The head and chin are eased out of the vaginal opening to prevent the mother's tissues from tearing. Such maneouvers aid the mother in the delivery of her child. Once the baby's head has emerged, the body rotates to allow the shoulders to come out one at a time. The rest of the body then usually slides out quickly. In rare circumstances forceps or an episiotomy may be need.
Birth then enters the third stage, the delivery of the afterbirth .
A Practical Guide. Report of a Technical Working Group, World Health Organisation, Department of Reproductive Health and Research, 1999.