What is the diagnosis of head presentation dystocia?

Dystocia is the most worrying thing for mothers and their families. It is not uncommon for mothers to suffer from head presentation dystocia during delivery. Family members are scared when they hear the word "dystocia". They are afraid that something might happen to the mother and the child. In fact, under normal circumstances, pregnant women will undergo various examinations before delivery to avoid dystocia. Now let us understand the diagnoses of head presentation dystocia.

Head presentation dystocia refers to a non-occipital anterior fetal head that is blocked from turning in the pelvic cavity, resulting in a persistent occipital posterior or transverse position; or due to poor flexion of the fetal head, the fetal head is extended to varying degrees, resulting in face presentation, forehead presentation, vertex presentation, etc. This type of dystocia is caused by the incompatibility of the maximum diameter of the fetal head with the diameters of the bony birth canal.

(I) Medical history: There are usually no special findings during pregnancy, and about 1/3 of cases experience premature rupture of membranes during labor.

During labor, the cervix dilates slowly, the labor process stagnates, cervical edema is prone to occur, the cervix is ​​almost fully dilated and the feeling of defecation appears prematurely, the deceleration period is prolonged, and the cervical edge fails to flatten or disappear. Sometimes the fetal hair can be seen at the vaginal opening, but the labor process progresses very slowly, and the second stage of labor is often prolonged. Therefore, there is often secondary uterine atony and the parturient is prone to fatigue.

(B) Physical examination

1. It is difficult to palpate the fetal back in the abdomen, but the fetal body may be palpated. The fetal heart rate is mostly on one side of the mother's abdomen or near the midline of the abdomen.

2. Anal examination often feels that there is a large space in the back half of the pelvic cavity, and the pubic symphysis is tightly stuck to the fetal head. If it is occipital posterior position, it is easy to touch the large fontanelle located in the left or right front of the pelvis; if it is occipital transverse position, it is easy to see thickening of the anterior lip of the cervix, which is actually edema.

3. Vaginal examination

(1) When the sagittal suture of the fetal head is close to or consistent with the transverse diameter of the pelvis, it is called occipital transverse position, and the helix is ​​located at about 12 o'clock in the pelvic cavity. If the biparietal diameter has dropped to the level of the ischial spine or below, it is called low occipital transverse position; if the presenting part is high, the sagittal suture of the fetal head is embedded in the transverse diameter of the pelvic entrance, which is called cephalopelvic inclination inequality. If the fetal head is embedded on one side of the top and the sagittal suture is biased backward, it is anterior unequal tilt; if the sagittal suture is biased forward, it is posterior unequal tilt. This type is often related to a slightly flat pelvis or a straight sacrum.

(2) If the sagittal suture of the fetal head is close to or consistent with the anteroposterior diameter of the pelvis, the greater fontanelle is in front, the lesser fontanelle is in the back, and the helix is ​​facing backwards, it is the occipital posterior position. When the fetal head is in the inlet plane, the fetal head is in a non-bending or non-elevated position, and the posterior fontanelle points to the sacral promontory, it is called the high straight occipital posterior position; when the fetus is in the outlet plane, the anterior fontanelle points to the pubic symphysis, it is called the straight occipital posterior position. (3) Ultrasound examination can clearly determine the position of the fetal head based on the biparietal diameter, facial and occipital position, and make a timely diagnosis.