Placenta previa

　　It is not yet clear, and it may be related to the following factors.

　　1. Endometrial lesions in the uterine body such as puerperal infection, multiple deliveries, multiple abortions, and cesarean sections, which can cause endometritis or endometrial damage, leading to incomplete growth of the endometrial blood vessels. When the fertilized egg implants, the blood supply is insufficient. To obtain sufficient nutrition, the placental area expands and extends to the lower segment of the uterus.

　　2. Large placental area such as the placental area of twins is larger than that of singletons and reaches the lower segment of the uterus. The incidence of placenta previa in twins is twice that of singletons.

　　3. Abnormal placenta such as accessory placenta, the main placenta is in the uterine body, while the accessory placenta can reach the lower segment of the uterus near the internal os of the cervix.

　　4. Delayed development of the trophoblast of the fertilized egg When the fertilized egg reaches the uterine cavity, it has not yet developed to the stage where it can implant and continues to migrate downward into the lower segment of the uterus, where it grows and develops into placenta previa.

　　Complications of placenta previa:

　　1、Postpartum hemorrhage: After delivery, due to the thin muscle tissue and poor contraction force of the lower segment of the uterus, the placenta attached to this area is not easy to tighten and close the blood sinus temporarily after detachment, so postpartum hemorrhage often occurs.

　　2、Implantation placenta: Due to reasons such as poor development of the decidua, the placental villi can implant into the uterine muscle layer, causing incomplete placental detachment and massive bleeding.

　　3、Puerperal infection: The placental detachment surface of placenta previa is close to the external os of the cervix, making it easy for bacteria to enter the placental detachment surface from the vagina. Most women are anemic and physically weak, making them prone to infection.

　　In the late stage of pregnancy or during labor, the main symptom of placenta previa is the occurrence of painless, repeated vaginal bleeding without any cause, which may occur around the 20th week of pregnancy. The bleeding is due to the gradual extension of the lower segment of the uterus during the late stage of pregnancy or after labor, the disappearance of the cervical canal, or the expansion of the cervix, while the placenta attached to the lower segment of the uterus or the internal os of the cervix cannot extend correspondingly, causing the placenta in the anterior part to be stripped from its attachment, leading to the rupture of blood sinuses and bleeding. The amount of the first bleeding is generally not much, and the bleeding can stop temporarily after the blood at the stripping site coagulates, and occasionally there are cases with a large amount of the first bleeding. With the continuous extension of the lower segment of the uterus, bleeding often occurs repeatedly and the amount of bleeding also increases. The timing of the occurrence of vaginal bleeding, the frequency of recurrence, and the amount of bleeding are closely related to the type of placenta previa. Complete placenta previa often has an early onset of bleeding, about 28 weeks of pregnancy, frequent recurrence of bleeding, and a large amount of bleeding, sometimes a large amount of bleeding at one time can cause the patient to fall into a shock state; marginal placenta previa has a later onset of bleeding, mostly around 37-40 weeks of pregnancy or during labor, and the amount of bleeding is also less; partial placenta previa has an intermediate time and amount of bleeding between the two. For patients with partial or marginal placenta previa, rupture of the amniotic membrane is beneficial for the pressure of the presenting part on the placenta, and if the presenting part can quickly descend after rupture, directly pressing the placenta, bleeding can stop.

　　Due to repeated multiple or large amounts of vaginal bleeding, patients may develop anemia, the degree of anemia being proportional to the amount of bleeding. Severe bleeding can lead to shock, and the fetus may experience hypoxia, distress, and even death.

