Stretched penile length at birth: a systematic review

BACKGROUND

Micropenis is an endocrinological condition that is habitually observed at birth. Diagnosis is made by measuring the stretched penile length, a method established 80 years ago. Discrepancies in the normative data from recent studies raise the need for a current revision of the methodology.

OBJECTIVES

The aims of this systematic review were to compare the different normative data of SPL at birth, to examine the methodological aspects of the technique and to evaluate the independent variables that may be involved.

METHODS

Searches were performed using MEDLINE, EMBASE, Scielo, the Cochrane Library and Web of Science. A combination of the relevant medical terms, keywords and word variants for "stretched penile length", "penile length", "penile size", "newborn" and "birth" were used. Eligibility criteria included normative studies that used the stretched penile length (SPL) measurement on a population of healthy, full-term newborns during the first month of life. The outcomes studied included characteristics of the studies, methodological aspects and independent variables.

RESULTS

We identified 49 studies comprising 21,399 children. Significant discrepancies are observed between the different studies. Methodological aspects seem to be consistent and similar. The main independent variables appear to be ethnic group and gestational age. Main limitations were the absence of studies of entire world regions such as Europe or South America, and the heterogeneity of the ethnic background that complicates the analysis.

CONCLUSIONS

It seems advisable to suggest the creation of customized reference charts for each specific population instead of resorting to the classic cut-off points.

Open-legs axial plane: A standardized methodology and reference values for fetal genital biometry in mid-trimester ultrasound

BACKGROUND

Evaluation of the external genitalia is an important part of prenatal ultrasound. However, there is no standardized methodology that includes biometric measurements and normative data to be able to carry out this evaluation.

OBJECTIVE

To develop a standardized methodology for fetal genital biometry and obtain reference values for use in mid-trimester ultrasound.

STUDY DESIGN

A prospective cross-sectional study was used. 273 male and 253 female fetuses of normal, singleton pregnancies at 18 to 22 weeks were included. Measurements of fetal penis length, penile width and transverse scrotal diameter in male fetuses and bilabial diameter in female fetuses were performed by transabdominal ultrasound. Reference values were calculated for each gestational week.

RESULTS

Realization of the open-legs axial plane is described as a working methodology. Normative data for penile length, penile width, transverse scrotal diameter and bilabial diameter are defined, including mean, minimum and maximum values, range, and 5th, 10th, 90th and 95th percentiles.

CONCLUSIONS

We have provided a standardized methodology using the open-legs axial plane, which would integrate the main measurements. In addition with the normative data constructed from their use, we hope to be able to improve the external genitalia assessment and diagnosis of genital anomalies in mid-trimester ultrasound.