Androgen-dependent measurements of female genitalia in women with complete androgen insensitivity syndrome NS Crouch, Lina Michala, SM Creighton, GS Conway EGA Institute of Women’s Health, UCL Hospitals, London, UK Correspondence: Dr G Conway, EGA Institute of Women’s Health, UCL Hospitals, 250 Euston Road, London, NW1 2PG, UK. Email gerard.conway@uclh.nhs.uk Accepted 30 September 2010. Published Online 18 November 2010. Measurements of clitoral length and clitoral to urethral distance were made and analysed for a relationship in a group of 19 women with complete androgen insensitivity syndrome (CAIS) attending a specialist clinic for adult women with disorders of sexual development. These were compared with a control group of 50 women attending hospital for a gynaecological procedure. There was a positive correlation between clitoral length and clitoral to urethral distance for women with CAIS. In contrast, a negative correlation was seen between clitoral length and clitoral to urethral distance for women in the control group. Women with CAIS had a reduced mean clitoral length compared with controls (P = 0.001), but no difference was observed for the clitoral to urethral distance between the two groups (P = 0.116). Keywords Androgen, androgen insensitivity syndrome, clitoris, female genitalia, urethra. Please cite this paper as: Crouch N, Michala L, Creighton S, Conway G. Androgen-dependent measurements of female genitalia in women with complete androgen insensitivity syndrome. BJOG 2011;118:84–87. Introduction Development of the perineum is an androgen-mediated effect as evidenced by the larger anogenital distance (AGD) observed in men compared with women. The AGD, mea- suring from the base of the phallus to the centre of the anus has traditionally been used in animal studies 1 and is used as a way of assessing neonates and infants. 2 In animal studies, the AGD is an important indicator of fetal endo- crine effects 3 yet little is known regarding the significance of this measurement in humans. Phallic (penis or clitoris) length in humans is also androgen mediated. Individuals with disorders of sex development (DSD) may have various degrees of genital ambiguity. This has been attributed to a combination of fetal androgen produc- tion and the sensitivity of the genital tissues to androgen action. For example, women with congenital adrenal hyper- plasia are exposed to an excess of androgens in fetal life, and correspondingly have a greater AGD. However, it is not clear whether perineal development represents a continuum of androgen effect, whereby those with lower exposure to androgens have a shorter AGD than average. The effects of androgen excess can be explored in women with congenital adrenal hyperplasia but few escape feminising genital surgery in childhood so comparable mea- surements are limited. If there were a relationship between androgens and clitoral to urethral distance, women who have been exposed to very little or no androgens in fetal life, such as those with complete androgen insensitivity syn- drome (CAIS), would be expected to have the shortest dis- tance. It would also be reasonable to expect that women with CAIS would have a relatively short clitoral length but so far there is no documentation of this parameter in this condition. In contrast to measurements in men, scanty information is available in the literature regarding normal female genital measurements. Previous work from our unit has demonstrated the variety of genital appearance and mea- surements in women with no known genital ambiguity. 4 The aim of this study was to analyse the relationship between androgen-dependent measurements in a group of women with CAIS who were examined as part of their clin- ical care and then to compare these measurements with those from a control group of women with no known geni- tal ambiguity. 84 ª 2010 The Authors Journal compilation ª RCOG 2010 BJOG An International Journal of Obstetrics and Gynaecology DOI: 10.1111/j.1471-0528.2010.02778.x www.bjog.org Short communication