Clitoral Length and Anogenital Ratio in Indian Newborn Girls.

Objective: To generate normative data on clitoris length, anogenital distance and anogenital ratio in Indian newborns.

Design: Cross-sectional study.

Setting: Neonatal unit of a tertiary care teaching hospital in Kolkata.

Participants: 378 female neonates, who were hemo-dynamically stable without critical illness or chromosomal anomaly, and without any vulval hematoma or genital abnormalities.

Interventions: Measurements were recorded using a digital vernier caliper between 24-72 hours. Infant was held in position by an assistant, while the investigator measured clitoral length by gently retracting the labia majora. Anogenital distance (centre of the anus to posterior convergence of the fourchette) and anogenital ratio (anogenital distance divided by the distance from centre of the anus to base of the clitoris) was also measured.

Main Outcome Measures: Gestational age- and birthweight-wise normative values of clitoral length, anogenital distance and anogenital ratios.

Results: Mean clitoral length was 3.1 (1.54) mm for the whole cohort while anogenital distance and anogenital ratio were 10.2 (2.78) mm and 0.34 (0.07) mm, respectively. The gestation age-wise percentile charts of clitoral length, anogenital distance and anogenital ratio have been generated. There was no correlation between clitoral length and gestational age, body length, head circumference and birth weight. Correlations were also weak for anogenital distance.

Conclusion: The normative values generated can serve as reference standard in the assessment of clitoromegaly, ambiguous genitalia, virilizing effects and suspected in utero androgen exposure.