What is the biparietal diameter of a boy at 20 weeks?

What is the biparietal diameter of a fetus at 20 weeks? Is it a boy? The fetal biparietal diameter is mainly used during pregnancy to check whether the baby is developing healthily. Generally, the fetal biparietal diameter cannot distinguish between male and female. The gender of the fetus can be determined through amniocentesis, B-ultrasound, etc. Let’s take a look at it together below.

In fact, it is unreasonable to use fetal biparietal diameter to determine fetal gender. However, there is a folk saying that fetal biparietal diameter can determine fetal gender.

First of all, if the parents are tall and strong, then for boys and girls regardless of pregnancy, the bipartite ratio will basically exceed 2.1 in the late pregnancy (after 30 weeks), and it does not rule out that it will exceed 2 in the early stage. It is not easy for such parents to use this method to distinguish between men and women.

On the contrary, if parents are not tall, they are not big. At the beginning of the 24th week of pregnancy, the fetal biparietal diameter minus the fetal femoral length = more than 1.7. From then on, the fetal biparietal diameter-fetal femur length began to increase slowly with each B-ultrasound. If the difference is 1.7 at 24 weeks, 2 at 28 weeks, and 2.1 or more after 30 weeks, then the baby born to this type of mother is likely to be a boy, and the probability of conceiving a boy increases by 80%.

In fact, using fetal biparietal diameter to determine whether the fetus is a male or female is not scientific enough and has no basis.

At this stage, among the methods that obstetricians and gynecologists can use to determine the gender of the fetus, the most useful and reliable methods are:

1. Ultrasonic scanner

Ultrasound is a sound wave frequency. Reports so far show that it has no adverse effects on the fetus, so it is widely used in the field of obstetrics and gynecology. When using ultrasound to determine the gender of the fetus, the accuracy for male babies is more than 95%, while the accuracy for female babies is only about 85%.

2. Amniocentesis

Amniocentesis is mainly used to diagnose whether the fetus has sex chromosomes or neural tube defects, and is usually performed between 16 and 20 weeks of pregnancy. Because the sex chromosomes of the fetus can be known, the sex of the fetus can also be known. The accuracy is 99%, but there is a 1% chance of miscarriage. Therefore, doctors do not agree to perform amniocentesis just to determine the gender of the fetus.

3. Plush collection technique

Also known as "plush sampling", it is usually done between 8 and 10 weeks of pregnancy. The main purpose is the same as amniocentesis, which is to confirm whether the sex chromosomes of the fetus are normal, but many people use it to confirm the gender of the fetus, with an accuracy of 98%.