BACKGROUND: Heterotopic pregnancy, defined as the coexistence of an intrauterine and an extrauterine pregnancy, is a rare but potentially life-threatening condition. While its incidence in assisted reproductive technology pregnancies is well documented, spontaneous heterotopic pregnancy remains exceedingly rare, particularly in sub-Saharan Africa. We present the case of a ruptured heterotopic pregnancy in a haemodynamically unstable patient, highlighting the diagnostic and management challenges in a resource-limited setting. CASE PRESENTATION: We present the case of a 34-year-old Ghanaian woman, Gravida 3 Para 1 (alive) + 1 spontaneous abortion, who presented to the Emergency Unit of the Obstetrics and Gynaecology Department at Komfo Anokye Teaching Hospital (KATH) with a 2-month history of amenorrhoea and a 1-day history of abdominal pain. Her vital signs on arrival indicated haemorrhagic shock (blood pressure 69/39 mmHg, heart rate 101 beats per minute). Bedside ultrasound revealed a live intrauterine gestation at 8 weeks with cardiac activity and a left adnexal mass with free fluid in the pelvis. She was resuscitated following the ATLS protocol and underwent emergency exploratory laparotomy under general anaesthesia. Intraoperatively, approximately 1.28 L of hemoperitoneum was drained, and a ruptured left isthmic ectopic pregnancy was identified and managed with total salpingectomy. The intrauterine pregnancy remained viable postoperatively. Progesterone supplementation (Depot Primolut injections and progesterone pessaries 400 mg twice daily) was commenced as institutional practice and continued until 16 weeks of gestation. Serial beta-hCG monitoring confirmed resolution of the ectopic component, with levels declining from 45,000 mIU/mL postoperatively to 12,500 mIU/mL by postoperative day 10. The intrauterine pregnancy progressed to 38 weeks of gestation, and the patient delivered a live female baby weighing 2.5 kg. CONCLUSIONS: This case underscores the importance of maintaining a high index of suspicion for heterotopic pregnancy in patients with acute abdominal symptoms, even when an intrauterine pregnancy has been confirmed. Rapid resuscitation, emergency surgical intervention with minimal uterine manipulation, and appropriate postoperative support are critical for maternal and intrauterine pregnancy survival, as demonstrated by the successful delivery at 38 weeks in this case.