　　1.Avoid lifting heavy objects: In the middle and later stages of pregnancy, pay more attention to the details of daily life. It is not advisable to lift heavy objects or exert force on the abdomen to avoid danger.
　　2.Suspend sexual activity as appropriate: If there are bleeding symptoms or you are in the later stages of pregnancy, it is not advisable to have sexual intercourse. In addition, patients with mild placenta previa should also avoid too intense sexual activity or actions that compress the abdomen.
　　3.Seek medical attention immediately if there is bleeding: When there are bleeding symptoms, seek medical attention immediately regardless of the amount of blood. If you meet a new prenatal check-up doctor, you should also actively inform them of the placenta previa issue.
　　4.Do not overexert: Pregnant women with high-risk pregnancies should rest more and avoid overexertion to affect the smooth progress of pregnancy and childbirth.
　　5.Pay attention to fetal movement: Pay attention to the normalcy of fetal movement daily. If you feel that the fetal movement is significantly reduced, you should seek medical attention as soon as possible.
　　6.Choose a suitable prenatal check-up hospital: If the patient has placenta previa of the third or fourth grade, it is best to choose a large hospital or medical center for prenatal check-ups, so that immediate treatment can be provided in case of preterm labor or massive bleeding.
　　7.Do not overexert: Excessive exercise may also trigger bleeding in placenta previa or other symptoms, therefore, pregnant women of this type should not engage in too intense exercise.

　　Vaginal examination

　　Generally, only vaginal examination and palpation of the fornix should be performed, and cervical canal palpation should not be performed to avoid causing placental detachment at the attachment site, which may lead to massive bleeding. In the case of complete placenta previa, it may even be life-threatening. Vaginal examination is indicated before termination of pregnancy to clarify the diagnosis and determine the mode of delivery. It must be performed under conditions of fluid infusion, blood transfusion, and surgery. If the diagnosis is clear or there is excessive bleeding, vaginal examination should not be performed again. In recent years, B-ultrasound examination has been widely used, and vaginal examination is rarely performed.

　　Examination method: After strictly disinfecting the vulva, use a vaginal speculum for examination to observe the presence of varicose veins in the vaginal wall, cervical polyps, cervical cancer, or other lesions that may cause bleeding. After the examination, gently palpate the vaginal fornix around the cervix with one hand's index and middle fingers. If the fetal presentation can be clearly felt, placenta previa can be ruled out. If there is a thick soft tissue (placenta) between the fingers and the fetal presentation, consider it as placenta previa. If the cervical os has partially dilated without active bleeding, the index finger can be gently inserted into the cervix to check for spongy tissue (placenta), which is easily crumbled when touched by blood clots. Pay attention to the relationship between the placenta edge and the cervical os to determine the type of placenta previa. If the amniotic membrane is touched and it is decided to rupture it, the amniotic membrane can be pierced. The operation must be gentle, and the placental tissue should not be further separated from its attachment to avoid massive bleeding. If massive bleeding occurs during the examination, the examination should be immediately stopped, and cesarean section should be performed to end the delivery.

　　Ultrasonic examination

　　B-ultrasound tomography can clearly show the position of the uterine wall, the presenting part of the fetus, the placenta, and the cervix, and further clarify the type of placenta previa based on the relationship between the edge of the placenta and the internal os of the cervix. The accuracy rate of placenta localization is over 95%, and it can be repeated. In recent years, it has been widely used in China and abroad, basically replacing other methods such as radioactive isotope scanning localization and indirect placental angiography.

　　When diagnosing placenta previa with B-ultrasound, attention should be paid to the gestational age, as the placenta occupies half of the uterine cavity in the middle trimester of pregnancy. Therefore, there is a higher chance that the placenta is near the internal os of the cervix or covers the internal os. By the late stage of pregnancy, the area occupied by the placenta in the uterine cavity decreases to 1/3 or 1/4; at the same time, the formation and extension of the lower uterine segment increase the distance between the internal os of the cervix and the edge of the placenta. Therefore, the placenta that originally seemed to be in the lower uterine segment can change to a normal position as the body of the uterus rises. Therefore, if a low-lying placenta is found in the middle trimester B-ultrasound examination, do not make an early diagnosis of placenta previa, and follow up regularly. In general, no diagnosis of placenta previa is made before 34 weeks of gestation if there are no symptoms of vaginal bleeding.

　　Postpartum examination of the placenta and amniotic membrane

　　For patients with preterm bleeding, a careful examination of the placenta delivered after birth should be conducted to verify the diagnosis. The placenta in the prefrontal position has blackish purple old blood clots attached. If the distance between the rupture of the amniotic membrane and the edge of the placenta is

　　The main distinction for bleeding in the late stage of pregnancy should be with placental abruption; other causes of preterm bleeding, such as rupture of the chorionic plate anterior vessels and placental margin bleeding.

