Reference values for fetal penile length and width from 22 to 36 gestational weeks

Area of Science:

• Prenatal diagnosis
• Fetal development
• Medical imaging

Background:

• Current fetal penile growth references rely on length, with inconsistent measurement techniques.
• Penile width measurement is proposed as a complementary evaluation tool.

Purpose of the Study:

• To establish normative reference ranges for fetal penile length and width.
• To correlate these measurements with gestational age and estimated fetal weight.

Main Methods:

• Prospective cross-sectional study of 100 male fetuses (22-36 weeks gestation).
• Ultrasound measurements of penile length (tip to base) and width (widest point).
• Calculation of 5th and 95th percentile values for each gestational week.

Main Results:

• Strong correlation found between gestational age and both penile length (R²=0.606) and width (R²=0.683).
• Estimated fetal weight percentile independently influenced penile dimensions.
• High interobserver reliability for both length (0.939) and width (0.909) measurements.

Conclusions:

• Normative reference values for fetal penile length and width (22-36 weeks gestation) are provided.
• These measurements are correlated with gestational age and estimated fetal weight percentile.
• The established reference ranges can assist in evaluating suspected cases of micropenis.