At what weeks of pregnancy does the fetal position begin to become fixed?

The formation of life is a very magical thing. A healthy baby needs to start from a fertilized egg, grow slowly in the mother's belly until it comes into this world. At the beginning, the fetus can move freely in the mother's belly. After a period of time, when the fetus grows bigger, the fetus will not move in the belly. This is what we often call the fixed fetal position. So, at what weeks of pregnancy does the fetal position begin to become fixed?

When does the fetal position become fixed?

Generally speaking, before 28 weeks (7 months) of pregnancy, because there is more amniotic fluid and the fetus is smaller, the fetus has a larger range of movement in the uterine cavity and the fetal position is easy to change. After 32 weeks (8 months) of pregnancy, the fetus grows rapidly, the amniotic fluid decreases relatively, and the position of the fetus in the uterine cavity is basically fixed.

There are three fetal positions: cephalic position, breech position, and transverse position; transverse position is rare and is an abnormal fetal position. In fact, during the birth process, the fetal head will go down, rotate, and other movements as the uterus contracts to adapt to the changes in the diameters of the pelvis until it is delivered smoothly. If descent and rotation are obstructed, difficult labor will occur, which is medically known as "cephalic presentation dystocia". This is actually the most common type of "difficult labor" during childbirth for pregnant women who are judged by doctors to have a normal fetal position.

Breech presentation is also an abnormal fetal position, which is much less common than cephalic presentation. During the 7th to 8th month of pregnancy, the doctor will instruct the pregnant woman to do some actions to change the fetal position. However, if the fetus is particularly large, there is too little amniotic fluid, the umbilical cord is wrapped around the neck, or the pelvis is abnormal, the fetal position will be difficult to correct. At the same time, there is a certain risk in forcibly changing the fetal position of a fetus with the umbilical cord wrapped around the neck. At 36 weeks, the doctor will ask you to do a color ultrasound to determine the fetal position, the umbilical cord, and the mode of delivery.