Background: To describe a rare form of ectopic pregnancy and the clinical, ultrasound, and surgical approach to this unusual form.

Methods: We report a case of interstitial pregnancy discovered by ultrasound in a 29-year-old multiparous woman with no particular history. The diagnosis was based on a clinical examination and an ultrasound performed by suprapubic and endovaginal routes. The therapeutic intervention was performed by laparotomy.

Results: The diagnosis of interstitial pregnancy was established using ultrasound data and confirmed by a βHCG level of 10,000 mIU/mL. On transparietal ultrasound, the gestational sac appeared intrauterine and fundal. On transvaginal ultrasound, the uterus was empty and enlarged, with a well-distinguished endometrial line. We identified an ectopic gestational sac, presented as a mass on the right side of the uterine fundus, measuring 21 mm in internal diameter, corresponding to approximately nine weeks of amenorrhea. This mass was surrounded by a 5 mm thick myometrium. No intraperitoneal fluid effusion was observed. The patient was managed by laparotomy, which was successfully performed.

Conclusions:  Diagnosis of interstitial pregnancy is challenging, especially when relying solely on transparietal ultrasound, which is often insufficient to detect this pathology at an early stage. Prompt management is essential to prevent serious complications, such as uterine rupture. In the absence of immediate access to MRI in the emergency setting, transvaginal ultrasound, combined with βHCG measurement, constitutes a reliable method for early diagnosis and improved maternal prognosis.

Keywords: Ectopic pregnancy, HCG , laparotomy.

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Dr. Imane.Chanaa

Les Orangers Maternity and Reproductive Health Hospital, Rabat, Morocco