Ruptured rudimentary horn pregnancy masquerading as cesarean scar rupture in third trimester

Abstract

Pregnancy in the rudimentary horn of a unicornuate uterus is extremely rare and usual fate is rupture in the second trimester. We have reported this case due to rarity of rupture of rudimentary horn in the third trimester initially misdiagnosed as cesarean scar rupture. A 27-year-old G2P1 L1 with previous lower segment cesarean section presented at 33-week gestation with pain abdomen and syncopal attack with hemodynamic instability. The abdomen was distended and tender, uterine contour could not be made out, fetal parts were felt superficially, and fetal heart sound was absent. On vaginal examination, os was closed, bleeding was absent, and presenting part of the fetus was high up. A provisional diagnosis of cesarean scar rupture was made, and the patient was taken up for emergency laparotomy with simultaneous resuscitation. Intraoperatively, a left-sided ruptured rudimentary horn pregnancy and a unicornuate uterus with an intact lower segment transverse scar were found, a 1.5-kg macerated stillborn fetus was lying in the peritoneal cavity, and approximately two litres of hemoperitoneum was present. Excision of the rudimentary horn with ipsilateral salpingectomy was performed. High index of suspicion for uterine malformation is required for cases with a previous history of cesarean section for malpresentation. Moreover, catastrophic hemorrhage consequent to ruptured horn pregnancy can be avoided by excision of the rudimentary horn encountered incidentally.

Keywords

• Cesarean
• horn
• pregnancy
• rudimentary
• ruptured
• scar
• third