Evaluation of Letrozole and Methotrexate in the Management of Ectopic Pregnancy - A Randomized Clinical Trial Study.

The mean age of patients in the letrozole group was 5.1 ± 31.8 years, and that in the methotrexate group was 6.2 ± 32.9 years. In terms of basic and clinical characteristics such as age, employment status, educational status, body mass index, number of pregnancies, abortion, EP location, and its mass, no significant difference was found between the two groups ( P > 0.05) [ Table 1 ]. Basic and clinical characteristics differences between the two groups Mean±SD or n (%). EP=Ectopic pregnancy, SD=Standard deviation, BMI=Body mass index On the first day of treatment, the β-hCG level was not significantly different between the two groups ( P > 0.05). In addition, although a significant decrease in β-hCG levels was found in each of the two groups over time ( P 0.05) [ Table 2 and Figure 2 ]. Beta human chorionic gonadotropin levels in the letrozole group compared with the methotrexate group Comparison of biochemical and hematologic parameters in the follow-up times between the two groups a The significance level of the independent sample t -test comparing the variables mean between the two groups in each of the follow-up times, b The significance level obtained from the repeat measure ANOVA comparing the mean β-hCG over time in each of the two groups, c The significance level of the paired sample t -test to compare the variables mean on the 7 th day compared to the 1 th day in each of the two groups. β-hCG = β-human chorionic gonadotropin, AST=Aspartate transaminase, ALT=Alanine transaminase, Hb=Hemoglobin, SCr=Serum creatinine, AMH=Anti-mullerian hormone, CI=Confidence interval Furthermore, the mean of AST, ALT, Hb, and SCr on the first and seventh days of treatment did not have any significant difference between the two groups ( P > 0.05). Also, by passing time, no significant changes were reported in each group ( P > 0.05) [ Table 2 ]. The methotrexate group exhibited lower AMH levels compared to the letrozole group at the third month of treatment. However, it is important to emphasize that the observed decrease in AMH levels was not found between the two groups ( P = 0.425). Also, the decrease of AMH in each of the two groups was insignificant ( P > 0.05) [ Table 2 ]. Finally, there was no significant difference in successful treatment in 14 cases (70%) of the letrozole group with 17 cases (85%) of the methotrexate group ( P = 0.282). Although side effects (including fatigue, acute abdominal pain, nausea, other) were more in the methotrexate group than in the letrozole group, this difference was not significant ( P > 0.05) [ Table 3 ]. Treatment outcome and side effects of patients in the two groups *Successful treatment was defined as a >15% reduction in β-hCG levels between days 4 and 7, **Other side effects such as vertigo, headache, joint’s pain. β-hCG=Beta human chorionic gonadotropin

The present study contributes to the growing body of evidence supporting the potential use of letrozole as a medical treatment for EP. It offers an effective, safe, and less invasive alternative to surgical approaches, with comparable resolution rates and fewer adverse effects. Further research, with larger sample sizes, wider beta ranges, and rigorous controls, is needed to validate the efficacy of letrozole and elucidate its impact on long-term fertility and reproductive outcomes. The potential for letrozole to transform the management of EP is promising, offering new horizons in the field of reproductive healthcare. This study approved by Ethics Committee of Isfahan University of Medical Sciences (Approval code: IR.MUI.MED.REC.1400.559) and was registered in WWW.IRCT.org with the clinical trial code (IRCT code: IRCT20170828035961N2) There are no conflicts of interest.

