Severity of prematurity risk in spontaneous and in vitro fertilization twins: does conception mode serve as a risk factor?

Because assisted reproductive technology (ART) contributes to world-wide increases in twin pregnancies, we retrospectively evaluated whether preterm twin gestations after ART are at higher risk for delivery at earlier gestational ages compared with naturally conceived twins. The evaluation of 204 dichorial twin pregnancies, 102 after natural conception and 102 after ART, matched for maternal age, demonstrated comparable severity of prematurity risk in both groups.