Pregnant women doing B-ultrasound will affect the health of the fetus.

At present, the sound intensity emitted by the B-ultrasound probe used in clinic is less than 10mW/cm, and the ultrasonic examination time is usually only 5- 10 minutes, and the detection time for various organs is even shorter. Therefore, the B-ultrasound examination does little harm to the fetus and will not affect its physical development. Therefore, pregnant women need not be afraid of B-ultrasound examination during pregnancy, and timely B-ultrasound examination is an important means to ensure the normal development of the fetus.

B-ultrasound should be done throughout pregnancy, morning, evening and evening. Some pregnant mothers don't know the purpose of doing B-ultrasound. In order to find out the sex of the fetus, they do not hesitate to go to many hospitals for repeated B-ultrasound examination, which is not good for both mother and baby. Studies have proved that if the time of B-ultrasound exceeds 20 minutes, it will have irreversible adverse effects on the fetus. Therefore, pregnant women should carry out appropriate B-ultrasound examination according to the requirements of doctors and control the number of B-ultrasound examinations.

How many times can I do B-ultrasound during pregnancy?

1 and b-ultrasound can be used to screen early prenatal birth defects.

Ultrasonic examination can determine the intrauterine development of normal early pregnancy and normal middle and late pregnancy, which can be clearly defined as singleton or multiple pregnancy, and can estimate the fetal size and expected date of delivery. In the third trimester, it can be used to determine the placental grading position, amniotic fluid volume, fetal position and estimate fetal weight. Ultrasound can also be used to screen early prenatal birth defects, which is expected to reduce the birth defect rate by more than 40%. Embryo stagnation, hydatidiform mole and ectopic pregnancy can be found in the early stage, and fetal malformation can be found in the middle and late stage.

2, 3 months should not be repeated ultrasound examination.

Prenatal ultrasound is to emit ultrasonic waves that can't be heard by human ears through the abdominal probe of ultrasonic instrument, and show the ultrasonic image of the fetus in the pregnant woman's stomach. Embryo bud, amniotic sac, placenta and ovary in early pregnancy can be displayed; Most anatomical abnormalities and birth defects of the fetus in the second trimester. Studies have shown that ultrasound is different from radiation, and it has basically no harm and side effects on pregnant women and fetuses. All ultrasonic instruments must pass the safety inspection before leaving the factory. However, it is still considered that ultrasound examination should not be done many times in the first three months of pregnancy.

3. It is more appropriate for pregnant women to do B-ultrasound at 20 weeks of pregnancy.

Clinicians can request ultrasound examination at any time according to the different situations of pregnant women. But generally speaking, it is more appropriate for all pregnant women to have a systematic ultrasound examination at the 20 th week of pregnancy. This kind of ultrasound can confirm the position and attachment of placenta, the growth and development of fetus in uterus (including fetal movement in uterus, heart beating and limb movement) and most anatomical abnormalities and birth defects.

4, pregnant women have special circumstances need to do fetal echocardiography.

Because in the first 3 ~ 4 months of pregnancy, the fetal heart has not yet matured, and it can be transmitted to the fetus through the placenta, which stops the development of the heart and causes deformity. The incidence of fetal congenital heart disease in pregnant women infected with rubella is high. Pregnant women have a history of diabetes, lupus erythematosus, sexually transmitted diseases (syphilis), frequent drinking and drug poisoning. And the probability of teratogenesis is also high. Genetic factors such as family congenital heart disease, previous abortion, premature delivery, stillbirth, history of deformed children, etc. It is also very tall.

What problems can B-ultrasound specifically find out about the fetus?

Experts pointed out that in 2003, the United States formulated guidelines for the use of obstetric ultrasound, which can be divided into four categories, as follows:

Ultrasonic examination in the first week of labor (before 12 weeks) includes excluding ectopic pregnancy, determining fetal heartbeat, estimating gestational age, evaluating whether there are uterine or ovarian tumors, and judging whether there are multiple pregnancies.

The second (12 ~ 24 weeks) or third (24 weeks) perinatal ultrasound continued the first week's fetal growth assessment, amniotic fluid volume measurement, placenta position and fetal position confirmation, and fetal anatomical structure examination. Detailed items of fetal anatomical structure examination include:

1. Neck: ventricle, choroid plexus, septum pellucidum.

2. Thoracic cavity: an empty four-chamber diagram of the heart.

3. Abdomen: the junction of stomach, kidney, bladder, umbilical cord and abdominal wall.

4. spine.

