Narrow pelvis

Introduction The pelvic diameter line is too short or abnormal in morphology, resulting in the pelvic cavity being smaller than the limit of the first exposed part of the fetus, which hinders the decline of the first exposed part of the fetus and affects the smooth progress of the labor process, which is called the narrow pelvis. A narrow pelvis can be too short or multiple short lines, or a narrow plane or multiple planes. When a radial line is narrow, it is necessary to observe the size of other radial lines in the same plane, and then comprehensively analyze the size and shape of the entire pelvis to make a correct judgment.

Cause

The softening of the bone causes the pelvis to deform. The entrance of the pelvis is transversely kidney-shaped, and the sac is protruding forward. The anterior and posterior diameter of the pelvic entrance is obviously shortened. The lower part of the humerus is straightened and moved backwards. The tailbone is anteriorly tilted and the humerus abducts the diameter of the iliac spine. The diameter, the ischial tuberosity valgus increases the angle of the pubic arch and the diameter of the ischial tuberosity. The pelvic diameter line is too short or abnormal in morphology, which causes the pelvic cavity to be smaller than the limit of the first exposed part of the fetus, which hinders the decline of the first exposed part of the fetus and affects the smooth progress of the labor process.

an examination

Related inspection

Laparoscopic

The pelvis is a constant factor during childbirth. The narrow pelvis affects the decline and internal rotation of the fetal position and the exposed part of the fetus in the delivery mechanism, and also affects contractions. The pelvis is an important factor to consider when estimating the difficulty of childbirth. During pregnancy, you should check whether the pelvis is abnormal, whether the head basin is not called, and make a diagnosis early to determine the appropriate mode of delivery.

1. History Ask about whether pregnant women have rickets, polio, polio, spinal and hip tuberculosis, and traumatic history. If you are a mother, you should know whether there is a history of dystocia and its causes, whether the newborn has a birth injury or not.

2. General examination and measurement of height, if the height of pregnant women is below 145cm, should be alert to small pelvis. Pay attention to the body shape of the pregnant woman, whether there is squatting in the gait, whether there is a spine or hip deformity, whether the Mie's diamond-shaped nest is symmetrical, whether there is a sharp abdomen or a drooping abdomen.

3. Abdominal examination

(1) Abdominal morphology: pay attention to the abdominal type, measure the length of the upper uterus and the abdominal circumference, and observe the relationship between the first exposure of the fetus and the pelvis by B-mode ultrasound, and also measure the double top diameter, breast diameter, abdominal diameter and femur length of the fetal head. Predict fetal weight and determine whether it can pass through the bone birth canal.

(2) abnormal fetal position: pelvic inlet stenosis often because the head basin is not called, the fetal head is not easy to enter the basin, resulting in abnormal fetal position, such as the first gluteal, the first exposed. The middle pelvic stenosis affects the rotation of the fetal head that has entered the basin, resulting in continuous occipital transverse position and posterior occipital position.

(3) Estimation of head and basin relationship: Under normal circumstances, some pregnant women should be in the basin 2 weeks before the expected date of delivery. If the birth is still in place and the fetal head is still not in the basin, the head basin relationship should be fully estimated. Check the specific method of whether the head basin is commensurate: pregnant women empty the bladder, supine, legs straight. The examiner places his hand over 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 basin. The head basin is symmetrical, which is called the trans-shadow sign. If the fetal head and the pubic symphysis are in the same plane, it means that the suspicious head basin is not called. Positive; if the fetal head is higher than the pubic symphysis plane, it means that the head basin is obviously not called, which is called positive across the shame. For pregnant women with positive cross-symptoms, they should take the two-leg flexion semi-recumbent position and re-examine the fetal head cross-symptom sign. If it turns negative, it indicates that the pelvic inclination is abnormal, not the head basin.

4. Pelvic measurement

(1) Measurement outside the pelvis: 1 cm of each radial line was measured as a skewed pelvis.

(2) Measurement in the pelvis: Abnormalities in the lateral pelvis are found, and intrapelvic measurements should be performed. The diagonal diameter is <11.5cm, and the sacral protrusion is a flat pelvic entrance plane, which belongs to the flat pelvis. The pelvic plane stenosis and stenosis of the pelvic outlet plane often coexist. The anterior curvature of the humerus, the diameter of the ischial spine, and the width of the ischial incision (ie, the width of the sacrospinous ligament) should be measured. If the diameter of the ischial spine is <10cm, the width of the ischial incision is <2, which is the plane of the middle pelvis. If the diameter of the ischial tuberosity is <8 cm, the sagittal diameter after the exit should be measured and the mobility of the appendix joint should be examined to estimate the degree of stenosis of the pelvic outlet plane. If the sum of the ischial tuberosity and the posterior sagittal diameter is <15 cm, the pelvic outlet plane is narrow.

