Population-specific reference values for clitoral dimensions and anogenital distance among healthy term female neonates in Ethiopia: a Cross-Sectional Study

Abstract Background Careful examination of the external genitalia at birth is an essential component of newborn assessment and may provide the first indication of disorders of sex development (DSD), including congenital adrenal hyperplasia (CAH), a potentially life-threatening endocrine disorder if unrecognized. In many low-resource settings, where newborn screening programs and timely hormonal or genetic investigations are limited, clinical assessment remains a critical tool for identifying infants who require further evaluation. Objective measurements of clitoral size and anogenital distance (AGD) provide simple, non-invasive markers of external genital development and prenatal androgen exposure. However, population-specific reference data for these measurements are lacking in Ethiopia. This study aimed to establish normative reference values for clitoral dimensions and AGD among healthy term female neonates in Ethiopia and to evaluate their relationship with neonatal anthropometric characteristics. Methods A hospital-based cross-sectional study was conducted among 284 healthy term female neonates delivered at Saint Paul’s Hospital Millennium Medical College, Addis Ababa, Ethiopia, from July to August 2021. Clitoral length (CL), clitoral width (CW), anus–fourchette distance (AFD), and anus–clitoris distance (ACD) were measured within the first 72 hours of life using calibrated digital vernier calipers by trained examiners. Neonatal anthropometric characteristics, including birth weight, length, and head circumference, were recorded. Reference intervals were calculated using the mean ± 2 standard deviations (SD). Pearson correlation analysis was performed to evaluate associations between genital measurements and neonatal anthropometric parameters. Results The mean gestational age of participants was 38.95 ± 1.21 weeks. The mean (± SD) CL, CW, AFD, and ACD were 9.27 ± 1.60 mm, 4.11 ± 0.97 mm, 10.60 ± 1.58 mm, and 31.51 ± 4.11 mm, respectively. The corresponding reference intervals were 6.06–12.47 mm for CL, 2.17–6.05 mm for CW, 7.44–13.76 mm for AFD, and 23.29–39.73 mm for ACD. ACD showed significant positive correlations with birth weight (r = 0.218, p < 0.001) and birth length (r = 0.222, p < 0.001). No significant associations were observed between clitoral dimensions and neonatal anthropometric characteristics. Conclusions This study establishes the first population-specific reference intervals and gestational age-specific reference curves for clitoral dimensions and AGD among healthy term female neonates in Ethiopia. These findings provide clinically relevant tools to support newborn genital assessment and early recognition of infants who may require evaluation for DSD, particularly in settings where biochemical screening and genetic testing are not routinely available. Further multicenter studies across diverse Ethiopian populations are needed to validate and refine these reference standards.