breech presentation
Introduction
Introduction to the breech Breechpresentation is the most common abnormal fetal position, accounting for 3% to 4% of the total number of full-term deliveries in pregnancy. Because the fetal hip is larger than the fetal head, there is no obvious deformation of the fetal head after delivery, but it is often difficult to deliver, and the umbilical cord prolapse is more common, which increases the perinatal mortality, which is 3 to 8 times that of the first exposure. The breech is exposed with the tibia as the indication point, and there are 6 kinds of fetal positions in the left front, the left side, the left side, the right front, the right side and the right side. basic knowledge Probability ratio: 2.1% of pregnant women Susceptible population: pregnant women Mode of infection: non-infectious Complications: neonatal asphyxia umbilical cord prolapse premature rupture of membranes brachial plexus injury premature delivery hydrocephalus cerebral palsy
Cause
Buttocks
Too much amniotic fluid (30%):
Fetal in the uterine cavity is too large for amniotic fluid, the maternal abdominal wall is loose and the amniotic fluid in premature infants is relatively large, the fetus is free to move freely in the uterine cavity to form the breech presentation. The amount of amniotic fluid in normal pregnancy increases with the increase of gestational age, and gradually decreases gradually in the last 2 to 4 weeks. The amniotic fluid volume in the full-term pregnancy is about 1000ml (800-1200ml). If the amount of amniotic fluid exceeds 2000ml in any period of pregnancy, it is called Too much amniotic fluid.
Uterine malformation (25%):
The fetus has limited uterine malformation in the uterine cavity (such as single-horned uterus, double-horned uterus, etc.), fetal malformations (such as hydrocephalus, etc.), fetal and oligohydramnios, etc., prone to hip first exposure. Uterine malformation, also known as uterine dysplasia, is a congenital disorder and the most common form of genital malformation. Some patients with uterine malformations may have no symptoms, and menstruation, sexual life, pregnancy, childbirth, etc. are also abnormal, so that they are not found for life, or even found during physical examination.
Narrow pelvis (20%):
The fetal head is blocked by the pelvis, the placenta previa, the tumor obstructing the pelvis, etc., and the breech is also prone to occur.
In each part of the carcass, the fetal head is the largest, the shoulder is smaller than the fetal head, and the fetal hip is the smallest. When the head is first exposed, the fetal head is delivered immediately, and other parts of the body are delivered immediately, while the hips are different when exposed first, and the small but soft buttocks First delivery, the largest fetal head is finally delivered. In order to adapt to the conditions of the birth canal, the fetal buttocks, shoulders, and fetal heads must be adapted to the conditions of the birth canal according to a certain mechanism, so it is necessary to grasp the three parts of the fetal hip, shoulder and fetal head. Childbirth mechanism:
1. After the fetal calf is delivered, the fetal buttocks are connected to the right slant diameter of the pelvic entrance with the intertrochanteric diameter. The tibia is located in the right front, the fetal hips gradually decrease, the front hips descend slightly, so the position is lower, and the resistance reaches the pelvic floor. After that, the front hip rotates within 45° of the right side of the mother, so that the front hip is located behind the pubic symphysis. At this time, the intertrochanteric diameter is consistent with the anterior and posterior diameter of the parent pelvic outlet, the fetal hips continue to descend, and the carcass flexes to accommodate the curvature of the birth canal. The posterior hip is delivered from the anterior aspect of the perineum, and the carcass is slightly straightened, so that the anterior hip is delivered from the pubic bone, and then the legs are delivered. When the fetal hips and the lower limbs are delivered, the carcass rotates outside, so that the carcass rotates outside. The tire back turns to the front or to the right.
2, the shoulder is delivered when the tire rotates outside the line, the fetal shoulder diameter is connected to the right slant diameter or transverse diameter of the pelvic entrance, and gradually descends along the diameter line. When the shoulder reaches the pelvic floor, the front shoulder rotates to the right 45 ° Turn to the lower pubic arch, so that the shoulder diameter is consistent with the anterior and posterior diameter of the pelvic outlet. At the same time, the cartilage lateral flexion causes the posterior shoulder and the posterior upper limb to be delivered from the perineal anterior border. The anterior shoulder and the anterior upper limb are delivered from the pubic arch.
3. When the fetal head passes through the perineum, the sagittal suture of the fetal head is connected to the left oblique or transverse diameter of the pelvic inlet, and gradually descends along the diameter line, while the fetal head is flexed, and when the occipital bone reaches the pelvic floor, The fetal head rotates 45° to the left front of the mother, so that the occipital bone is united toward the pubic symphysis, and the fetal head continues to descend. When the occipital inferior fossa reaches the lower edge of the pubic arch, the anterior humerus is used as the fulcrum, and the fetal head continues to bend and bend, so that the face, face and amount The ministry was delivered from the perineal anterior border, and the occiput was delivered from the pubic arch.
Prevention
Buttock prevention
Clinically, the advanced B-mode ultrasound, fetal heart sound monitor, comprehensive evaluation of the fetus on the buttocks, and the correct choice of delivery methods. Before the gestation period, 30 weeks before the gestation, the first spleen can turn itself to the first exposure. If the laparotomy is still 30 weeks after pregnancy, it should be corrected. If you still can't correct it before birth, you can choose the mode of delivery for cesarean section to reduce the harmful consequences of gluteal exposure.
Complication
Buttocks first complication Complications neonatal asphyxia umbilical cord prolapse fetal membrane premature rupture brachial plexus injury premature hydrocephalus cerebral palsy
Can cause multiple complications of the fetus:
1. Injury: intracranial hemorrhage, spinal injury, brachial plexus injury, fracture, visceral injury.
2, fetal and neonatal asphyxia: common causes are umbilical cord prolapse, premature rupture of membranes, umbilical cord is difficult to come out after pressure, meconium inhalation, prolonged labor and so on.
