Letrozole Versus Methotrexate for Management of Undisturbed Ectopic Pregnancy

Ectopic pregnancy (EP) was defined as the implantation of fertilized ovum anywhere other than the endometrial uterine cavity and accounts for 1-2% of all pregnancies , but its prevalence after assisted reproduction trials was found to be higher. Tubal EP (TEP) is the commonest and is associated with a high risk of rupture leading to extensive bleeding and complicated surgery,so it represents asignificant threat to maternal life . Management of Ectopic pregnancy is still a source of debate where surgical management; salpingotomy or salpingectomy is curative but insufficient removal of the ectopic tissue may occur with salpingotomy causing persistent trophoblast tisseue . Other sites of ectopic pregnancy including, cervix, myometrium, ovary, abdominal cavity.

Heterotopic pregnancy refers to coexistence of an intrauterine pregnancy with an ectopic pregnancy in any these locations.

The classic clinical triad of ectopic pregnancy is pain, amenorrhea, and vaginal bleeding; unfortunately, only about 50% of patients present with all 3 symptoms. About 40-50% of patients with an ectopic pregnancy present with vaginal bleeding, 50% have a palpable adnexal mass, and 75% may have abdominal tenderness.The availability of transvaginal ultrasonography (TVU) and serum βhuman chorionic gonadotropin (βhCG) assay allowed early diagnosis of EP and paved the way for medical treatment of EP, but within certain conditions .

A standard treatment option for many patients of ectopic pregnancy , Single- and multi-dose systemic methotrexate (MTX) protocols are used most commonly, with no difference in success rate. Given its simplicity and low complication rate, the singledose protocol is used more widely throughout the world . The single dose regimen consists of an intramuscular injection (IM) of MTX (50 mg/m2 of body surface area), with administration of additional doses at weekly intervals in patients with an inadequate response. Repeated injections are permitted every 7 days for up to 3 doses second dose is needed in 20 % or more of patients, while less than 1 % of patients require 3 or more doses. The single dose regimen is associated with fewer side effects as compared to other regimens . Methotrexate is a folic acid antagonist that inhibits the enzyme dihydrofolate reductase, which converts folic acid to tetrahydrofolate, a cofactor needed in DNA and RNA synthesis . By inhibiting dihydrofolate reductase, methotrexate interrupts trophoblast proliferation and induces abortion. Methotrexate is as effective as salpingostomy for ectopic pregnancy and does not appear to affect future fertility .However, no dose of MTX is immune against side effects even small doses . Multiple studies documented the safety and efficacy of single-dose methotrexate (SD-MTX) as a medical treatment for EP that in carefully selected cases might be an effective alternative to surgery . However, the efficacy of SD-MTX is recently questionable and multiple studies tried to evaluate the efficacy of two-dose versus SD-MTX for the medical management of EP. Third-generation aromatase inhibitors such as letrozole are well established in clinical use for suppressing estrogen production in women with breast cancer. Their safety, high tolerability, low cost, and associated minimal adverse effects have all been established over several decades of clinical use .This group of aromatase inhibitors including, letrozole, has been shown to Successfully block estrogen production in reproductive age.

In the absence of estrogen priming, progesterone may not exert its physiological functions due to a negative effect on progesterone receptors. It was hypothesized that by inhibiting the estrogen synthetase (the aromatase enzyme), the progesterone would not exert its physiological function in maintaining pregnancy, including ectopic pregnancyPrevious study evaluate the effective role of adding letrozole to methotrexate in management of tubal ectopic pregnancy. our study will aim to compare between the effect of methotrexate versus letrozoe in management of ectopic pregnancy.

Inclusion criteria

• Confirmed ectopic pregnancy on trans vaginal ultrasound
• Age between 20 and 35 years
• A β-hCG levels < 3000 Iu/ L
• The average diameter of the adnexal mass ≤3.5 cm
• Stable hemodynamic condition

Exclusion criteria

• Presence of fetal heart pulsation
• Heterotopic pregnancy
• Presence of significant abdominal pain
• history of allergic reactions to MTX or letrozole
• Any known liver disorder or abnormal liver enzyme levels (AST or ALT )
• Any known renal disorder or impaired renal function tests (abnormal creatinine)