Severe pain after giving birth

Introduction The labor pain after labor is caused by the lack of amniotic fluid. For labor, pregnant women have severe pain. In the third trimester of pregnancy, the amount of amniotic fluid is less than 300ml, called oligohydramnios. In the early and middle stages of pregnancy, the amniotic fluid is too small, mostly ending in miscarriage. When the amniotic fluid is too small, the amniotic fluid is viscous, turbid, and dark green. In the past, the incidence of oligohydramnios was considered to be about 0.1%. However, in recent years, due to the widespread use of B-mode ultrasound, the detection rate of oligohydramnios is 0.5% to 4%, and the incidence rate has increased. Too little amniotic fluid is valued because it seriously affects the prognosis of perinatal children.

Cause

Because the amniotic fluid production and circulatory mechanism has not been fully elucidated, there are many cases of oligohydramnios caused by unknown causes, and the following cases are common in clinical practice.

(1) Causes of the disease

Fetal malformation

Many congenital malformations, especially urinary system malformations, are associated with oligohydramnios, such as congenital kidney deficiency, renal dysplasia, polycystic kidney and urethral stricture or atresia. The above-mentioned malformation leads to a decrease or no formation of urine, and the generated urine cannot be discharged or discharged, and there is no urine or oliguria, resulting in a decrease in amniotic fluid production, normal absorption of amniotic fluid, and finally oligohydramnios.

2. Placental insufficiency

The placenta is an organ exchanged between the fetus and the mother. The decrease in placental function can lead to a decrease in fetal blood volume, a decrease in fetal kidney blood supply, and finally a decrease in fetal urine production. The placental function is determined by the blood supply to the placenta, the maternal and child barrier of the placenta and the effective working area of the placenta. The reduction of placental function usually includes a decrease in the blood supply to the placenta, a decrease in the barrier function of the mother and child in the placenta, and a decrease in the effective area of the placenta.

The decline in blood supply to the placenta theoretically includes various reasons such as decreased blood volume of pregnant women, decreased blood pressure of pregnant women, and abnormal supply of blood vessels in the placenta. However, it is believed that the decline in blood volume of pregnant women is the main reason for the decline in blood supply to the placenta. The basic structure of the placenta for material exchange between the mother and the child is the maternal and child barrier of the placenta. The pathological mechanism of the placenta mother and child due to edema, thrombosis, fibrosis, calcification can lead to barrier function of the placenta mother and child, the material between the fetus and the mother The exchange declines and eventually leads to a decline in amniotic fluid production. In pregnant women with expired pregnancy, the total volume of the placenta is unchanged, but due to the above changes in the maternal and child barriers, the total effective placental material exchange area decreases, and finally the amniotic fluid is too small. It is common in clinical work that the small size and thin thickness of the placenta may be combined with the calcification fibrosis of the placenta mother surface. The basic placental mother-child barrier of this placenta may be normal or decreased, but the total effective area is reduced, and the placental function is severely incomplete. Placenta usually incorporates oligohydramnios and intrauterine growth retardation.

3. Drug effects

Many drugs can cause oligohydramnios. Common types are non-steroidal antipyretic analgesics and angiotensin-converting enzyme inhibitors. The most studied in non-steroidal antipyretic analgesics is indomethacin. Indomethacin can cause a decrease in uterus and placental circulation, a decrease in fetal blood volume and renal blood volume, and a decrease in urine production.

4. Expired pregnancy

When the pregnancy is overdue, the placental function is reduced, the perfusion is insufficient, and the fetus is dehydrated, resulting in less amniotic fluid. Some scholars believe that when the pregnancy is overdue, the fetus is over-mature, the sensitivity of its renal tubules to diuretic hormone is increased, and the amount of urine is too small, resulting in too little amniotic fluid. The incidence of oligohydramnios caused by overdue pregnancy is 20% to 30%.

5. Intrauterine growth retardation (IUGR)

Amniotic fluid is one of the characteristics of intrauterine growth retardation. Chronic hypoxia causes fetal blood circulation redistribution, mainly supplying the brain and heart, while renal blood flow is decreased, and fetal urine production is reduced, resulting in too little amniotic fluid.

