Anogenital Distance in Term Newborns in Kumasi, Ghana

Estimation of Reference Values for External Genitalia Parameters in North Indian Preterm and Term Female Newborns

OBJECTIVES

To establish gestation-wise normative data of external genitalia measurements in North Indian term and preterm female newborns.

METHODS

In this cross-sectional descriptive study, institutionally-born female neonates between 28-42 wk gestation were consecutively enrolled between 24-72 h of life. Newborns with major congenital malformations, chromosomal anomalies, multifetal gestation and birth injuries were excluded. Data on various genital measurements were collected [Clitoral length (CL), clitoral width (CW), ano-clitoral distance (AGDAC), ano-fourchette distance (AGDAF) and anogenital ratio (AGR)].

RESULTS

One hundred ninety-eight of 508 neonates (39%) were preterm and 310 (61%) were term. Mean (± SD) CL and CW were 4.6 ± 1.8 mm and 3.9 ± 1.6 mm, respectively. Mean (± SD) values for AGDAF, AGDAC and AGR were 9.3 ± 1.8 mm, 30.2 ± 3.9 mm, and 0.31 ± 0.05, respectively. According to these results, term female newborns with CL more than 7 mm and/or CW more than 6 mm (95th centile) warrant evaluation for clitoromegaly. An anogenital ratio greater than 0.45 should be considered as a sign of virilization in a female neonate. Gestation-wise percentile charts for CL, CW, AGDAF, AGDAC and AGR were generated.

CONCLUSIONS

The percentile values defined in the study can serve as local normative data for accurate interpretation of genital measurements in North Indian female newborns and enable health care professionals for early identification of genital virilization.

Sex-specific ranges and ratios for anogenital distance among Thai full-term newborns

Introduction

Anogenital distance (AGD) is a marker of prenatal androgen exposure and a tool for assessment of differences of sex development. Data for AGD in newborns have been published, but these findings may not be applicable to Thai newborns.

Aim

To provide the sex-specific ranges for AGD in Thai full-term newborns.

Methods

A cross-sectional study was conducted in term newborns in Thailand, during 2016–2018. AGD was measured from anus to anterior base of penis (AGD_AP) and to perineoscrotal junction (AGD_AS) in males and from anus to clitoris (AGD_AC) and to posterior fourchette (AGD_AF) in females. AGD ratio is defined as AGD_AS divided by AGD_AP in males and AGD_AF divided by AGD_AC in females.

Results

A total of 364 newborns were studied (male 51.4%). The mean AGD_AS, AGD_AP and AGD ratio in males were 25.20 ± 4.80, 52.60 ± 6.90 and 0.48 ± 0.08 mm, respectively. The mean AGD_AF, AGD_AC, and AGD ratio in females were 16.50 ± 3.90, 42.60 ± 6.20 and 0.39 ± 0.08 mm, respectively. There were significant differences between AGD_AS and AGD_AF, AGD_AP and AGD_AC, and AGD ratio between males and females (p < 0.001). The AGD_AS, AGD_AP, AGD_AF, AGD_AC were correlated with birth weight and length, but AGD ratio showed no correlation.

Conclusion

The sex-specific ranges for AGD in Thai full-term newborns were determined. AGD ratio is a useful marker of prenatal androgen exposure since it differs between sexes, but constant between races and did not vary by body size.

Reference Values for and Correlation Analysis of the Anogenital Distance of Chinese Han Full-Term Singleton Neonates

BACKGROUND

Anogenital distance (AGD) is a biomarker used for the evaluation of fetal androgen action. The disruption of fetal androgen action can affect the development of the reproductive system and adversely affect future reproductive functions. However, AGD may differ by race. Currently, there is a lack of data regarding the evaluation of AGD in large Han Chinese samples.

OBJECTIVE

AGD for neonates in Shanghai, China, was measured, and relevant factors that influenced AGD were analyzed.

METHODS

The AGD of full-term singleton neonates was measured within 3 days of birth, and the results were grouped according to gestational age and body weight at birth. In addition, relevant factors that influenced AGD were investigated.

RESULTS

A total of 1,867 full-term singleton neonates were enrolled in this study. All the neonates were Han Chinese; among them, 986 were male, and 881 were female. Male AGD was 23.18 ± 3.17 mm, and female AGD was 11.65 ± 1.53 mm. Male AGD was 1.99 times longer than female AGD. With the increase in gestational age and body weight, AGD gradually increased. AGD was correlated with gestational age, body weight, and head circumference. The correlation between body weight at birth and AGD was highly significant.

CONCLUSION

This study, for the first time, reported AGD measurement data for Chinese Han neonates. The results indicated that AGD was correlated with gestational age, body weight, and head circumference. The correlation between body weight at birth and AGD was highly significant.

Clitoral sizes and anogenital distances in term newborns in Nigeria

BACKGROUND

Previous studies suggest significant ethnic and racial differences in clitoral sizes and anogenital distances in the newborn. This study aimed to document normative data on clitoral sizes and anogenital distances of apparently normal term female infants in Sagamu.

METHODS

The study was a multi-center, cross-sectional descriptive research carried out among 317 female term infants within the first 72 h of life. Interviewer-based questionnaire was applied to obtain sociodemographic data, pregnancy and birth history. A sliding digital caliper was used for measurement. Data analysis was with SPSS version 20.0.

RESULTS

The mean clitoral length was 6.7 ± 1.6 mm while the mean clitoral width was 5.6 ± 0.8 mm. The mean fourchette-clitoris distance, anus-clitoris distance and anus-fourchette distance were 21.9 ± 2.1 mm, 35.5 ± 2.5 mm and 17.0 ± 2.6 mm respectively. The anus-clitoris and anus-fourchette distances significantly correlated with the anthropometric parameters while the clitoral measurements did not.

CONCLUSION

The mean values recorded in this study were higher than observed in most previous studies. This simple, affordable and non-invasive evaluation could aid early diagnosis and treatment of female infants with potentially harmful conditions such as congenital adrenal hyperplasia.

In utero exposure to persistent and nonpersistent endocrine-disrupting chemicals and anogenital distance. A systematic review of epidemiological studies†

Anti-androgenic endocrine-disrupting chemicals (EDCs) can cross the placenta to modify early offspring sexual dimorphic markers. These changes are linked to anogenital distance (AGD), which is an androgen-sensitive anthropometric parameter used as a biomarker of perineal growth and caudal migration of the genital tubercle. This review aimed to summarize strength of evidence for associations of in utero exposure to EDCs with AGD and to identify gaps and limitations in the literature so as to inform future research. We performed an electronic search of English literature in September 2019 in medical literature analysis and retrieval system online (MEDLINE), Web of Science and Toxline. We included epidemiological studies that examined in utero exposure to persistent and nonpersistent EDCs and considered AGD in offspring as an outcome. Our review contained 16 investigations examining exposure to persistent EDCs (nine studies) and nonpersistent EDCs (seven studies). Some individual studies reported an inverse association between exposure to bisphenol A (BPA), dioxins, perfluoroalkyl substances, and organochlorides and AGD in both male and female offspring. Meta-analysis of three studies found a small reduction of AGD in female offspring exposed to BPA. The number of studies per chemical is small, and number of subjects examined is limited; so, replication of these results is needed. To achieve more specificity and better replication of results, future studies should establish the association of nonpersistent EDCs using multiple urine samples, evaluate the cumulative impact of exposure to a mixture of anti-androgenic chemicals, and offer adequate consideration of more maternal- and children-related confounding factors.