Differential diagnosis

(1) The obvious head basin is not called: the outer diameter of the shame is <16cm, and the anterior and posterior diameter of the pelvis is <8.5cm. The full-term live fetus cannot enter the basin and cannot be delivered through the vagina. Caesarean section should be delivered near the expected date of delivery or after delivery.

(2) mild head basin is not called: the outer diameter of the shame is 16 ~ 18cm, the anterior and posterior diameter of the pelvis is 8.5 ~ 9.5cm, the full-term live birth weight is <3000g, the fetal heart rate is normal, and the trial production should be under strict supervision. If there is uterine atony during the trial production, the unruptured membrane may be artificially ruptured when the cervix is expanded by 3 cm. If the uterine contraction is strong after the rupture of the membrane, the labor process progresses smoothly, and most of them can be delivered vaginally. If the trial production is 2 to 4 hours, the fetal head is still unable to enter the basin, or accompanied by fetal distress signs, should be promptly cesarean section to end the delivery. If the membrane is broken, in order to reduce the infection, the trial production time should be shortened appropriately.

The pelvis is a constant factor during childbirth. The narrow pelvis affects the decline and internal rotation of the fetal position and the exposed part of the fetus in the delivery mechanism, and also affects contractions. The pelvis is an important factor to consider when estimating the difficulty of childbirth. During pregnancy, you should check whether the pelvis is abnormal, whether the head basin is not called, and make a diagnosis early to determine the appropriate mode of delivery.

1. History Ask about whether pregnant women have rickets, polio, polio, spinal and hip tuberculosis, and traumatic history. If you are a mother, you should know whether there is a history of dystocia and its causes, whether the newborn has a birth injury or not.

2. General examination and measurement of height, if the height of pregnant women is below 145cm, should be alert to small pelvis. Pay attention to the body shape of the pregnant woman, whether there is squatting in the gait, whether there is a spine or hip deformity, whether the Mie's diamond-shaped nest is symmetrical, whether there is a sharp abdomen or a drooping abdomen.

3. Abdominal examination

(1) Abdominal morphology: pay attention to the abdominal type, measure the length of the upper uterus and the abdominal circumference, and observe the relationship between the first exposure of the fetus and the pelvis by B-mode ultrasound, and also measure the double top diameter, breast diameter, abdominal diameter and femur length of the fetal head. Predict fetal weight and determine whether it can pass through the bone birth canal.

(2) abnormal fetal position: pelvic inlet stenosis often because the head basin is not called, the fetal head is not easy to enter the basin, resulting in abnormal fetal position, such as the first gluteal, the first exposed. The middle pelvic stenosis affects the rotation of the fetal head that has entered the basin, resulting in continuous occipital transverse position and posterior occipital position.

(3) Estimation of head and basin relationship: Under normal circumstances, some pregnant women should be in the basin 2 weeks before the expected date of delivery. If the birth is still in place and the fetal head is still not in the basin, the head basin relationship should be fully estimated. Check the specific method of whether the head basin is commensurate: pregnant women empty the bladder, supine, legs straight. The examiner places his hand over 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 basin. The head basin is symmetrical, which is called the trans-shadow sign. If the fetal head and the pubic symphysis are in the same plane, it means that the suspicious head basin is not called. Positive; if the fetal head is higher than the pubic symphysis plane, it means that the head basin is obviously not called, which is called positive across the shame. For pregnant women with positive cross-symptoms, they should take the two-leg flexion semi-recumbent position and re-examine the fetal head cross-symptom sign. If it turns negative, it indicates that the pelvic inclination is abnormal, not the head basin.

4. Pelvic measurement

(1) Measurement outside the pelvis: 1 cm of each radial line was measured as a skewed pelvis.

(2) Measurement in the pelvis: Abnormalities in the lateral pelvis are found, and intrapelvic measurements should be performed. The diagonal diameter is <11.5cm, and the sacral protrusion is a flat pelvic entrance plane, which belongs to the flat pelvis. The pelvic plane stenosis and stenosis of the pelvic outlet plane often coexist. The anterior curvature of the humerus, the diameter of the ischial spine, and the width of the ischial incision (ie, the width of the sacrospinous ligament) should be measured. If the diameter of the ischial spine is <10cm, the width of the ischial incision is <2, which is the plane of the middle pelvis. If the diameter of the ischial tuberosity is <8 cm, the sagittal diameter after the exit should be measured and the mobility of the appendix joint should be examined to estimate the degree of stenosis of the pelvic outlet plane. If the sum of the ischial tuberosity and the posterior sagittal diameter is <15 cm, the pelvic outlet plane is narrow.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.