At what months is the fetal position determined?

The correct fetal position not only affects whether the delivery is smooth, but is also an important guarantee for the health of the fetus in the mother's body. Especially in the late pregnancy, it is best to have a prenatal check-up every half a month to check whether the fetal position is normal. If the fetal position is not correct, it can also be corrected through some methods. Let us learn about some main inspection methods for whether the fetal position is normal.

In the late stages of pregnancy, a check-up is required at least once every half a month. The fetal position can be checked through B-ultrasound or the four-step palpation method.

1. Ultrasound

B-ultrasound monitoring is intuitive and clear, and can directly observe whether the fetal position is correct.

2. Four-step palpation method

The four-step palpation method is the most commonly used method for prenatal examination and starts after 24 weeks of pregnancy. The four-step palpation method can be used to determine the position and size of the fetus, whether the size of the uterus is consistent with the gestational age, the mode of delivery, fetal presenting part, fetal position, etc., and to estimate the amount of amniotic fluid.

①Pregnant women’s position: Lie on your back after urinating, with your head slightly elevated to expose your abdomen, and your legs slightly bent and spread apart to relax your abdomen.

②) Examiner: Stand on the right side of the pregnant woman to conduct the examination; face the pregnant woman when performing the first three steps; face the pregnant woman's feet when performing the fourth step.

③ Technique

Step 1: The examiner places both hands on the fundus of the uterus, measures the height of the fundus, and estimates whether the size of the fetus is consistent with the gestational age. Then use the fingertips of both hands to push gently alternately to determine the position of the fetus at the fundus of the uterus. If it is the fetal head, it will be hard, round and have a floating ball feeling. If it is the fetal buttocks, it will be soft, wide and slightly irregular in shape.

Step 2: The examiner places his hands on the left and right sides of the abdomen respectively. One hand fixes the abdomen, and the other hand gently presses deeply to examine, alternating between the two hands from top to bottom. The flat and full part you feel is the fetal back, and you can determine whether the fetal back is facing forward, sideways or backward. The deformable uneven parts you touch are the fetal limbs, and sometimes you can feel the fetal limbs moving.

Step 3: The examiner separates the thumb of his right hand from the other four fingers, places it above the pubic symphysis and holds the fetal presenting part to further determine whether it is the fetal head or buttocks, and then pushes left and right to determine whether it is connected. If the presenting part of the fetus can still move left or right, it means that it has not yet been connected to the human pelvis. If engaged, the presenting part cannot be pushed.

Step 4: The examiner places his left and right hands on both sides of the fetal presenting part, and presses deeply downward along the pelvic incision to further verify whether the judgment of the fetal presenting part is correct and determine the degree of the fetal presenting part in the pelvis. When the fetal head is the presenting part, one hand can smoothly enter the pelvic incision, while the other hand is blocked by the bulge of the fetal head, which is called the fetal head protuberance. In occipital presentation, the fetal head protuberance is the frontal bone, which is on the same side as the fetal limbs; in face presentation, the fetal head protuberance is the occipital bone, which is on the same side as the fetal back.

Of course, if you find that the fetus is in an abnormal position in the late pregnancy, you don’t need to be too anxious. You should monitor the fetal heart rate in time. If the fetal heartbeat is normal and there is no abnormality in fetal movement, it will generally not endanger the health of the fetus. If the malposition of the fetus affects the physical delivery, you can also choose a safe delivery method under the guidance and advice of an obstetrician.