TY - CHAP M1 - Book, Section TI - Vaginal Delivery A1 - Cunningham, F. Gary A1 - Leveno, Kenneth J. A1 - Bloom, Steven L. A1 - Dashe, Jodi S. A1 - Hoffman, Barbara L. A1 - Casey, Brian M. A1 - Spong, Catherine Y. PY - 2018 T2 - Williams Obstetrics, 25e AB - As soon as the head appears at the vulva the physician should be ready to restrain its progress. He should hold his hand in such a manner as to be able to bring it immediately into action, for in many instances the resistance of the vulva is unexpectedly overcome, and a single pain may be sufficient to push the head suddenly through it with a resulting perineal tear.—J. Whitridge Williams (1903) SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - obgyn.mhmedical.com/content.aspx?aid=1160775997 ER -