Multidosing Intramuscular Administration of Methotrexate in Interstitial Pregnancy With Very High Levels of β-hCG: A Case Report and Review of the Literature

Surgical Treatment Following Failed Medical Treatment of an Interstitial Pregnancy

Interstitial pregnancy (IP) is a type of ectopic pregnancy in which the embryo implants in the interstitial part of the Fallopian tube. It accounts for 2% of all ectopic pregnancies. Signs and symptoms appear later than the other forms of ectopic pregnancies because of its peculiar location. The gold standard for its diagnosis is transvaginal ultrasound. The treatment can be medical or surgical. Medical treatment is based on the systemic or local injection of methotrexate (MTX); a dose of mifepristone can be added with a reported 85–90% success rate. The surgical option is laparoscopic unilateral cornuostomy or unilateral salpingectomy. The therapeutic choice is based on symptoms, serum β-human chorionic gonadotropin (β-hCG) values, and sonographic features. Furthermore, the patient’s fertility perspectives should be considered. We report a case of IP in a Caucasian woman of 29 years old, with a previous salpingectomy for ectopic pregnancy medically treated by a double dose of intramuscular MTX 50 mg/m² combined with a single dose of leucovorin 15 mg and a single dose of mifepristone 600 mg orally. Medical therapy failed as suggested by the sudden onset of intense pelvic pain after 10 days. Because of the clinical symptoms and the sonographic suspicious of pregnancy rupture due to the modest amount of fluid in the pouch of Douglas, clinicians decided on an urgent unilateral laparoscopic salpingectomy. The hemoperitoneum was drained. The patient was discharged two days later and β-hCG serum levels became negative after 45 days. The advantages of fertility sparing should be weighted according to the patient’s reproductive perspectives. Appropriate counseling is therefore key in managing the treatment of interstitial pregnancy.

Conservative Treatment of Interstitial Ectopic Pregnancy with the Combination of Mifepristone and Methotrexate: Our Experience and Review of the Literature

Introduction

Interstitial pregnancy (IP) is an ectopic pregnancy (EP) located in the portion of the fallopian tube that penetrates the uterine muscular layer. Incidence increased in the last two decades with the widespread use of the assisted reproductive techniques. It is estimated in 1-6% of all the EPs, with a maternal mortality rate of 2.0-2.5%. Clinical presentation, gestational age at diagnosis, beta-human chorionic gonadotropin (β-hCG) levels, ultrasound features, and patient preference, should be considered to determine the best management: surgical, medical treatment, or close observation. We report two cases of IP successfully managed with systemic MTX and Mifepristone: in one case β-hCG was >10.000 mIU/mL and a vital embryo was present.

Materials and Methods

A literature search was carried out on MEDLINE, EMBASE, and PUBMED. We identified two cases of IP referred to the Institute for Maternal and Child Burlo Garofolo, Trieste. Data related to clinical presentation, β-hCG, and ultrasound scan at the moment of the diagnosis were recorded. In one of the cases, the β-hCG level was >10.000 mIU/mL, and a vital embryo was testified at an ultrasound scan. The patient was asymptomatic and she was treated using multidose systemic Methotrexate (MTX) combined with Mifepristone. In the second case, in the presence of a clinically stable patient with β − hCG > 10.000 mIU/mL, it was chosen that the administration of Mifepristone combined with a double dose of MTX. β-hCG levels and ultrasound examinations were performed weekly until a complete resolution of the IP.

Results

In the first case, β-hCG dropped down in 5 days and became undetachable in 30 days. In the second case, β-hCG became undetectable in 47 days. The first-line therapy in asymptomatic women could be addressed to a combined protocol, consisting of a systemic multidose MTX regimen with a single oral dose of Mifepristone.

Conclusions

Clinical management of IP remains a debated topic. In selected cases, a systemic multidose MTX regimen combined with a single oral dose of Mifepristone could be considered also in the presence of high serum β-hCG.