Fetal biparietal meridian standard

The fetal biparietal diameter is an important indicator for predicting and evaluating the health of the fetus in the pregnant woman's belly, and it is also one of the prerequisites for whether the pregnant woman can eventually give birth naturally. Generally speaking, the biparietal diameter of the fetus is about 7 cm at 28 weeks of pregnancy, and about 8 cm at 32 weeks of pregnancy, and so on. If the biparietal diameter of the fetus is too large, if the pregnant woman chooses to give birth naturally, it is easy to cause dystocia.

1. The meaning of fetal biparietal diameter

The fetal biparietal diameter refers to the length of the widest part between the left and right sides of the fetal head, also known as the "great transverse diameter of the head." Also known as BPD, doctors often use it to observe fetal development, determine whether there is cephalopelvic disproportion, and ensure a smooth delivery.

2. Fetal biparietal diameter standard

The standard for biparietal diameter of a 12-week fetus: The fetus grows to 4.58 cm, the external genitalia begin to develop, any deformities can be revealed, and the calcification of the skull becomes more complete. The skull halo is clear, the biparietal diameter can be measured, obvious deformities can be diagnosed, and the internal organs tend to become more complete afterwards. It should reach 9.3 cm or more at full term. After 8 months of pregnancy, an average weekly growth of about 0.2 cm is normal. When the due date cannot be determined by CRL (crown-rump length) in the early stages of pregnancy, BPD is often used to predict it; after the second trimester, this data is often also needed to be measured when estimating the fetal weight.

3. What to do if the fetus's biparietal diameter is too large

The larger biparietal diameter of the fetus is a sign of larger fetal development, which is directly related to the good nutrition and low activity level of the expectant mother. It shows that the expectant mother's adequate nutrition causes the fetus to grow larger. This is a common symptom nowadays and there is no need to worry as long as there is no abnormality in the fetal head. However, if the biparietal diameter of the fetus is too large, the first thing to consider is hydrocephalus. It is recommended to pay attention to checking the fetal brain during B-ultrasound to rule out the possibility of abnormal development of the baby.

4. What to do if the fetus's biparietal diameter is small

There are many reasons for the small biparietal diameter of the fetus, such as: the influence of harmful factors such as infection, malnutrition, poisoning, radiation, etc. in the mother's early pregnancy can affect the fetal brain development; if the child himself suffers from metabolic diseases, chromosomal abnormalities, etc., it can also cause microcephaly in the child; some children's microcephaly is familial, which is called familial hereditary microcephaly; the biparietal diameter of the fetus is also directly related to nutritional status. A small biparietal diameter cannot be ruled out as being caused by irregular menstruation, inaccurate gestational age or errors in B-ultrasound measurement. If there are no obvious developmental abnormalities, there is no need to worry too much. It is recommended to pay attention to the regularity of life and diet, pay attention to strengthening nutrition, eat more high-protein foods, and have regular physical examinations.