Ultrasound determination of the child’s sex is an additional study aimed at visualizing the external sexual characteristics of the fetus.
One of the advantages of ultrasound monitoring of pregnancy is the recognition of the sex of the unborn child at a fairly early stage. This will satisfy the curiosity of parents and give them the opportunity to better prepare for the birth of a baby (to purchase the necessary things).
On what ultrasound do they find out the sex of the child
On which ultrasound screening the sex of the child is determined. In total, three planned examinations are carried out during the gestational period at the following dates
- 10-14 weeks
- 20-22 weeks
- 30-32 weeks
An experienced sonologist working on a modern installation can determine the biological sex of the fetus at the first screening. But the accuracy of the results is about 60%. Often the position of the fetus excludes the visibility of the perineum. Then the 3D mode helps to determine the sex of the child on ultrasound for 20 weeks with 95% accuracy.
When is sex determination most accurate
It is almost unmistakable to find out by ultrasound who to wait for, a boy or a girl, after reaching the eighteenth obstetric week. The most reliable results are obtained at the time of 20-24 weeks. At the second screening, it is easier to determine the gender on ultrasound and fix it with a photo. If this is not possible due to the position of the child during the second ultrasound of pregnancy, it remains to determine the sex of the child at the stage of the third screening.
Stages of development
At the 13th week of fetal development, the formation of the genital organs from the genital tubercle begins.
In boys, the genital folds are transformed into a scrotum, a tubercle into a penis. In girls, the genitourinary folds and labial-scrotal tubercles are transformed into small and large labia, the genitourinary sulcus is transformed into the vestibule of the vagina.
Full formation ends at 20-22 weeks, then it is possible to identify the biological sex of the child with 99% accuracy.
Auxiliary signs of ultrasound determination of the child’s sex
On which ultrasound the sex of the child is determined by auxiliary signs. The genital tubercle is visible in the embryo at the beginning of the third month of gestation. Sex determination at this time is possible by calculating the angle of intersection of the lines of the mid-sagittal section through the genital tubercle and transverse to the skin of the sacrococcygeal region. The intersection angle of less than 30° means that a girl will be born, more than a boy. The accuracy of sex determination by this method for a period of 12 weeks was almost 99%.
Nuances of the study
There are cases in which it is not possible to determine the sex of the unborn child at the screening of the second or third trimester
- pelvic presentation of the fetus
- pose with strongly compressed knees
- accumulation of multiple umbilical cord loops in the perineum
- the butt of the fetus is tightly pressed to the pelvis
- lack of water
What is the percentage of errors when diagnosing gender on ultrasound
Can ultrasound make a mistake with the sex of the child? Yes, it is possible in some cases. When the examination is carried out on an outdated device, when the study is carried out on a small period of pregnancy. Therefore, it is important to choose well-equipped diagnostic centers, follow the recommendations of the leading obstetrician-gynecologist on compliance with screening deadlines.
The probability of an error when conducting a survey on a modern installation is only 0.02%.