How many times should I do ultrasound during pregnancy?

Women need to do many prenatal checkups during pregnancy, because this is the only way to determine the health of the fetus in the belly. B-ultrasound is a common way of prenatal checkups, and the price of B-ultrasound is relatively expensive, and it is less harmful to women's bodies. Generally, B-ultrasound is done when the first pregnancy check is done. When the fetus is about one month old, it can be seen. So how many B-ultrasounds should be done during pregnancy?

During pregnancy, approximately 5 to 7 ultrasound scans are usually performed. The first time is at 6-8 weeks of pregnancy, to determine whether it is an intrauterine pregnancy and to rule out ectopic pregnancy; the second time is at 12-14 weeks, NT color ultrasound, to check fetal chromosomal abnormalities by the thickness of the fetal nuchal translucency, combined with mid-term Down syndrome screening, it can screen 60%-75% of chromosomal abnormalities; the third time is 20-24 weeks of pregnancy, color ultrasound for major fetal abnormalities, that is, four-dimensional color ultrasound; the fourth time is a follow-up color ultrasound at 30-32 weeks, to check whether there are any abnormalities in the fetal structure and whether the size is consistent; the fifth time is at 36-37 weeks, to evaluate the size of the fetus, amniotic fluid, and placenta through B-ultrasound, and preliminarily determine the mode of delivery. If it is a high-risk pregnancy, the number of B-ultrasound examinations should be increased. The above 5-7 B-ultrasounds are essential and are an important part of prenatal examination. There is no need to worry about the impact of B-ultrasound on the fetus.

According to the date of the last menstrual period, the expectant mother should have her first color ultrasound examination around 6 to 8 weeks of pregnancy. This ultrasound scan has two main purposes:

The first is to determine whether the position of the gestational sac is correct, because some pregnant women may have ectopic pregnancy, and ectopic pregnancy requires early intervention, otherwise it is very dangerous. So in the first color ultrasound, we first determine whether the gestational sac is inside or outside the uterine cavity.

The second purpose is to see whether the fetus develops normally in the early stages of pregnancy. The doctor will check the gestational age based on the size of the fetal heart rate and embryo bud. Because some women have irregular menstruation, if we calculate the time of pregnancy based solely on menstruation, there will be a relatively large error.

In general, the first color ultrasound is to determine the position of the gestational sac on the one hand, and to observe the size of the fetus to verify the gestational age on the other.

Second time: 12-14 weeks

The color ultrasound examination performed between 12-14 weeks of pregnancy has a special name, called "NT color ultrasound".

NT refers to the thickness of the fetal nuchal translucency. This is a very special structure. As the fetus grows, this structure will gradually disappear, so it must be checked and measured between 12 and 14 weeks of pregnancy.

The thicker the NT, the higher the risk that the child will carry abnormal genetic material. Therefore, if the NT value of the fetus is relatively large, we may need to conduct corresponding examinations during subsequent prenatal examinations to determine whether there is any problem with the fetus.

In addition to observing the NT thickness, we also need to measure the size of the fetal head and other diameters, and combine them with the previous B-ultrasound examination to comprehensively determine whether the gestational age is accurate. Some pregnant mothers missed the last color ultrasound examination, so they can calculate the gestational age based on the results of this color ultrasound examination.

3rd time: 21-24 weeks

The third color ultrasound examination is very familiar to pregnant mothers and is also a very significant one, called "color ultrasound for fetal abnormality screening". In some places, it may be called "four-dimensional color ultrasound".

The main purpose of this color Doppler ultrasound is to check whether the fetus has any large, obvious structural deformities. The main lesions include those in the brain, heart, abdominal organs and kidneys, all of which are examined through color ultrasound. Many serious fetal diseases during pregnancy are discovered during this color ultrasound. If there is nothing abnormal in the results of this color ultrasound, the risk of fetal problems will be greatly reduced.