Predictive value and reference ranges of anogenital distance for determining fetal gender in the first trimester: A retrospective cohort study

Imaging in fetal genital anomalies

Genital anomalies are a heterogeneous group of congenital pathologies that have become increasingly relevant since the Chicago Consensus of 2005. Their postnatal diagnosis has developed significantly in the last two decades, while prenatal diagnosis seems to be underdeveloped, with few protocols available, fragmented scientific literature, and low diagnostic rates. This review aims to examine the current status of this subspecialty from the perspective of prenatal imaging. Indications for the evaluation of fetal genitalia can be divided into medical and non-medical reasons. Medical reasons include sex-linked disorders, detection of other anomalies, relevant family history, or multiple pregnancy. Non-medical reasons include parental request for sex disclosure. Disclosure of fetal sex may be associated with ethical, legal, and medical issues. The main imaging technology used is 2D ultrasound, although there are other complementary techniques such as 3D, MRI, or Color Doppler. Regarding working methodology, several authors have drawn attention to the lack of standardized protocols and guidelines. Most guidelines tend to limit their recommendations to study indications and ethical issues. Technical proposals, measurements, or working methods have not yet been standardized. Fetal sex determination is usually divided into early and late gestation. Early gestation is based on the sagittal sign. Late gestation is based on direct visualization. There are several measurements to describe male and female genitalia, such as penile length, bilabial diameter, or scrotal diameter. Prenatal diagnosis of genital pathologies presents some particularities such as the wide spectrum of phenotypes, the high frequency of associated deformities, or the time of diagnosis. Some of the most frequent pathologies are ambiguous genitalia, fetal sex discordance, hypospadias, micropenis, clitoromegaly, ovarian cysts, hydro(metro)colpos, and cloacal anomalies. Higher-quality studies and direction from scientific societies through the implementation of clinical guidelines are needed.

Relationship among anogenital distance, adrenal gland volume, and penile length and width at 22-36 weeks of pregnancy

OBJECTIVES

The subject of current work was to determine the relationship of fetal ultrasonographic biomarkers, including anogenital distance (AGD), adrenal gland volume, and penile length and width in mothers with male fetuses at 22-36 weeks of gestation for the assessment of the effect of fetal adrenal gland producing androgens on the male anogenital structures that are exposed to androgen effects as anogenital region and penis.

METHODS

This study is a prospective cross-sectional study conducted in our hospital's outpatient perinatal care unit. One hundred and seventy pregnant women with a male fetus aged 22-36 weeks of gestation were included in the study. The fetal adrenal gland length, width, and depth for the calculation of adrenal volume, AGD, and penile length and width were measured for each participant. The Pearson coefficients were calculated to assess the correlation among these parameters.

RESULTS

The adrenal gland volume had a meaningful, positive moderate relationship with both the AGD (r=0.60) and penile length and width (r=0.57 and r=0.59, respectively; p<0.001). The AGD had a positive, strong correlation with the penile length and width (r=0.74 and r=0.76, respectively; p<0.001).

CONCLUSIONS

The fetal adrenal gland as one of the androgen sources of the fetus is an influencer of the development of the anogenital and penile region. The findings of the current study support that the adrenal gland considerably affects the masculinization of male fetuses, since there were remarkable correlations among the AGD, adrenal gland volume, and penile length and width.