The results of this study indicated no significant difference in the effects of letrozole and methotrexate on hematological and biochemical parameters such as AST, ALT, Hb, SCr, and β-hCG. Also, subsequent monitoring of β-hCG levels over time revealed that both treatment groups demonstrated a similar rate of reduction in β-hCG levels. This finding underscores the comparable efficacy of letrozole and methotrexate in reducing β-hCG levels, a critical marker in the management of EP. Furthermore, the current study showed that the resolution rate for EP using a 5 mg dose of letrozole was 70%, while the resolution rate (successful treatment) of using 50 mg/m 2 of body surface area of methotrexate was 85%, although this difference was not significant. It may be stated that the administration of 5 mg/day of letrozole resulted in a considerably safe and high success rate of EP termination without imposing any serious side effects. These findings are broadly consistent with a recent study by Mitwally et al ., which reported a human resolution rate of 86% for EP using 5 mg/day of letrozole.[ 7 ] The minor discrepancy in outcomes between these studies may be attributed to the relatively small sample sizes in both investigations. Also, these results align with those of an experimental study by Tiboni et al ., where rats treated with letrozole (equivalent to a daily human dose of 2.5 mg) exhibited similar findings, emphasizing the potential of letrozole as an effective treatment for EP.[ 14 ] The superior safety profile of letrozole in comparison to methotrexate, coupled with its successful application in managing various gynecological conditions, provides impetus for further exploration of its role as a medical treatment for EP.[ 7 15 ] The mechanism of action of aromatase inhibitors (AIs), including letrozole, centers on the inhibition of androstenedione and testosterone conversion to estrone and estradiol, resulting in the suppression of estrogen production.[ 16 ] The rationale for using AIs in EP treatment stems from the established role of estrogens in implantation and embryonic development.[ 17 ] Evidence suggests that aromatase inhibition may reduce progesterone’s influence in early pregnancy support, potentially due to downregulation of progesterone receptors.[ 7 ] Animal models have provided insights into the impact of AIs on pregnancy. Such studies have shown disturbances in early embryo development and the inability to sustain pregnancy when AIs are administered.[ 18 19 ] Additionally, several studies, including a meta-analysis encompassing 555 women, have demonstrated the high efficacy of AIs when combined with misoprostol in abortion treatment.[ 20 ] Clinical cases, such as that described by Kochhar et al ., have provided further support for letrozole’s potential in treating EP. In a case involving a 28-year-old woman with chronic tubal pregnancy, letrozole treatment yielded positive outcomes, as evidenced by a reduction in β-hCG levels and favorable transvaginal ultrasound results.[ 21 ] An integral component of our study involved the evaluation of AMH levels at the third month of treatment. In this study, intriguingly, the methotrexate group exhibited lower AMH levels compared to the letrozole group at this post-treatment time point. However, the observed decrease in AMH levels did not achieve statistical significance. This nonsignificant difference prompts further exploration into the clinical implications of both letrozole and methotrexate treatments on long-term fertility and reproductive potential in patients treated for EP. Comparing the median for EP mass between two groups was not meaningfully different. In a nonrandomized study of 42 women with tubal EP (tEP), Mitwally et al . divided participants into three treatment groups. They reported complete resolution of EP in 86% of patients across both primary study groups—a finding consistent with our results. Notably, β-hCG levels declined more rapidly with letrozole than with methotrexate. Furthermore, letrozole showed no discernible impact on hematologic, hepatic, or ovarian reserve parameters (including Hb, platelet counts, liver enzymes, and AMH). In contrast, methotrexate significantly altered these markers, with observed reductions in AMH levels.[ 7 22 ] In a study by Nabil El-Sayed et al ., involving 50 women diagnosed with tEP, both letrozole and methotrexate treatments demonstrated equal efficacy, with success rates of 86%. Furthermore, β-hCG levels declined more rapidly in women treated with letrozole.[ 23 ] The present study has several limitations, including the small sample size and β-hCG levels <2000 mIU/mL. However, the superior safety profile of letrozole compared with chemotherapeutic agents such as methotrexate should encourage examining letrozole as a promising medical treatment for EP. Furthermore, letrozole may be a safer alternative compared with the surgical approach for managing early pregnancy loss, particularly in patients with whom surgery and anesthesia are contraindicated, and even for pregnancy termination when it is medically indicated and ethically appropriate.

