Floating fetal head in primiparas at term.

A total of 924 pelvimetries made for floating fetal head at term in primiparas was analyzed according to the pelvic parameters and outcomes. More android and platypelloid type pelves, and more OP position and Naegele's obliquities were found. Significant shortening of obstetrical conjugate. A-P diameter of actual inlet and reduced Mengert area of the inlet were the common characteristics in this series. One third of the patients required abdominal delivery, and half of the vaginal deliveries needed instrumental help.