6. Amniotic membrane disease

Electron microscopic observation showed that the amniotic epithelial layer became thinner when the amniotic fluid was too small, the epithelial cells were atrophied, the microvilli were short and thick, the tip was swollen, the number was small, and the squamous epithelial metaplasia occurred. The coarse-grained inner mesh and the Golgi complex were also reduced in the cells. The desmosome and hemides are reduced between the epithelial cells and the basement membrane. It is believed that the lack of amniotic fluid for some unknown reasons may be related to the lesion of the amniotic membrane itself.

(two) pathogenesis

During pregnancy, the amount and composition of amniotic fluid is not fixed, but is in a relatively stable dynamic process that is constantly generated and absorbed. When amniotic fluid production is reduced and/or amniotic fluid absorption is increased, amniotic fluid is produced when the amount of amniotic fluid produced is less than that of amniotic fluid. The mechanisms involved in amniotic fluid production and absorption are mainly fetal urine, fetal swallowing, fetal respiratory movement, fetal skin and fetal membranes (including amniotic membrane and chorion). The above mechanisms vary with gestational age. Fetal urine is the main mechanism of amniotic fluid production. Fetal swallowing is the main mechanism of amniotic fluid absorption, while other mechanisms may have the dual effects of amniotic fluid production and absorption.

an examination

Related inspection

Oxytocin stimulation test

Clinical manifestations:

Pregnant women often feel abdominal pain during fetal movement. The abdominal circumference and uterus height are lower than those of the same period of pregnancy. The uterus is highly sensitive. The slight stimulation can cause contractions. After labor, the pain is severe, the contractions are not coordinated, and the cervix is slow. The labor process is extended. If oligohydramnios occurs in the early stages of pregnancy, the membrane may adhere to the carcass, causing fetal malformations and even limb shortages. If it occurs in the middle and late pregnancy, the pressure around the uterus directly affects the fetus, which can easily cause musculoskeletal deformities, such as torticollis, curved back, hand and foot deformity. It has been confirmed that inhalation of a small amount of amniotic fluid during pregnancy contributes to the expansion and development of the fetal lung, and too little amniotic fluid can cause pulmonary hypoplasia. Some scholars have also suggested that pregnant women with expired pregnancy, intrauterine growth retardation, and pregnancy-induced hypertension have had fetal heart changes before formal labor, and there should be a possibility of oligohydramnios. Too little amniotic fluid is prone to fetal distress and neonatal asphyxia, increasing perinatal mortality. Shanghai's perinatal mortality rate, oligohydramnios is 5 times higher than normal pregnancy. Therefore, it is one of the key diseases.

Mainly based on clinical manifestations, B-ultrasound and direct measurement of amniotic fluid confirmed. Direct measurement of amniotic fluid, if the amniotic fluid <300ml is too little amniotic fluid when the membrane is broken, its nature is sticky, turbid, dark green. In addition, a plurality of round or oval nodules are often seen on the surface of the amnion, with a diameter of 2 to 4 mm, light grayish yellow, opaque, and containing stratified squamous epithelial cells and fetal fat. The biggest disadvantage of direct measurement is that it cannot be diagnosed early.

Differential diagnosis

During pregnancy, due to venous block or dystrophy, blood and blood run poorly, and abdominal pain occurs, called "pregnancy abdominal pain."

Maternal low back pain: According to the survey, 50%-75% of pregnant women will have low back pain, which is related to the special physiological changes of pregnant women during pregnancy, maternal low back pain, more attention to the details of pregnancy and postpartum life, some Dangerous movements exacerbate low back pain, so experts say that to prevent postpartum low back pain, it should start from pregnancy.

Pain in childbirth: Pain caused by uterine contractions will run through the entire delivery process. The contraction pain is mainly in the lower abdomen, sometimes on the inside of the two sides or on the spine. Most women feel that the contraction pain is similar to that of menstrual cramps, but it is more intense. When the fetus is about to be born, due to the expansion of the perineum and genital area, the mother will feel a burning sensation and strong pain in these parts. Finding a comfortable position and taking a deep breath in a relaxed state can alleviate the pain of childbirth.

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