Secondary Abdominal Pregnancy in a Mare: Successful Surgical Management of a Rare Uterine Rupture

Uterine rupture in mares is rare, but when it occurs, survival often depends on rapid diagnosis and surgical intervention. Most cases are associated with dystocia, traumatic fetal manipulation, or uterine torsion¹. 

What made this case extraordinary was not only the rupture itself, but the development of secondary abdominal pregnancy, a condition in which the fetus escapes from the uterus and remains within the abdominal cavity¹. 

Even more remarkable: the mare survived. 

A Dead Fetus Floating in the Abdomen 

After failing to foal by day 350 of gestation, an Arabian mare underwent repeat ultrasonographic evaluation. 

Findings included¹: 

• An empty involuted uterus  

• Free peritoneal fluid  

• A dead fetus freely floating in the abdominal cavity  

• No evidence of active dystocia  

The fetus was no longer enclosed within fetal membranes. 

Despite the severity of the condition, the mare remained surprisingly stable clinically. 

Surgical Intervention 

A ventral midline laparotomy was performed under general anesthesia. 

During surgery, clinicians identified¹: 

• A near-term dead fetus free within the abdomen  

• Placental remnants within the peritoneal cavity  

• Diffuse fibrous and fibrinous adhesions  

• A full-thickness 10 cm linear tear in the ventral uterine body  

The uterine rupture was repaired using a double inverting suture pattern with absorbable polyglactin 910. 

The abdomen was lavaged extensively with 25 liters of lactated Ringer’s solution to reduce contamination risk. 

Why Septic Peritonitis Did Not Develop 

Postpartum uterine rupture is commonly followed by septic peritonitis due to bacterial contamination of the abdomen³. 

Interestingly, this mare avoided that outcome. 

The likely reason was cervical closure. Because the cervix remained closed, communication between the uterus and external environment was limited, reducing bacterial contamination. 

This may have been the key factor that preserved the mare’s prognosis. 

Adhesions and Abdominal Complications 

The surgeons also encountered significant adhesions involving: 

• Colon serosa  

• Cecum  

• Falciform ligament  

These likely developed because the fetus and placental tissues had remained free within the abdominal cavity for several days. 

Adhesions were carefully dissected and cauterized, and sodium carboxymethylcellulose was applied to reduce future adhesion formation⁴. 

Postoperative Management 

The mare received: 

• Procaine penicillin and dihydrostreptomycin  

• Gentamicin  

• Flunixin meglumine  

• Oxytocin  

Remarkably, recovery was uneventful, and no postoperative complications developed. 

Importantly, surgeons preserved the uterus instead of performing ovariohysterectomy, maintaining the mare’s future reproductive potential. 

Why This Case Matters 

This case highlights several valuable clinical points: 

Uterine rupture can occur without dramatic systemic illness 

The mare remained relatively stable despite a catastrophic lesion. 

Mild torsion can have delayed consequences 

The earlier uterine torsion likely initiated the chain of events leading to rupture. 

Early surgery changes prognosis 

Prompt laparotomy prevented worsening peritonitis and secondary abdominal complications. 

Fertility may still be preserved 

Careful uterine repair avoided the need for ovariohysterectomy. 

Conclusion 

This rare case of secondary abdominal pregnancy following uterine rupture demonstrates both the dangers of late-gestation uterine compromise and the value of timely surgical management. 

Even in severe reproductive emergencies, successful outcomes are possible when diagnosis, surgery, and postoperative care are performed promptly and aggressively. 

References  

1. Palmieri V, Catone G, Conte A, Di Palma T, Liguori P, Izzo I, Vullo C. Near-Term Extrauterine Pregnancy Secondary To Uterine Rupture In A Mare. Journal of Equine Veterinary Science. 2026 May 22:105943. https://www.sciencedirect.com/science/article/pii/S0737080626001784  

2. MURUGAN, M., KUMAR, K.S., NAPOLEAN, R.E., GOPIKRISHNAN, D., SELVARAJU, M., RAVIKUMAR, K., PALANISAMY, M. and DHARMACEELAN, S., AN UNUSUAL CASE OF UTERINE TORSION AND ITS MANAGEMENT BY LAPAROHYSTEROTOMY IN A KATHIAWARI MARE. Haryana Veterinarian, 62(2), pp.148-149. https://www.luvas.edu.in/haryana-veterinarian/download/dec-2023/32.pdf  

3. Diekstall M, Rohde C, Rijkenhuizen AB. Post‐partum uterine rupture: standing repair in three mares using a laparoscopic technique. Equine Veterinary Education. 2020 Jun;32(6):319-24. https://doi.org/10.1111/eve.13001  

4. Hay WP, Mueller PE, Harmon B, Amoroso L. One percent sodium carboxymethylcellulose prevents experimentally induced abdominal adhesions in horses. Veterinary Surgery. 2001 May;30(3):223-7. https://doi.org/10.1053/jvet.2001.17849