Related Experiment Video
Updated: May 22, 2026

Anogenital Distance and Perineal Measurements of the Pelvic Organ Prolapse (POP) Quantification System
Published on: September 20, 2018
Perineal body length among different racial groups in the first stage of labor
Pai-Jong Stacy Tsai1, Ian A Oyama, Mark Hiraoka
1Department of Obstetrics, Gynecology, and Women's Health, John A. Burns School of Medicine, University of Hawaii, 1319 Punahou St, Suite 824, Honolulu, HI 96826, USA. paijong@hawaii.edu
Objective:
Anatomic differences among racial groups may contribute to observed differences in the occurrence of severe perineal lacerations at the time of vaginal delivery. The purpose of this study was to identify differences in perineal body length between racial groups.
Methods:
Perineal body length was measured in primigravid women aged 18 to 45 years who were admitted in labor. Women were classified into 1 of 6 racial groups: White, Filipino, Japanese, Chinese, Native Hawaiian, or Micronesian. The primary outcome, perineal body length, was compared using analysis of variance.
Results:
A total of 200 women were recruited. There were no significant differences in perineal body length (P = 0.42) and severe perineal lacerations (P = 0.82) between the different racial groups. The mean (SD) perineal body length of women who had a severe laceration was 3.9 (0.5) versus 3.9 (0.6) cm in women who did not have a severe laceration (P= 0.98).
Conclusion:
Perineal body length does not seem to differ among the different racial groups studied and therefore an unlikely cause of racial variation in rates of severe perineal lacerations.
Related Concept Videos
Muscles of the Pelvic Floor and Perineum
Perineal Layer
The perineum is a diamond-shaped area below the pelvic diaphragm, divided into an anterior urogenital triangle that contains the external genitals and a posterior anal triangle housing the anus. The urogenital...
Local Anesthetics: Clinical Application as Epidural Anesthesia
Since epidural anesthetics can be infused through an epidural catheter, all types of drugs, including short-acting ones, can be administered. Chloroprocaine and lidocaine are examples of short and long-duration anesthetics, respectively. Bupivacaine...
Assessment of the Rectum and Anus
Rectal Inspection
Begin by inspecting the perianal and anal areas for color, texture, rashes,...
Uterus and Cervix
The uterus is securely anchored within the pelvic cavity by paired broad ligaments on either side. It is further stabilized by three pairs of...
