[Induction of labor in twin pregnancies compared to singleton pregnancies; risk factors for failure]

The aim of this study was to evaluate the modalities of induction of labour in twin pregnancies compared with singleton pregnancies and to identify risk factors for failure.

A retrospective population-based study was conducted at the Toulouse University Hospital to compare a cohort of diamniotic twin gestations (Twin A in vertex presentation), with induction of labour ≥36 weeks of gestation, between January 2007 and December 2012, to a singleton's cohort that were induced ≥36 weeks of gestation during the 2007 year. One singleton pregnancy was matched for each twin pregnancy with parity and gestational age.

One hundred and fifty-six twins pregnancies met the inclusion criteria for an induction of labor and were compared to 156 single pregnancies. The same and standard protocol of induction of labor was used for the two cohorts (intrauterine balloon catheter±dinoprostone/ocytocine). The cesarean section rate for failed labor induction (cesarean in latent phase) was similar in the 2 populations (14.7% for twin vs 13.5% for single; P=0.66). The factors associated to failed induction of labor in the total population were nulliparity (OR=1.49) and Bishop score<6 at the beginning of the induction (OR=2.83).

Twin did not appear as risk of failed induction. The protocol for induction of labor in singletons may be safely proposed to twin gestations.