guidelines based on patients’ gestational age. The rate of complete abortion, induction-of-abortion time, and side-effects were assessed as main outcomes.

Results:

Complete abortion was observed in 46 (76.7%) letrozole group and 26 (42.6%) controls (P < 0.0001). Also, in 14 subjects of letrozole group and 35 subjects in placebo group, the placenta was not delivered during follow-up and curettage was performed. The mean interval induction-to-abortion was 5.1 h in letrozole group and 8.9 h in control (P < 0.0001). The cumulative rates of the induction-of-abortion time were a significant difference between the two groups (P < 0.0001). The incidence and severity of side-effects was comparable for the two groups (P = 0.9).

Conclusion:

Letrozole could be a quite beneficial adjuvant to misoprostol for induction of complete abortion in those who are candidates for legal medical abortion.

Effect of letrozole on uterine artery Doppler flow indices prior to first-trimester termination of pregnancy: a randomized controlled trial

OBJECTIVE

We previously demonstrated that a sequential regimen of letrozole and misoprostol resulted in a marked reduction in the serum estradiol concentration and in a higher efficacy of first-trimester termination of pregnancy than misoprostol alone. The aim of this study was to evaluate the effect of letrozole on uterine artery Doppler flow indices during early pregnancy.

METHODS

This was a randomized controlled trial. Thirty women requesting termination of pregnancy up to 63 days' gestation were randomized into two groups: a letrozole group receiving 10 mg of letrozole, daily, for 3 days, and a control group receiving a placebo for 3 days. Serum estradiol, progesterone and human chorionic gonadotropin (hCG) concentrations were measured before drug administration and then daily for 6 days. Ultrasound scanning for fetal viability and measurement of the pulsatility (PI) and resistance (RI) indices of the uterine arteries was performed before drug administration, and then on day 3 and day 7 after starting letrozole or placebo. All pregnancies were terminated by surgical evacuation on day 7 or day 8.

RESULTS

Uterine artery PI and RI decreased significantly in the letrozole group, but not in the control group. Serum estradiol concentrations were significantly lower in the letrozole group than in the control group from day 2 onwards. Serum progesterone and hCG concentrations were comparable for the two groups throughout the 7 days. There were significantly more women in the letrozole group with vaginal bleeding.

CONCLUSION

We have demonstrated that the use of letrozole in the first trimester of pregnancy suppresses serum estradiol levels but results in an increase in blood flow to the uterus. Further studies should be carried out to elucidate the mechanism of letrozole pretreatment in medical abortion.