OBJECTIVES: In agreement with national guidelines published in 2007, limiting duration of expulsive efforts to 30 minutes is a common obstetrical practice in France. In many other countries, there is no fixed limit for pushing duration. The objective of our work is to analyze mode of delivery and neonatal issues according to duration of expulsive efforts. PATIENTS AND METHODS: It is a secondary analysis of an observational prospective study, among low-risk primiparous women, in 138 French maternity units. According to duration of expulsive efforts, we determined proportions of spontaneous and instrumental vaginal deliveries. Then, we analyzed the risk of neonatal asphyxia (defined by pH