Rupture of a rudimentary horn pregnancy with a combined intrauterine pregnancy. A case report.

In the first reported case of a rudimentary horn pregnancy coexistent with an intrauterine pregnancy, the patient presented at 19 weeks' gestation with acute abdominal distress. A ruptured left rudimentary horn pregnancy was found at laparotomy. The rupture was repaired. Preterm labor ensued 24 hours later, with resultant delivery of the second twin from the right cornu despite aggressive tocolysis.