First Trimester Determination of Fetal Gender by Ultrasonographic Measurement of Anogenital Distance: A Cross-sectional Study

Background: In some patients with a family history of the gender-linked disease, determination of the fetal gender in the first trimester of pregnancy is of importance. In X-linked recessive inherited diseases, only the male embryos are involved, while in some conditions, such as congenital adrenal hyperplasia, female embryos are affected; hence early determination of fetal gender is important. Objective: The aim of the current study was to predict the gender of the fetus based on the accurate measurement of the fetal anogenital distance (AGD) by ultrasound in the first trimester. Materials and Methods: To determine the AGD and crown-rump length in this cross-sectional study, 316 women with singleton pregnancies were exposed to ultrasonography. The results were then compared with definitive gender of the embryos after birth. Results: The best cut-off for 11 wk to 11 wk, 6 days of pregnancy was 4.5 mm, for 12 wk to 12 wk, 6 days was 4.9 mm, and for 13 wk to 13 wk, 6 days was 4.8 mm. Conclusion: AGD is helpful as an ultrasonographic marker that can determine fetal gender in the first trimester, especially after 12 wks. Key words: Sonography, Gender, Female, Male, Pregnancy, First trimester