When a pregnant woman takes a pregnancy test, if the fetus has a biparietal diameter of 77mm, it belongs to the late stage of pregnancy, when the fetus is about 36cm in length and weighs about 1300g.
When the fetal biparietal diameter is 77mm, the fetus belongs to the late stage of pregnancy, around 30 weeks, at this time, the fetus weighs about 1,300g, the length is about 36cm, belonging to the stage of rapid brain development, and the lungs are also developing rapidly.
Due to the increasing size of the fetus, the space inside the uterus is gradually decreasing, and the amniotic fluid is also becoming less, at this time, the fetal movement is usually less than the level of the mid-pregnancy.
If you want to know exactly how big the fetus is at 77mm biparietal diameter, you can undergo a 4D ultrasound to determine the size of the fetus and at the same time determine whether there are any congenital malformations in the fetus.
Pregnant women are advised to go to the hospital for regular pregnancy checkups to observe the growth and development status of the fetus and to facilitate successful delivery.