Incidence and outcomes of uterine rupture in women with unscarred, preterm or prelabour uteri: data from the international network of obstetric survey systems.

Uterine rupture in preterm, prelabour or unscarred uteri are extremely uncommon but were associated with severe maternal and perinatal outcome. We found a mix of risk factors in unscarred uteri, most preterm uterine ruptures occurred in caesarean-scarred uteri and most prelabour uterine ruptures in 'otherwise' scarred uteri. This study may increase awareness among clinicians and raise suspicion of the possibility of uterine rupture under these less expected conditions.