Clinical manifestations of cephalopelvic disproportion

It is said that natural childbirth is good for both children and adults, but due to special reasons, some people still have difficulty in giving birth naturally, such as uterine contraction and pelvic size. Some pregnant women also experience cephalopelvic disproportion. It is possible that the pelvic inlet is of normal size but the fetal head is large, or the fetal head is of normal size but the pelvic inlet is narrow, which prevents the fetal head from entering the pelvis smoothly. Cephalopelvic disproportion can make natural childbirth more difficult.

Cephalopelvic disproportion refers to the disproportion between the size of the fetal head and the maternal pelvis. Whether the delivery process can be completed smoothly depends on three major factors: labor force, birth canal and fetus. If the three are coordinated and there are no abnormalities, vaginal delivery can be successful. On the contrary, if any one or more of these factors are abnormal or cannot adapt to each other, the delivery process will be obstructed and it may lead to dystocia. Timely detection and treatment of dystocia is the key to reducing neonatal morbidity and mortality and saving the mother and baby from danger. So, what are the symptoms of cephalopelvic disproportion and how to diagnose it?

Steps/Methods:

1. The pregnant woman should empty her bladder, lie on her back with her legs straight. The examiner places his hand above the pubic symphysis and pushes the floating fetal head toward the pelvic cavity. If the fetal head is lower than the plane of the pubic symphysis, it means that the fetal head can enter the pelvis and the head and pelvis are proportional, which is called a negative trans-pubic sign; if the fetal head and the pubic symphysis are on the same plane, it indicates suspected head and pelvic disproportion, which is called a suspected positive trans-pubic sign; if the fetal head is higher than the plane of the pubic symphysis, it indicates obvious head and pelvic disproportion, which is called a positive trans-pubic sign.

2. For pregnant women with a positive trans-pubic sign, they should be asked to take a semi-recumbent position with their legs flexed, and the fetal head trans-pubic sign should be checked again. If it turns negative, it indicates an abnormal pelvic tilt rather than cephalopelvic disproportion. Relative cephalopelvic disproportion means that the pelvis is normal, but the fetus is too large to fit into the pelvis.

3. Differentiation from rickets-induced flat pelvis: Due to rickets in childhood, the bones soften and the pelvis is deformed. The sacral promontory is pressed forward, and the anterior-posterior diameter of the pelvic inlet is significantly shortened, making the pelvic inlet kidney-shaped. The lower part of the sacrum moves backward, losing the normal curvature of the sacrum and becoming straight and tilted backward. The coccyx is hooked and projects toward the pelvic outlet plane. Due to the abduction of the ilium, the diameter between the iliac spines is equal to or greater than the diameter between the iliac crests; due to the eversion of the ischial tuberosity, the angle of the pubic arch increases and the transverse diameter of the pelvic outlet becomes widened.

Note:

Cephalopelvic disproportion refers to the disproportion between the size of the fetal head and the maternal pelvis. Whether the delivery process can be completed smoothly depends on three major factors: labor force, birth canal and fetus. If the three are coordinated and there are no abnormalities, vaginal delivery can be successful. Otherwise, any one or more of the factors are abnormal or cannot adapt to each other.