Uterus didelphys is a congenital abnormality characterised by double uteri, double cervices and a double or single vagina that affects 0.3% to 11% of the general female population. A 23-year-old woman, gravida 3 para 3003, with uterus didelphys, acquired an iatrogenic interuterine septal defect during an otherwise routine primary caesarean delivery for fetal malpresentation. The defect was repaired but noted to have dehisced during her second pregnancy. A repeat caesarean section was performed due to fetal malpresentation after an unsuccessful external cephalic version. The dehisced defect was left unrepaired. During her third pregnancy, the placenta implanted in the right uterus, but the fetus migrated to the left uterus at approximately 28 weeks gestation. The umbilical cord traversed the interuterine septal defect. With the fetus in the vertex presentation at term gestation, the patient underwent a vaginal birth after two previous caesarean deliveries without any major perinatal complications.