This was a double-blind randomized clinical trial study. Participants include all women with EP who referred to Hospitals’ Obstetrics and Gynecology Departments affiliation and supervision of Isfahan University of Medical Sciences from 2022 to 2024. Inclusion criteria encompassed patients aged 18–40 years with proven EP, no surgical indication (β-hCG >5000 mIU/mL, ectopic mass >4 cm, embryonic heart activity, and unstable vital signs), and no contraindications to methotrexate treatment including breastfeeding, immunodeficiency state, hematology abnormalities, active pulmonary disease, alcoholism, and important hepatic or renal diseases. Exclusion criteria included unstable vital signs or symptoms of internal bleeding, an increase in liver enzymes (including aspartate aminotransferase [AST] and Alanine aminotransferase [ALT]) or serum creatinine (SCr), or a decrease in hemoglobin (Hb) or platelets (PLT) during the study and occurrence of severe drug side effects such as severe sensitivity. EP was suspected in pregnant women presenting with abdominal or vaginal bleeding, or both, in conjunction with a positive pregnancy test. Diagnostic confirmation involved the use of ultrasound to detect ectopic sacs or fetuses, or the persistence of elevated β-hCG levels with absence of intrauterine gestational sac. After obtaining the ethics code and receiving written consent from eligible women, a total of 40 women were randomly selected. Their demographic and laboratory data, including anti-mullerian hormone (AMH), β-hCG, PLT, SCr, Hb, AST, and ALT, were recorded. Participants were randomly divided into two groups using Random allocation software, one receiving methotrexate ( n = 20) and the other letrozole made by Iran Hormon Pharmaceutical Company ( n = 20) [ Figure 1 ]. Consort flowchart of patients Methotrexate recipients received a single dose of 50 mg/m 2 of body surface via intramuscular injection. Letrozole recipients were prescribed 5 mg to be taken daily for 10 consecutive days.[ 9 ] To comply with blinding conditions, two drugs, letrozole and methotrexate, are placed in coded packages by the pharmacy manager and delivered to the researcher, who is unaware of the type of each. Also, the person recording the clinical and basic information of the patients as well as the statistical analyst will not be aware of the type of intervention. The patients were hospitalized for 48 h after receiving the medicine, and after that, if their vital signs were stable, there were no problems, and they were easily accessible to the hospital; they were followed up on an outpatient basis. Patients were visited at certain intervals in the hospital for examination and test checks. In the intervals between the visits, the condition of the patients was checked by phone call. β-hCG levels were assessed on the first, fourth, seventh, and fourteenth days of treatment. Additionally, AST, ALT, PLT, SCr, and Hb were evaluated on the first and seventh days of treatment. Successful of treatment was defined as a >15% reduction in β-hCG levels between days 4 and 7.[ 11 12 13 ] To assess the impact on fertility, AMH levels were measured at the third month of treatment and compared to initial levels at the time of EP diagnosis. Also, side effects of both treatments were assessed until the treatment was completed. Letrozole side effects included hot flashes, edema, headache, dizziness, fatigue, nausea, constipation, joint pain, shortness of breath, and cough. For methotrexate, common side effects encompassed skin issues (hair loss, acne, photosensitivity), hematological complications (aplastic anemia, thrombocytopenia), liver disturbances (elevated liver enzymes, cirrhosis), diarrhea, vomiting, and acute kidney injury. The statistical analysis was conducted using SPSS version 26.0 (SPSS Inc., Chicago.IL, USA). The data were presented as mean ± standard deviation or n (%). The independent sample t -test was used to compare the mean quantitative variables between the two groups at each time. Furthermore, repeated measure ANOVA was employed to assess the changes in the β-hCG level between the two groups by passing time. The paired t -test was used to compare the mean of quantitative variables on the seventh day of treatment compared to the first day of treatment in each group. Additionally, the Chi-square test was used to compare the frequency distribution of qualitative variables between the two groups. A significance level of less than 0.05 was considered a statistically significant difference.