　  Patients with placenta previa should eat:

　　1. Adopt a diet of eating less but more frequently. The closer to the time of delivery, the more iron should be taken in. However, at this time, the gastrointestinal tract is compressed by the uterus, and eating too much at one time can cause bloating and is more likely to cause constipation or diarrhea. Therefore, it is better to eat less but more frequently, about 4-5 times a day. Focus on lunch, reduce the amount of staple food, increase the nutrition of side dishes, and eat more dairy products, fresh vegetables, etc., to prevent constipation.

　　2. The seasoning should be light. For pregnant women in the later stages of pregnancy, the food should be seasoned as lightly as possible, with less salt and soy sauce, and do not place pickles and soy sauce on the table. If the taste is not sufficient and it affects appetite, some sugar and vinegar can be added inside.

　　3. The diet should be tailored to the specific situation of the pregnant woman. During prenatal examinations, the pregnant woman can consult a doctor to understand whether the fetus is developing well, whether it is too large or too small, and at the same time, consider her own body size, workload, and family economic conditions, etc., to formulate an appropriate diet plan.

　　4. In the later stages of pregnancy, gestosis and other complications of pregnancy are more likely to occur. The diet should be adjusted according to the nature and severity of the complications. For example, if there is a significant increase in blood pressure, severe edema, and the appearance of proteinuria, the intake of protein and salt should be limited. Under the guidance of a doctor, a 'treatment diet menu' should be formulated.

　　5. Choose easily digestible high-quality proteins such as fish and other meats; eat less animal fat.

　　6. Supplementing vitamins and minerals can help repair the liver and kidneys.

　　Due to the increase in the secretion of estrogen and progesterone during pregnancy, as well as the destruction by hepatitis virus, it causes the disorder of folic acid metabolism.

　　7. Eat more animal liver, kidneys, and vegetables rich in folic acid.

　　8. When suffering from hepatitis, pregnant mothers are also prone to lack of vitamin C, and should intake 80 to 100 milligrams of vitamin C per day.

　　9. For mothers with kidney problems, they also need to control salt and limit potassium intake, usually no more than 3 grams of salt per day.

　　Patients with placenta previa should avoid eating.

　　Hawthorn: Hawthorn promotes blood circulation and removes blood stasis, has a certain contractile effect on the uterus, and should be eaten in small quantities during the early stage of pregnancy. Pregnant women with a history of miscarriage or those with signs of miscarriage should avoid eating hawthorn, and this also applies to hawthorn products.

　　Lychee and Longan: From a traditional Chinese medicine perspective, after women get pregnant, their constitution is generally hot, and yin and blood are often insufficient. At this time, some hot fruits such as lychee and longan should be eaten in moderation, otherwise, it is easy to produce symptoms of上火 such as constipation and ulcers on the tongue and lips, especially for pregnant women with threatened miscarriage, who should be more cautious because hot fruits are more likely to cause restlessness of the fetus.

　　Citrus: There are many varieties of citrus, including sweet oranges, southern mandarins, seedless honey mandarins, and pommelos. They all have the common advantages of being rich in nutrients and being useful all over. Their juice is rich in citric acid, amino acids, carbohydrates, fats, various vitamins, calcium, phosphorus, iron, and other nutritional ingredients, which are foods that pregnant women like to eat. However, although citrus is delicious, it should not be eaten in large quantities. Because citrus is warm and sweet, it nourishes the yang and vitalizes the body, and excessive intake can be counterproductive to the body, causing dryness and heat, leading to oral inflammation, periodontitis, pharyngitis, and other conditions. Pregnant women should not eat more than 3 citrus fruits a day, with a total weight of no more than 250 grams.

