Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2026 Feb;45(2):241-249.
doi: 10.1002/jum.70051. Epub 2025 Sep 29.

Evaluating Male Fetal External Genital Morphology: A Systematic Review of Sonographic Techniques and Normative Values

Nikit Venishetty  1 , Akash Chauhan  2 , Ishant Goel  2 , Jonathan Balderrama  2 , Maral Demirjian  3 , Lorna Kwan  3 , Ilina D Pluym  4 , Renea Sturm  2
Affiliations
Review

Evaluating Male Fetal External Genital Morphology: A Systematic Review of Sonographic Techniques and Normative Values

Nikit Venishetty et al. J Ultrasound Med. 2026 Feb.

Abstract

Although commonly evaluated, fetal ultrasound assessments of penile length, width, and anogenital distance (AGD) lack standardized measurement techniques. This systematic review aimed to evaluate variability in measurement methods and generate normative growth curves for externally virilized genital development. Following PRISMA guidelines, PubMed, Google Scholar, and Web of Science were searched for studies reporting sonographic measurements of fetal penile length, width, or AGD by gestational age. Exclusion criteria included abnormal genitourinary development, intrauterine growth restriction, non-ultrasound imaging modalities, and non-English publications. Manuscripts were analyzed by a minimum of three reviewers. Data were standardized to mean dimensions and 95% confidence intervals by gestational week. Nine studies met inclusion criteria. Six measured penile length (scrotum to tip), four measured width (widest penile region), and three evaluated AGD (scrotum to anus). Resulting regression equations were y = 0.7862x - 8.4627 (length), y = 0.4209x - 3.1445 (width), and y = 1.0129x - 11.239 (AGD). Quality assessments revealed only 51.97 ± 21.5% of study parameters had a low risk of bias. The resultant growth curves provide a reference for normative development. Standardized assessment protocols and studies of anomalous development are needed to improve measurement consistency and assess the predictive value of these findings.

Keywords: anogenital distance; fetal ultrasound; genital development; penile length; penile width.

PubMed Disclaimer

Figures

Figure 1
Figure 1
PRISMA flow diagram of study selection for the systematic review on fetal genital measurements.
Figure 2
Figure 2
Ultrasound image of fetus at age 31 weeks. 1. Penile length was measured from the tip of the glans to the penoscrotal junction, aligned parallel to the penile axis. 2. Penile width was assessed at the widest point of the shaft. 3. Anogenital distance was measured from the center of the anus to the base of the scrotum.
Figure 3
Figure 3
Penile length across GA, combined analysis of data from six studies.
Figure 4
Figure 4
Penile width across GA, combined analysis of data from four studies.
Figure 5
Figure 5
Anogenital distance across GA, combined analysis of data from three studies.
See this image and copyright information in PMC

References

    1. Norton ME, Cheng Y, Chetty S, et al. Fetal anomalies consult series #4: genitourinary anomalies. Am J Obstet Gynecol 2021; 225:B2–B35. 10.1016/j.ajog.2021.06.009. - DOI - PMC - PubMed
    1. Van den Hof MC, Jain V, Nevo O. Clinical consensus no. 455: fetal sex determination and disclosure. J Obstet Gynaecol Can 2024; 46:102675. 10.1016/j.jogc.2024.102675. - DOI - PubMed
    1. The American College of Obstetricians and Gynecologists (ACOG) . Current ACOG Guidance. Washington D.C., USA: ACOG. https://www.acog.org/advocacy/policy-priorities/non-invasive-prenatal-te...; 2024.
    1. Danon D, Ben‐Shitrit G, Bardin R, Machiach R, Vardimon D, Meizner I. Reference values for fetal penile length and width from 22 to 36 gestational weeks. Prenat Diagn 2012; 32:829–832. 10.1002/pd.3913. - DOI - PubMed
    1. Akpinar F. Sonographic assessment of the fetal penile development. Fetal Pediatr Pathol 2016; 35:88–92. 10.3109/15513815.2015.1135494. - DOI - PubMed

LinkOut - more resources