External genital proportions in prepubertal girls: a morphometric reference for female genitoplasty

An understanding of normal genital anatomy is essential for a successful surgical approach and outcome in feminizing genitoplasty. We sought to establish genital standards in female children through external genital measurements taken from the end of the neonatal period until the beginning of adolescence.

This prospective study included 205 females who were anesthetized for surgery for various diagnoses between January 2007 and March 2008. Patient age ranged from 1 month to 10 years. Patients were divided into 4 age groups-1 to 12, 13 to 24, 25 to 60 and 61 to 120 months. Information on patient age, height, weight and, for patients younger than 1 year, head circumference was retrieved from patient charts. Measurements of clitoris length, clitoris width, labia majora length, left and right labia minora length and width, and perineal distance were recorded.

Specific equations were generated using these values to estimate the expected external genital structure dimensions in girls. Length of labia majora vs age, length of labia majora vs body weight, perineal distance vs body weight, clitoral width vs body weight and clitoral length vs age reference percentile curves were prepared.

The equations and percentile curves generated can be used as a guide in prospective feminizing genitoplasty. Furthermore, patients and their families can be informed regarding the variability of external genitalia dimensions. This information should ensure a healthier appreciation of the postoperative genitalia by patients and their families.