39-week fetal biparietal diameter standard: the average biparietal diameter is 9~ 10. The biparietal diameter, also known as BPD, refers to the length of the widest part between the left and right sides of the fetal head, also known as the "large transverse diameter of the head". Doctors often use it to observe the child's development and judge whether there is an imbalance between the head and pelvis and a natural delivery. It should reach more than 9 cm at full 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 cm, and that of 32 weeks (8 months) is about 8 cm, and so on. Calculate the baby's weight with biparietal diameter. Baby's weight = biparietal diameter 900-5200 (g). Don't worry too much if the biparietal diameter is too small. On the one hand, it is caused by measurement errors and errors, and it also has a lot to do with your nutrition. You should strengthen nutrition and eat more foods rich in protein. Your uterus has filled most of your pelvis and abdomen, and your stomach looks big, making it even more inconvenient to move. However, compared with your expectation and slightly nervous mood, physical inconvenience may have become a trivial matter. The baby born now is a full-term baby. He is still gaining weight, and these fat reserves will help regulate the temperature of the fetus after birth. With the improvement of living standards, fetuses are getting heavier and heavier at birth, and some fetuses can weigh more than 4,000 grams at birth. Usually, boys are born heavier than girls.