What does a woman's pelvis of 8.5 mean?

One of the issues that women are most concerned about after becoming pregnant is whether to give birth naturally or by caesarean section. They usually want the baby to grow well, but they are worried that the baby is too big for a natural birth, so they go through the entire pregnancy very cautiously. Whether a pregnant woman gives birth naturally or by caesarean section depends not only on the size of the baby in the belly, but also on many other factors to consider. Among them, the size of the woman's pelvis is also an item that the doctor will check before delivery. When a woman's pelvis is 8.5, pregnant women are most concerned. Here are some explanations from doctors about a woman's pelvis of 8.5 during pregnancy.

Why is the pelvis measured during prenatal check-up?

The channel through which the fetus is delivered is called the birth canal, which is divided into bony birth canal and soft birth canal. The pelvis is the bony birth canal. For the fetus to be delivered from the mother's body, it must first descend from the abdominal cavity through the pelvis, and then pass through the soft birth canal formed by the lower segment of the uterus, cervix, vagina and soft tissue of the pelvic floor. The size and shape of the pelvis play a decisive role in whether childbirth is smooth or not. If the size and shape of the pelvis are abnormal and not compatible with the fetus, the fetus' descent will be blocked, which may lead to dystocia. For this reason, the pelvis must be measured during prenatal examinations.

The pelvis is made up of multiple bones connected by joints and ligaments. The female pelvis is shallow in front and deep in the back, with a certain degree of curvature, and its axis is crescent-shaped. After pregnancy, under the influence of hormones, the ligaments connecting the bones become loose and the joint mobility increases slightly. Abnormalities in the birth canal will directly hinder the delivery of the fetus. Clinically, bone birth canal abnormalities are the most common among birth canal abnormalities. Because the pelvis is relatively fixed, it is possible to check before delivery to determine whether a vaginal delivery is suitable. The purpose of measuring the pelvis during prenatal examinations is to understand the condition of the bony birth canal before delivery and to provide first-hand information for choosing the method of delivery.

Since it is impossible to directly measure the inner diameter of the pelvic cavity, prenatal examinations generally use some surface anatomical landmarks to perform external pelvic measurements to understand the lengths of several pelvic diameters in order to preliminarily estimate whether the pelvis is narrow and whether its shape is normal. Self-test: Is your pelvis normal?

Interspinous diameter: normal value is 23-26 cm.

Inter-iliac crest diameter: normal value is 25-58 cm.

The above two diameters can indirectly infer the transverse diameter of the pelvic inlet. Intertrochanteric diameter: normal value is 28-31 cm. This diameter can indirectly infer the length of the transverse diameter of the mid-pelvis.

Sacropubic external diameter: normal value is 18-20 cm. This is the most important diameter in external pelvic measurement, which can indirectly infer the length of the anterior-posterior diameter of the pelvic inlet. Ischial tuberosity diameter: that is, the transverse diameter of the outlet. The normal value is 8.5-9.5 cm. Pubic arch angle: The normal value is 90 degrees, and less than 80 degrees is abnormal. This angle reflects the angle of the pelvic outlet.

For those whose pelvis is narrow when measured externally, the doctor will also use his fingers (wearing gloves and applying lubricant) to enter the vagina to measure the inside of the pelvis. The following two diameters are measured in the pelvic internal measurement:

Sacropubic internal diameter: normal value is 12.5-13 cm. Intersciatic diameter: The normal value is about 10 cm.

External pelvic measurements are usually taken once during a prenatal check-up, recorded on a card, and not measured again thereafter. There is a new method for measuring the pelvis, namely transvaginal B-ultrasound detection, which is harmless to the mother and child and is more accurate.

When a pregnant woman's pelvis is 8.5, she should listen to the doctor's advice and not worry too much about whether to have a natural birth or a caesarean section. Only by relaxing can the baby develop healthily. Only when the body and baby are healthy, the issue of natural birth or a caesarean section will not be a problem. Plan your diet and life during pregnancy well and wait for the happy meeting with your baby.