The normal fetal position is when the baby's head is facing downward, known as cephalic presentation. When the baby's buttocks are positioned downward in the womb, it is called breech presentation. Breech presentation is a relatively common abnormal fetal position, occurring in approximately 4% of cases.Based on the position of the fetus's lower limbs, breech presentation can be classified into three types:
① Single breech presentation: The fetus's hips are flexed, knees are extended, and the lowest part of the body is the buttocks;
② Complete breech presentation: Both hip and knee joints are flexed, resembling a cross-legged sitting position, with the buttocks and feet presenting first;
③ Incomplete breech presentation: The fetus presents with one foot or both feet, one knee or both knees, or one foot and one knee.Among these three presentations, complete breech presentation is most favorable for vaginal delivery, followed by single breech presentation. Incomplete breech presentation is not suitable for vaginal delivery; cesarean section is recommended.
What adverse effects does breech presentation pose to mother and fetus?
Due to the irregular shape of the presenting part—particularly in incomplete breech presentation—it cannot adhere tightly to the lower uterine segment and cervical os like a fetal head, often leaving gaps that predispose to premature rupture of membranes. During labor, uterine contractions may become ineffective, prolonging delivery and increasing risk of postpartum hemorrhage.Premature rupture of membranes in breech presentations also increases the risk of cord prolapse, occurring approximately 10 times more frequently than in cephalic presentations.Premature rupture of membranes may also lead to preterm birth, increasing neonatal mortality. During breech delivery, the final presentation of the fetal head often results in difficult delivery, potentially causing neonatal asphyxia, brachial plexus injury, intracranial hemorrhage, or even stillbirth due to prolonged head delivery. Among fetal parts, the head is largest, shoulders smaller than the head, and buttocks smallest.During cephalic delivery, once the largest fetal head is delivered, the smaller shoulders and buttocks follow smoothly without difficulty. In breech delivery, however, the smallest part—the buttocks—is delivered first, followed by the largest part—the head. Consequently, after the buttocks and shoulders are delivered, the head often becomes stuck.When the fetal body is delivered but the head remains obstructed in the vagina, the umbilical cord—the "lifeline" connecting the placenta to the fetal umbilicus—becomes compressed between the fetal head and the vaginal wall. If the head is not delivered within 5 to 6 minutes after the body emerges, prolonged obstruction of umbilical blood flow can cause severe fetal hypoxia and death due to extended oxygen deprivation.During head extraction, compression or traction may damage the brachial plexus nerves. Alternatively, excessive molding of the head during delivery can cause severe consequences like intracranial hemorrhage due to excessive overlapping or displacement of the skull bones.So, can breech babies still be delivered vaginally? Should all breech presentations be managed with cesarean section?
The approach to breech delivery should be guided by the principle of "selective intervention." The decision must be based on a comprehensive assessment of fetal size, pelvic dimensions, type of breech presentation, and the presence of any pregnancy complications or comorbidities.Cesarean delivery is indicated for women with pelvic stenosis, fetal weight >3500g, incomplete breech presentation, advanced maternal age with nulliparity, or a history of dystocia. Those not meeting these criteria may opt for vaginal delivery. Women undergoing vaginal delivery should avoid standing or walking and rest in a lateral recumbent position to prevent umbilical cord prolapse.Upon membrane rupture, immediately notify the physician to monitor fetal heart rate to promptly detect and manage cord prolapse. If cord prolapse occurs while cervical dilation is incomplete and fetal heart rate remains normal, an emergency cesarean section is required to deliver the infant. The most critical measure for preventing and managing breech presentation is regular prenatal care.Breech presentation is relatively common at 30 weeks gestation. At this stage, amniotic fluid volume is abundant, the fetus is still relatively small, and uterine space is relatively ample. Consequently, many breech presentations spontaneously convert to cephalic presentation.After 30 weeks of gestation, fetal growth accelerates, and the fetus becomes relatively larger. However, the volume of amniotic fluid in the uterus remains largely unchanged, reducing the available space within the uterine cavity. This diminishes the likelihood of spontaneous fetal rotation, necessitating timely intervention to facilitate conversion from breech to cephalic presentation.
The following methods are commonly available:
1. Knee-chest position.The pregnant woman should empty her bladder, loosen her waistband, and kneel on the bed. Her thighs should be vertical, forming a right angle with the bed surface, with her body leaning forward toward the bed. This position should be maintained twice daily for approximately 15 minutes each session, continuing for one week. The knee-chest position allows the fetal buttocks to withdraw from the pelvic cavity. By altering the fetus's center of gravity, it helps position the fetal head downward and the buttocks upward, thereby correcting the fetal position.
2. Laser irradiation or moxibustion at the Zhi Yin acupoint. Located on the outer side of the little toe, approximately 0.1 cun from the lateral corner of the toenail, this point is treated with laser irradiation or moxa stick application. Perform once daily for 15–20 minutes, with 5–7 sessions constituting one course of treatment. Loosen the waistband during treatment.Combining this with the knee-chest position yields better results.
⒊ External version. For cases where the above methods fail to correct fetal position, external version may be performed between 32 and 34 weeks of gestation. Advanced gestational age often complicates the procedure due to fetal size, potentially leading to difficulty or failure.
Procedure: The pregnant woman lies supine on the examination table with pants removed to expose the abdomen. Knees are flexed and slightly abducted to relax the abdominal wall.The practitioner stands on the mother's right side. On the abdominal wall, one hand grasps the fetal head while the other grasps the fetal buttocks. The hand holding the head gently pushes it along the fetal abdomen, maintaining cephalic flexion, toward the pelvic inlet. Simultaneously, the other hand lifts the buttocks upward until the head-down position is achieved.The version maneuver must be performed gently; avoid forceful techniques to prevent complications such as premature placental abruption. If significant resistance is encountered during the procedure, discontinue immediately; never persist with excessive force.Fetal heart tones must be monitored both before and after the procedure. If abnormal heart tones or frequent, intense fetal movements occur post-maneuver, this may indicate complications like cord entanglement during rotation. The fetus should be repositioned into breech presentation to relieve the entanglement. After repositioning, observation should continue for at least half an hour until fetal heart tones normalize and frequent movements cease before concluding monitoring.