5. Limbs: whether arms and calves exist.

In an emergency, if the pregnant woman has vaginal bleeding, the obstetrician and gynecologist can judge whether it is abortion or other reasons through ultrasound. Or if the fetal position is suspected to be incorrect, the fetal presentation position can be identified by ultrasound, for example, the breech position means that the buttocks come out first.

Special inspection (expert inspection) Special scanning when the basic inspection is in doubt. For example: heart scan, high-order scan, Doppler blood flow examination, etc.

How high is the accuracy of B-ultrasound screening? Experts say that the use of ultrasound in prenatal examination is only a screening method, not a final diagnosis. Generally, there are abnormal conditions, and the probability of being screened by ultrasound is only 80%. The reason is attributed to the characteristics of ultrasound and the growth of the fetus.

Characteristics of ultrasonic wave 1 sound wave: ultrasonic wave is a kind of sound wave that people can't hear. It must penetrate water as a medium, not bone. Thick fat will hinder the examination.

2. Resolution: The resolution of ultrasound cannot identify tiny fetal defects. For example, small ventricular septal defect or arterial arch stenosis is not easy to be diagnosed by ultrasound. Another example is that neural tube defect is usually located in the small hole of coccygeal skin, which is not easy to find before delivery. Therefore, if the amniotic fluid is too much or too little, the fetal weeks are large, the bones are calcified, and the mother's abdominal fat is thick, the detailed structure of the fetus cannot be seen clearly.

Preparation before B-ultrasound examination

1, keep clothes loose and easy to take off.

Loose clothes can save time during examination, and can also relax the nervous mood of pregnant mothers. During the examination, we should take a relaxed attitude and cooperate with the doctor. Being too nervous may affect the effect of the inspection.

2, according to the actual check urine or urine in advance.

When doing B-ultrasound in the first trimester, you need a certain amount of urine in your bladder to see clearly, so it is recommended that pregnant mothers hold their urine in advance. You can drink two cups of boiled water in advance at home to save time when you go to the hospital for examination. If you do B-ultrasound examination in the second and third trimester of pregnancy, you can not only urinate without holding your urine, but also urinate in advance. This is because after three months of pregnancy, the uterus is getting bigger and bigger, and there is more amniotic fluid. Doctors can observe the fetus through amniotic fluid through ultrasonic instruments. If there is urine in the bladder, it may affect the appearance of fetal images.

3, don't eat food that is easy to produce gas.

Such as milk, sweet potato and other foods, are easy to produce gas after eating, which will hinder the penetration of ultrasonic waves and lead to unclear imaging of the organs to be examined.

Matters needing attention in B-ultrasound examination

Precautions before inspection

You can't eat anything for 8 hours before the B-ultrasound examination (that is, after dinner the day before the examination). Eat less greasy food the day before B-ultrasound examination.

When detecting deep organs that are easily disturbed by digestive tract gas, it is necessary to conduct fasting examination or make stricter intestinal preparation. For example, it is best to fast foods that are easy to ferment and produce gas, such as bean products and sugar, for 3 days before the intra-abdominal hepatobiliary and pancreatic examination, and eat a light diet at night 1 day before the examination, and it is required to fast and ban water on the same day.

If the patient wants to take X-ray films of gastrointestinal tract and biliary tract at the same time, ultrasound examination should be performed before the X-ray film or 3 days after the above-mentioned film.

For example, when examining pelvic uterus and its accessories, bladder, prostate and other organs, it is necessary to keep bladder urine before examination. You can drink 1000 ml of boiled water 2 hours before the examination, and don't urinate 2-4 hours before the examination. Be sure to make the bladder feel flatulent. If it's the second or third trimester of pregnancy, you don't need to drink water, so as not to overload the uterus with the bladder. If it is a transvaginal ultrasound examination, you don't need to drink special water.

Matters needing attention in inspection

When examining the heart, you should take off your shoes first, lie flat on the examination bed after a short rest, unbutton your coat and expose your chest for the doctor to examine.

When checking eyes, close the checked eyes. Non-checked eyes will look up at the ceiling, with their jaws slightly upturned to center the pupils. Don't rub your eyes during the inspection, so as to avoid the oily liquid used for inspection flowing into your eyes and damaging your eyes.