3, premature delivery.
4, congenital malformation: congenital dislocation of the hip, hydrocephalus, no brain, meningocele, muscle atrophy.
5, long-term effects: cerebral palsy, brain development retardation, neurological spasm and so on.
Symptom
Symptoms of breech presentation Common symptoms: uterine contraction, fetus, incomplete breech, first fetus, single arm, first cervix, umbilical cord blood circulation disorder, premature rupture of membranes, abnormal position, asphyxia, postpartum hemorrhage
1, clinical manifestations
Pregnant women often feel a round and hard fetal head under the ribs. Because the fetal hips can not be close to the lower uterus and the cervix, it often leads to weak uterine contractions and slow cervical dilatation, resulting in prolonged labor.
2, abdominal examination
The uterus is longitudinally elliptical, and the longitudinal axis of the fetus is consistent with the longitudinal axis of the mother. At the bottom of the uterus, the round and hard can be touched. The fetal head with a floating sensation is sometimes pressed. The pubic symphysis can touch irregular, soft and wide. Fetal buttocks, the fetal heart is heard most clearly above and to the left (or right).
3, anus examination and vaginal examination
When the anus is examined, it can touch the soft and irregular fetal buttocks or touch the fetal foot, the fetal knee. If the position of the fetal buttocks is high, if the anal examination cannot be determined, a vaginal examination is needed. When the vaginal examination is performed, the degree of cervical dilation and the presence or absence of the cervix are observed. Umbilical cord prolapse, if the membrane is broken, it can directly contact the fetal hip, external genitalia and anus. At this time, it should be distinguished from the facial surface. If it is fetal buttocks, it can touch the anus and the two ischial nodules in a straight line, fingers Put into the anus, there is a contraction of the annular sphincter. If you take out your fingers, you can see meconium. If it is a face, the mouth and the two metatarsal points are triangular. The finger can be placed in the entrance to reach the gums and the arched mandible. When it is, it should be differentiated from the baby hand.
4, B-type ultrasound examination
Can accurately detect the type of hip first exposed and the size of the fetus, fetal head posture and so on.
According to the posture taken by the two lower limbs, it is divided into:
1, single hip first exposed or straight hip first dew (frank breech presentation): fetal double hip joint flexion, knee joint straight extension, with the hip as the first exposure, the most common.
2, complete breech presentation or complete breech presentation: fetal double hip joint and knee joint flexion is like sitting cross-legged, with the buttocks and feet as the first exposure, more common.
3, incomplete breech presentation (incomplete breech presentation): one foot or two feet, one knee or both knees or one foot and one knee for the first exposure, the knee first exposed is temporary, after the beginning of labor, turn to the first exposed, less see.
Pregnant women often feel a round and hard fetal head under the ribs. Because the fetal hips can not be close to the lower uterus and the cervix, it often leads to weak uterine contractions and slow cervical dilatation, resulting in prolonged labor.
The effect on the mother's body is irregular in the shape of the fetus and hip. It can not be close to the lower part of the uterus and the cervix. It is prone to premature rupture of membranes or secondary uterine contraction, which increases the chance of puerperal infection and postpartum hemorrhage. Pulling, it is easy to cause cervical tear and even extend to the lower part of the uterus.
The impact on the fetus is uneven, the pressure on the anterior amniotic sac is uneven, often the premature rupture of the membrane, the umbilical cord is easy to escape, the umbilical cord can cause fetal distress or even death, due to the difficulty of pulling out the fetal head, new life can occur. Asphyxia, hip plexus injury and intracranial hemorrhage.
Examine
Check of the breech
1, B-ultrasound: B-ultrasound is the most accurate way to check the fetal position, usually in the second trimester can be checked. Secondly, B-ultrasound is an ultrasound imaging system, which generally does not affect the fetus.
2, fetal heart sound monitor: through the fetal heart sound to understand the fetal heart position, and then according to the fetal physiological structure characteristics to determine the fetal position, the inspection method is not accurate B-ultrasound.
Diagnosis
Hip first exposure diagnosis
If the fetus is broken, it can directly contact the fetal hip, external genitalia and anus. At this time, attention should be paid to the identification of the face.
1, clinical manifestations: pregnant women often feel a round and hard fetal head under the ribs. Because the fetal hip can not be close to the lower uterus and the cervix, often leading to uterine contraction, cervical dilatation is slow, resulting in prolonged labor.
2, abdominal examination: the uterus is a vertical ellipse, the longitudinal axis of the fetus is consistent with the longitudinal axis of the mother. At the bottom of the palace, you can touch the tire head that is round and hard, and sometimes has a floating ball feeling; the irregular, soft and wide fetal hips can be touched above the pubic symphysis, and the fetal heart is heard most above and to the left (or right). clear.
3, anal examination and vaginal examination: anus examination, can touch soft and irregular fetal buttocks or touch the fetal foot, fetal knee. If the position of the fetal buttocks is high and the anal examination cannot be determined, a vaginal examination is required. During vaginal examination, understand the degree of cervical dilatation and the presence or absence of umbilical cord prolapse. If the membrane is broken, it can directly contact the fetal hip, external genitalia and anus. At this time, attention should be paid to the identification of the face. If it is a fetal buttocks, the anus can be touched in a straight line with the two ischial nodules. The finger is placed in the anus and has an annular sphincter contraction. If it is a face, the mouth and the two metatarsal points are triangular, and the finger can be placed in the entrance to reach the gums and the arched mandible. If it touches the fetal foot, it should be differentiated from the fetal hand.
4, B-type ultrasound examination: can accurately detect the type of hip first exposure and fetal size, fetal head posture.
