The routine use of the supine position during the second stage of labor can be considered to be an intervention in the natural course of labor. This study aimed to establish whether the continuation of this intervention is justified. Nine randomized controlled trials and one cohort study were included. A meta-analysis indicated a higher rate of instrumental deliveries and episiotomies in the supine position. A lower estimated blood loss and lower rate of postpartum hemorrhage were found in the supine position, however it is not clear whether this is a real or only an observed difference. Heterogenous, non-pooled data showed that women experienced more severe pain in the supine position and had a preference for other birthing positions. Many methodological problems were identified in the studies and the appropriateness of a randomized controlled trial to study this subject is called into question. A cohort study is recommended as a more appropriate methodology, supplemented by a qualitative method to study women's experiences. Objective laboratory measurements are advised to examine the difference in blood loss. In conclusion, the results do not justify the continuation of the routine use of the supine position during the second stage of labor.