Interstitial ectopic pregnancy successfully treated with methotrexate

Abstract

An ectopic pregnancy (EP) occurs when the fertilised ovum implants outside the endometrial cavity. An EP has an incidence of 1%, with the majority occurring in the fallopian tube. It has a maternal mortality of 0.2 per 1000, with about two-thirds of these deaths associated with substandard care. An interstitial pregnancy occurs when the EP implants in the interstitial part of the fallopian tube. An interstitial ectopic pregnancy (IEP) shows few early clinical symptoms, hence it is associated with serious or fatal bleeding and a mortality rate up to 2.5%. With the advent of transvaginal ultrasound scan (TV USS), correlated with serum beta human chorionic gonadotropin (BHCG) assay, earlier diagnosis of an EP can be established. An EP is often diagnosed in women who are trying to conceive; therefore, the prognosis of future fertility is one of the main concerns associated with this diagnosis. Management can be surgical, expectant or medical with methotrexate (MTX). However, the best approach is tailored to the woman’s individual case. The authors present the case of a primigravida woman presenting with abdominal pain and vaginal bleeding at 6 weeks gestation following assisted reproduction. Her BHCG showed a suboptimal rise. Her TV USS showed no evidence of an intrauterine pregnancy. There was no evidence of an adnexal mass or free fluid. As her BHCG remained static, she underwent a diagnostic laparoscopy. A right sided IEP was identified. Due to the high risk of bleeding requiring transfusion or hysterectomy and her desire to preserve her fertility, she received medical management with MTX. Indeed, research has shown that women successfully managed expectantly achieve better reproductive outcomes, with the shortest time to achieve a subsequent intrauterine pregnancy. This case acts as a cautionary reminder of the challenges associated with identifying an IEP on TV USS. A high index of clinical suspicion is required to prevent maternal morbidity and mortality.