Spontaneous midtrimester uterine rupture in a primigravida with endometriosis: A case report and literature review.

Spontaneous uterine rupture in an unscarred uterus is a rare but life-threatening obstetric emergency, and endometriosis has increasingly been recognized as a potential risk factor. We report a 33-year-old primigravid woman with primary infertility who conceived via in vitro fertilization and embryo transfer, with no prior uterine surgery. At 22+2 weeks of gestation, she presented with sudden-onset, severe, tearing lower abdominal pain shortly after defecation. Bedside ultrasound revealed free intraperitoneal fluid, and she was diagnosed with hemorrhagic shock, prompting urgent transfer to our center. Emergency laparotomy identified approximately 1200 mL of hemoperitoneum and a 2-cm focal rupture in the right lateral uterine wall near the cornua, which exhibited active bleeding beneath an intact serosal layer. Extensive deep infiltrating endometriosis was identified intraoperatively, involving the uterine serosa, bilateral adnexa, and the pouch of Douglas, accompanied by dense pelvic adhesions. An emergency cesarean delivery was performed, resulting in the birth of a live male infant weighing 430 g. Apgar scores were 4, 6, and 8 at 1, 5, and 10 min, respectively. The patient recovered uneventfully and was discharged on postoperative Day 6. The neonate was admitted to the neonatal intensive care unit immediately after birth and discharged after a hospital stay of over 4 months, with a weight of 3700 g at discharge. This case underscores that endometriosis is an important but exceedingly rare risk factor for spontaneous midtrimester uterine rupture in primigravid women with an unscarred uterus. For women with endometriosis, particularly those conceiving through assisted reproductive technology, enhanced preconception counseling and individualized antenatal monitoring are warranted. Clinicians should include uterine rupture in the differential diagnosis of acute abdominal pain during pregnancy to ensure timely evaluation and intervention.