There is a substantial chance of getting a false-negative diagnosis if the ultrasound imaging for fetal gender identification has been performed in the first trimester of pregnancy. Seeing the internal pelvic structure of the fetus, including the uterus and ovary, is also used to help identify the fetal gender. With technological advances, seeing the vulva, clitoris, and labia are taken to indicate a female fetus, whereas seeing the scrotum, penis, testicles, and raphe indicate a male fetus. In the early studies conducted on the use of ultrasound results for identifying the fetal gender, a male fetus was demonstrated by the presence of a scrotum and a penis, and a female fetus by the absence of these organs. In the second and third trimesters of pregnancy, ultrasound imaging scans the genital anatomy of the fetus to identify its gender. If the examination of the midline sagittal view of the genital area shows a caudal notch, the fetus is female, and if it shows a cranial notch, then the fetus is male. A downward tubercle indicates a female fetus and an upward tubercle a male fetus. The fetal gender can be identified even in the first trimester of pregnancy from the 11 th-week onward through observing the direction of the genital tubercle and sagittal sign.

Occasionally, CVS is difficult to perform, posing a 1%–5% threat of pregnancy loss. Accurate prenatal identification is currently only possible through invasive procedures and chorionic villus sampling (CVS). The early prenatal identification of fetal gender is of great importance in the management of pregnancy in families at risk for certain inherited diseases.

12 week sonogram