　　Persimmon: Persimmon is cold in nature, with the effects of clearing heat, moistening the lungs, generating moisture, quenching thirst, suppressing cough, and removing phlegm. It is suitable for treating hypertension, chronic bronchitis, atherosclerosis, hemorrhoids with bleeding, constipation, and other symptoms. Its nutritional and medicinal value is suitable for pregnant women to eat in moderation. Especially for pregnant women with pregnancy-induced hypertension syndrome, they can 'get two benefits from one eating'. The calyx and leaves of persimmon are also used in traditional Chinese medicine. The calyx can relieve reversed gas, stop nausea, and treat hiccups and belching. Persimmon leaves have the effects of antibacterial and anti-inflammatory, hemostasis and hypotension, and are commonly used folk medicine. Although persimmon has good nutritional and medical effects, it also has its shortcomings. Persimmon has a bitter taste, and eating too much will make the mouth and tongue numb, with a strong astringent effect, causing constipation. When encountering acid, it can coagulate into lumps, and when combined with protein, it will produce precipitation. Therefore, eating persimmon should be done in moderation, and one per meal is recommended. Therefore, pregnant women can eat persimmon but not too much.

　　Kiwi: Kiwi is rich in nutrients and is known as the 'King of Fruits'. Pregnant mothers who love beauty can eat more kiwi without worrying about freckles 'invading' their fair faces after pregnancy. Kiwi contains abundant vitamin C, which keeps your skin fair. Moreover, although kiwi is good, not everyone is suitable for it. Due to its cold nature, people with weak spleen and stomach should eat it with caution, and those with frequent diarrhea and frequent urination should not eat it. It is more appropriate to eat it 1-3 hours after meals, and not on an empty stomach. Pregnant women with threatened miscarriage should never eat kiwi.

　　Pineapple, banana, muscat grape, pomegranate, and apricot: These fruits should be eaten in moderation. Pineapple, banana, muscat grape, and other fruits have a high sugar content. Pregnant women who are overweight or have a family history of diabetes should eat less to avoid excessive sugar intake. If the pregnant woman has anemia, she should also eat less pomegranate and apricot.

　　Expectant treatment: If the pregnancy is less than 36 weeks, the fetus weighs less than 2300g, the amount of vaginal bleeding is not much, the general condition of the pregnant woman is good, and the fetus survives, expectant treatment can be adopted.
　　(1) Absolute bed rest, sedatives such as Lumyuna or Anxiol can be given orally.
　　(2) Inhibit uterine contraction, Salbutamol 2.4-4.8mg, once every 4-6 hours, after the uterine contraction stops, maintain the dose.
　　(3) Correct anemia, oral ferrous sulfate, and transfuse blood if necessary.
　　(4) Antimicrobial agents (penicillin, ceftriaxone) to prevent infection.
　　(5) Injection or intravenous injection of dexamethasone to promote fetal lung maturation.
　　(6) Strictly observe the condition, and carry out relevant auxiliary examinations at the same time, such as B-ultrasound examination, fetal maturity examination, etc., if there is a large amount of bleeding or repeated bleeding, consider terminating pregnancy according to circumstances.
　　Termination of pregnancy: Appropriate for severe hemorrhagic shock at admission, severe hemorrhagic shock during the expectant treatment of placenta previa, or repeated bleeding close to the expected delivery date, or a large amount of bleeding during labor, all require active measures to terminate pregnancy. There are two ways to terminate pregnancy:
　　(1) Cesarean section (the main means of treating placenta previa) Before surgery, it is necessary to actively correct shock, infuse fluid and blood to supplement blood volume, and pay attention to the selection of uterine incision position during surgery, trying to avoid the placenta.
　　(2) Vaginal delivery Vaginal delivery is a method of stopping bleeding by pressing the placenta with the presenting part of the fetus. This method is only suitable for marginal placenta previa and cephalic presentation of the fetus. Bleeding occurs during labor, but the amount of blood is not much, the condition of the mother is generally good, the progress of labor is smooth, and it is estimated that delivery can be completed in a short time. After deciding on vaginal delivery, surgical amniotomy is performed, the head of the fetus descends and presses the placenta to stop bleeding, which can also promote uterine contraction and accelerate delivery. This method is more effective for women who have given birth before.