Spontaneous Midtrimester Uterine Rupture in a Primigravida with Endometriosis: A Rare Obstetric Emergency

Could Endometriosis Increase the Risk of Uterine Rupture in an Unscarred Uterus?

Spontaneous uterine rupture in an unscarred uterus is one of the rarest and most catastrophic obstetric emergencies. A recently published case report in the International Journal of Gynecology & Obstetrics highlights an unusual presentation of midtrimester uterine rupture in a primigravida with severe endometriosis and no prior uterine surgery, raising important questions about the impact of endometriosis on uterine integrity during pregnancy.

Key Clinical Takeaways

• Spontaneous uterine rupture can occur even in a primigravida with an unscarred uterus.

• Deep infiltrating endometriosis (DIE) may be an underrecognized risk factor.

• Acute abdominal pain in pregnancy should prompt consideration of uterine rupture, even in the second trimester.

• Early diagnosis and surgical intervention remain critical for maternal and neonatal survival.

• Women with severe endometriosis who conceive through assisted reproductive technologies (ART) may require enhanced antenatal surveillance.

Case Summary

A 33-year-old primigravid woman with primary infertility conceived following IVF-ET. She had no history of cesarean section, myomectomy, or other uterine surgery.

At 22+2 weeks of gestation, she developed sudden severe tearing lower abdominal pain shortly after defecation. Initial ultrasound demonstrated free intraperitoneal fluid, and she rapidly progressed to hemorrhagic shock.

Emergency laparotomy revealed:

• Approximately 1200 mL hemoperitoneum

• A 2-cm rupture in the right lateral uterine wall near the cornua

• Active bleeding beneath an intact serosal surface

• Extensive deep infiltrating endometriosis involving:

  • Uterine serosa

  • Bilateral adnexa

  • Pouch of Douglas

• Dense pelvic adhesions

An emergency cesarean delivery was performed. The infant weighed 430 g at birth and required prolonged neonatal intensive care. Maternal recovery was uneventful, and both mother and infant survived.

Why This Case Matters

Most uterine ruptures occur:

• During labor

• In women with previous cesarean scars

• Following uterine surgery

In contrast, spontaneous rupture of an unscarred uterus before fetal viability is exceptionally uncommon. The presence of extensive endometriosis in this patient provides further evidence supporting a possible association between severe endometriosis and compromised myometrial strength.

Endometriosis and Uterine Rupture: Understanding the Link

Several mechanisms have been proposed:

1. Chronic Inflammation

Endometriosis creates a persistent inflammatory environment characterized by cytokine release and tissue remodeling. Chronic inflammation may weaken myometrial architecture over time.

2. Fibrosis and Tissue Fragility

Deep infiltrating endometriosis often leads to fibrosis, scarring, and abnormal tissue repair. These changes may reduce the uterus’ ability to withstand progressive distension during pregnancy.

3. Decidualization of Endometriotic Lesions

Pregnancy-related hormonal changes can cause decidualization of ectopic endometrial tissue, potentially increasing local vascularity and tissue vulnerability.

4. Pelvic Adhesions

Severe adhesions may alter uterine biomechanics and create abnormal traction forces as the uterus enlarges.

5. Assisted Reproductive Technology

Emerging literature suggests that pregnancies achieved through IVF may carry unique obstetric risks in women with severe endometriosis, although definitive causality remains unproven.

Clinical Red Flags for Obstetricians

Consider uterine rupture when a pregnant patient presents with:

✅ Sudden severe abdominal pain

✅ Hemodynamic instability

✅ Unexplained hemoperitoneum

✅ Signs of hemorrhagic shock

✅ Fetal distress or sudden fetal compromise

✅ Known severe endometriosis or adenomyosis

Importantly, uterine rupture should remain in the differential diagnosis even when no prior uterine surgery has been performed.

Diagnostic Challenges

Midtrimester uterine rupture frequently masquerades as:

• Acute appendicitis

• Ovarian torsion

• Ruptured ovarian cyst

• Placental abruption

• Bowel pathology

• Renal colic

Ultrasound findings may be nonspecific and only reveal free fluid. Therefore, a high index of suspicion is essential.

Implications for Fertility and Endometriosis Specialists

This case reinforces the importance of:

Preconception Counseling

Women with severe endometriosis should be informed about rare but potentially serious pregnancy complications.

Risk Stratification

Patients with:

• Deep infiltrating endometriosis

• Extensive pelvic adhesions

• Adenomyosis

• Prior endometriosis surgery

• ART-conceived pregnancies

may benefit from individualized antenatal care plans.

Multidisciplinary Management

Collaboration between reproductive medicine specialists, maternal-fetal medicine experts, and gynecologic surgeons may improve outcomes in complex pregnancies.

Literature Review Highlights

Published reports suggest that spontaneous uterine rupture in primigravid women remains exceedingly rare. However, increasing numbers of case reports have identified associations with:

• Endometriosis

• Adenomyosis

• Congenital uterine anomalies

• Abnormal placentation

• Chronic pelvic inflammation

Although the absolute risk remains low, awareness among clinicians is critical because delayed diagnosis significantly increases maternal and fetal morbidity.

Practical Lessons for Daily Practice

1. Never dismiss severe acute abdominal pain in pregnancy.

2. Endometriosis may represent a clinically significant obstetric risk factor.

3. Hemoperitoneum in pregnancy warrants urgent evaluation.

4. Uterine rupture can occur before labor and before viability.

5. Early surgical intervention saves lives.

Bottom Line

Spontaneous midtrimester uterine rupture in an unscarred uterus is a rare but devastating obstetric emergency. This remarkable case highlights severe endometriosis as a potential contributor to uterine wall weakness and rupture during pregnancy. For obstetricians, fertility specialists, and maternal-fetal medicine practitioners, maintaining vigilance in pregnant patients with endometriosis may facilitate earlier diagnosis and improve maternal and neonatal outcomes.

Keywords

Spontaneous uterine rupture, unscarred uterus rupture, endometriosis pregnancy complications, deep infiltrating endometriosis, midtrimester uterine rupture, primigravida uterine rupture, acute abdomen in pregnancy, IVF pregnancy complications, maternal fetal medicine, obstetric emergency, hemoperitoneum pregnancy, uterine rupture case report, second trimester uterine rupture, high-risk pregnancy, OBGYN newsletter.

The newsletter is based on the recently published case report by Tianying Zhu and colleagues in the International Federation of Gynecology and Obstetrics, describing a 22-week spontaneous uterine rupture in a primigravida with severe endometriosis and no prior uterine surgery.

For the original article, see  International Journal of Gynecology & Obstetrics article page⁠.