How big is the pelvis for a normal birth?

When people give birth, they may experience other dangerous phenomena such as dystocia. Therefore, whether the birth is normal or not is also related to the size of the pelvis. Therefore, the size of the pelvis during human reproduction affects whether the birth is normal. So, how big a pelvis is suitable for a normal birth? Let's ask the experts to introduce this issue.

This has some impact on the pelvis, but it is not absolute. If the baby in the belly is too big, it may also lead to failure to give birth naturally.

Usually, external pelvic measurements are performed first, namely, the normal value of the anterior superior iliac spine diameter is 23-26 cm, the normal value of the iliac crest diameter is 25-28 cm, the sacropubic external diameter is greater than 18.5 cm, the normal value of the greater trochanter diameter is 28-31 cm, the normal value of the ischial tuberosity diameter is 8.5-10 cm, and the pubic arch angle is greater than or equal to 90 degrees.

Usually, external pelvic measurements are performed first, namely, the normal value of the anterior superior iliac spine diameter is 23-26 cm, the normal value of the iliac crest diameter is 25-28 cm, the sacropubic external diameter is greater than 18.5 cm, the normal value of the greater trochanter diameter is 28-31 cm, the normal value of the ischial tuberosity diameter is 8.5-10 cm, and the pubic arch angle is greater than or equal to 90 degrees. The transverse diameter of the pelvic outlet refers to the distance between the two ischial tuberosities, which is about 9 cm on average. It is the meridian through which the fetal presenting part passes through the pelvic outlet, and this meridian is closely related to delivery.

When the transverse diameter of the pelvic outlet is slightly short and the sum of the transverse diameter and the posterior sagittal diameter is >15cm, a normal-sized fetus can still be delivered vaginally with close observation. An important part of prenatal examination is to measure the pelvic diameter to determine the mode of delivery. The pelvis has two diameters in its structure. A short anterior-posterior diameter and a wide lateral diameter facilitates the passage of the fetus and allows natural delivery. If the pelvis is naturally narrow, with a long anterior-posterior diameter and a narrow lateral diameter, the fetus will not be easy to deliver and a caesarean section can be chosen. Therefore, although the size of the pelvis has no direct impact on fertility, an upright and "dignified" perfect pelvis is indeed conducive to natural childbirth.

The above is what the experts introduced to us about the issues of pelvis and childbirth, and the relationship between the size of the pelvis and normal delivery. During delivery, pregnant women with smaller pelvises should pay special attention to safety. Once other conditions occur, a caesarean section will be required to ensure the safety of the pregnant woman. Finally, I wish the pregnant woman a smooth delivery.