/kloc-what is the accuracy rate of 0/7 weeks B-ultrasound for fetal sex? Generally speaking, the sex of the fetus can be determined by B-ultrasound at about 17 weeks (about 4 months), because the genitals of the fetus have been formed at this time, which can be basically seen by B-ultrasound. However, the accuracy at this time cannot reach 100%. If it is a boy, the accuracy rate can reach about 80%. If it is a girl, the accuracy rate is slightly lower, about 60%.
Generally speaking, the data on the B-ultrasound list include biparietal diameter, abdominal circumference, femur length, fetal sac, fetal heart rate and so on. Placenta, amniotic fluid, umbilical cord and fetal spine can also be observed by B-ultrasound. There is no scientific basis for judging sex from the gestational sac size in B-ultrasound data. The shape and size of gestational sac are determined by many factors, such as pregnancy time, nutrition, implantation position, uterine cavity size and so on. Every pregnant mother's uterine cavity is different, and the shape of pregnancy sac will naturally change with the shape of uterine cavity, which is also related to the situation of pregnant women during examination. For example, some pregnant women hold their urine for a long time, their uterus is flattened, and the shape of the gestational sac looks flat.
In addition, when some pregnant women are pregnant, the implantation position of sperm and eggs is just right, and some positions will be deviated, resulting in different shapes of gestational sacs. Therefore, from the data of B-ultrasound, we can know the sex of the fetus from the shape and size of the gestational sac. This is a saying handed down from the older generation. Pregnant mothers should not take it too seriously. Generally speaking, except for direct observation of fetal reproductive organs from B-ultrasound, other folk sayings can only be referred to.
B-ultrasound to see what the fetus wants 1, fetal sac: fetal sac is only seen in the first trimester. Its size is about 2 cm in diameter at 1.5 months of pregnancy, and it is normal at 2.5 months. The position of fetal sac is normal in the bottom, front wall, back wall, upper part and middle part of uterus. The shape is round, oval and clear. If the fetal sac is irregular, fuzzy and located below, pregnant women may have an abortion with abdominal pain or vaginal bleeding at the same time.
2. Fetal head: normal contour, abnormal defect and deformation, normal midline without displacement and hydrocephalus. BPD stands for biparietal diameter of fetal head, which should reach 9.3 cm or more when pregnant to term. According to the general rule, after 5 months of pregnancy, it basically coincides with the month of pregnancy, that is, the BPD of 28 weeks (7 months) is about 7.0 cm, and that of 32 weeks (8 months) is about 8.0 cm, and so on. After 8 months of pregnancy, it is normal to grow about 0.2 cm per week on average.
3. Fetal heart: strong is normal, weak is abnormal. The normal fetal heart rate is between 120- 160 beats per minute.
4. Fetal movement: If it is strong, it is normal; If it is weak, it may be that the fetus is asleep, or it may be abnormal, which should be comprehensively analyzed in combination with other projects.
5. Placenta: Position indicates the position of the placenta on the uterine wall. The normal thickness of placenta should be between 2.5 and 5 cm. According to a report, calcification is divided into grade III, grade I is the early stage of placental maturity, with uniform echo, which can be seen at 30-32 weeks of pregnancy. Grade Ⅱ indicates that the placenta is close to maturity. Grade Ⅲ indicates that the placenta has matured. The closer to term, the more mature the placenta, and the uneven echo.
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