The length of the widest part between the left and right sides of the fetal head is the biparietal diameter of the fetus. Many expectant mothers worry that if the fetal biparietal diameter is too large or does not meet the standards, it may lead to difficult labor and cause great harm to the body. Some expectant mothers believe that a small biparietal diameter is a symptom of malnutrition, but these understandings are actually incorrect. So what is the biparietal diameter standard for a 38 week fetus?
At 38 weeks, the fetal length is approximately 47.5cm and the fetal weight is 3100g. The average biparietal diameter is 9.08 ± 0.59cm, the average abdominal circumference is 30.63 ± 2.83cm, and the femur length is 7.20 ± 0.43cm. The thin layer of fur and most of the white fetal fat covering the fetus gradually fall off, and skin wrinkles gradually disappear. These secretions will be swallowed by the fetus along with amniotic fluid and gradually turn black in the intestine. They will be excreted from the body after birth, known as "fetal stool". Let's take a look at the biparietal diameter standard for a 38 week old fetus.
The 38th week belongs to the third week of September pregnancy, so the standard for fetal biparietal diameter at the 38th week should be between 9.0 centimeters and 10.0 centimeters. However, the calculation of fetal biparietal diameter is based on the average value, so the average biparietal diameter at the 38th week is 9.08 ± 0.59.
Pregnant mothers can also use biparietal diameter to calculate fetal weight, which is equal to biparietal diameter multiplied by 900-5200 grams. If the fetal biparietal diameter is too small, there is no need to worry too much. On the one hand, it is caused by measurement errors, and on the other hand, it is also closely related to your nutrition. You should pay attention to nutritional supplementation, and eating more high protein foods can be helpful.
The use of biparietal diameter to determine the developmental size of a baby is only a reference data. As for whether the baby is born naturally or difficult, generally speaking, it needs to be viewed from three aspects, namely the birth canal, labor force, and fetus. Only under the condition of mutual coordination can these three elements lead to a successful delivery outcome. So in the case of abnormal biparietal diameter at 38 weeks of gestation, as long as the birth canal and labor force are normal, vaginal delivery can still be achieved. Expectant parents don't need to worry, as long as they give a good order to have prenatal check ups on time.
