Spontaneous Interstitial Heterotopic Pregnancy: Successful Pregnancy-Preserving Surgical Management

Heterotopic pregnancy, the simultaneous presence of an intrauterine and an ectopic gestation, is rare after spontaneous conception but may be life-threatening, as an intrauterine pregnancy can provide false reassurance during early assessment. Interstitial ectopic implantation is particularly hazardous because rupture can lead to severe hemorrhage. A 35-year-old gravida 3, para 2, presented at 9+4 weeks of gestation with mild lower abdominal discomfort and no vaginal bleeding. Ultrasound confirmed a viable intrauterine pregnancy but also free pelvic fluid, prompting short-interval reassessment. At 9+5 weeks, pain persisted with one episode of vomiting. Hemoglobin (Hb) fell from 127 g/L to 115 g/L, and intraperitoneal fluid increased. Transvaginal ultrasound showed a left interstitial mass adjacent to the uterine cavity, measuring 23.6 × 23.5 mm, raising suspicion for an interstitial ectopic pregnancy. Diagnostic laparoscopy revealed a ruptured left interstitial pregnancy with active bleeding and approximately 500 mL hemoperitoneum. Laparoscopic wedge resection with left salpingectomy was performed. The uterine defect was sutured with V-Loc, and total blood loss was estimated at 800 mL. Postoperative ultrasound confirmed continued viability of the intrauterine pregnancy, and histopathology confirmed ectopic pregnancy tissue. The patient was discharged on postoperative day seven with progesterone supplementation. Pregnancy continued uneventfully, and an elective primary cesarean section at 36+5 weeks delivered a healthy neonate with a well-healed uterine scar. Abdominal pain with free fluid warrants systematic adnexal evaluation even when an intrauterine pregnancy is confirmed. Pregnancy-preserving laparoscopy is feasible but requires close monitoring thereafter and planned delivery to avoid labor.