Duration of second stage of labor and factors associated with prolonged second stage: A national population-based...

Prolonged second stage of labor could be associated with an increase in maternal and neonatal morbidity. However, in France, no consensual definition of prolonged 2nd stage of labor exists and therefore factors associated with prolonged second stage have not yet been studied. From national population-based data, we aimed at defining the prolonged 2nd stage of labor in France and identifying its associated factors for women with epidural.

From the French national perinatal survey of 2016, we included all women who reached 2nd stage of labor and delivered at term of a singleton infant in cephalic presentation. We studied the distribution of the duration of the 2nd stage according to parity and defined prolonged 2nd stage as the 90th percentile. Among women with epidural, factors associated with a prolonged 2nd stage of labor were then explored by univariate and multilevel multivariable analysis, to take the cluster effect into account. The proportional change of variance was estimated for each multivariate model.

Among the 8154 women included, 3574 were nulliparous and 4580 multiparous. Prolonged second stage was defined as a duration of more than 89.6 min and 30.6 min for nulliparous and multiparous women without epidural; and respectively 185.7 min and 120.1 min for women with epidural analgesia. The factors associated with prolonged 2nd stage of labor were respectively for nulliparous and multiparous women, macrosomia (aOR 1.74 [1.03-2.94] and ORa 2.52 [1.69-3.76]), prenatal preparation classes (aOR 1.47 [1.04-2.08] and aOR 1.56 [1.21-2.01]), a prolonged 1st stage (aOR 1.47 [1.14-1.87] and aOR 1.52 [1.19-1.95]) and delivery in a public maternity unit (aOR 2.68 [1.50-4.78] and aOR 3.12 [1.88-5.17]). Women's characteristics accounted for 3.4% of the variance and maternity organizational characteristics for 26.1%.

In France, prolonged 2nd stage of labor can be defined as a 2nd stage exceeding 3 h in nulliparous and 2 h in multiparous women with epidural analgesia. The identification of its associated factors allows determining a target population of women at risk of prolonged 2nd stage and improve their 2nd stage's management.