Does epidural versus combined spinal-epidural analgesia prolong labor and increase the risk of instrumental and cesarean delivery in nulliparous women?

1. Aneiros, F.
2. Vazquez, M.
3. Valiño, C.
4. Taboada, M.
5. Sabaté, S.
6. Otero, P.
7. Costa, J.
8. Carceller, J.
9. Vázquez, R.
10. Díaz-Vieito, M.
11. Rodríguez, A.
12. Alvarez, J.