Miscarriage is terminated at less than 28 weeks of gestation and the fetus weighs less than 1000g. A miscarriage that occurs before 12 weeks of gestation is called early miscarriage, and a miscarriage that occurs between 12 and less than 28 weeks of gestation is called late miscarriage. Miscarriage is divided into spontaneous abortion and induced abortion, and this section is limited to spontaneous abortion. The incidence of spontaneous abortion accounts for about 15% of all pregnancies, and most of them are early abortions.
I. Etiology: The causes of miscarriage are many, mainly in the following areas.
1, genetic defects in early spontaneous abortion, chromosomal abnormalities in the embryo accounted for 50-60%, mostly chromosomal number abnormalities, followed by chromosomal structure abnormalities. The number of abnormalities include trisomy, triploidy and X monosomy; structural abnormalities include chromosome breakage, inversion, deletion and translocation. The majority of embryos with chromosomal abnormalities are miscarried, but very few may continue to develop into a fetus, but some functional abnormalities or combined malformations may occur after birth. If the abortion, the pregnancy product is sometimes only an empty gestational sac or degenerated embryo.
2, environmental factors There are many external adverse factors affecting reproductive function, which can directly or indirectly cause damage to the embryo or fetus. Excessive exposure to certain harmful chemical substances (such as arsenic, lead, benzene, formaldehyde, chloroprene, ethylene oxide, etc.) and physical factors (such as radiation, noise and high temperature, etc.) can cause miscarriage.
3.Maternal factors
(1) systemic diseases: acute diseases during pregnancy, high fever can cause uterine contractions and miscarriage; bacterial toxins or viruses (herpes simplex virus, cytomegalovirus, etc.) enter the fetal blood circulation through the placenta, causing fetal death and miscarriage. In addition, pregnant women suffering from severe anemia or heart failure can cause fetal hypoxia, which may also cause miscarriage. If a pregnant woman suffers from chronic nephritis or hypertension, the placenta may become infarcted and cause miscarriage.
(2) Reproductive organ diseases: Pregnant women with uterine malformation (such as double uterus, longitudinal uterus and uterine dysplasia, etc.), pelvic tumors (such as uterine fibroids, etc.) can affect the growth and development of the fetus and lead to miscarriage. Loose inner cervical opening or severe cervical laceration can easily lead to late miscarriage due to premature rupture of fetal membranes
(3) endocrine disorders: insufficient luteal function often affects the meconium and placenta and miscarriage occurs. Those with low thyroid function may also miscarry due to embryonic dysplasia.
(4) Trauma: abdominal surgery during pregnancy, especially in early pregnancy, or trauma in mid-pregnancy can stimulate uterine contraction and cause miscarriage.
(4) Insufficient endocrine function of the placenta In early pregnancy, the corpus luteum of the ovary secretes progesterone, and the trophoblast of the placenta also gradually produces progesterone. After 8 weeks of pregnancy, the placenta gradually becomes the main place for producing progesterone. In addition to progesterone, the placenta also synthesizes other hormones such as β-chorionic gonadotropin, placental lactogen and estrogen. In early pregnancy, the value of the above-mentioned hormones decreases, making it difficult for the pregnancy to continue and resulting in miscarriage.
5. Immunological factors Pregnancy is like a homozygous transfer, there is a complex and special immunological relationship between the embryo and the mother, and this relationship keeps the embryo from being rejected. If the mother and child are not immune, it can cause the mother to reject the embryo and cause miscarriage. The main immunological factors involved are paternal histocompatibility antigens, fetal specific antigens, blood group antigens, maternal cellular immune dysregulation, maternal closed antibody deficiency during pregnancy and maternal cytotoxic antibody deficiency against paternal lymphocytes.
Pathology: In early miscarriage, most of the embryos die first, followed by bleeding of the bottom meconium, resulting in separation of the embryonic villi from the meconium layer, and the separated embryonic tissues are like foreign bodies, causing uterine contraction and expulsion. When the pregnancy is less than 8 weeks old, the placental villi are not yet mature and not firmly connected with the uterine metaplasm, so most of the aborted pregnancy products can be separated from the uterine wall and expelled intact with little bleeding.
During 8-12 weeks of gestation, the placental villi are well developed and firmly connected with the metaphragm. If abortion occurs at this time, the pregnancy products are often not easily separated and expelled completely, and some tissues often remain in the uterine cavity to affect the uterine contraction, resulting in more bleeding. After 12 weeks of gestation, the placenta has been fully formed, and abortion is often preceded by abdominal pain and then discharge of the fetus and placenta. Sometimes, due to repeated bleeding of the bottom mucosa, the clot wraps around the fetal mass, forming a blood-like fetal mass that stays in the uterine cavity. The hemoglobin is absorbed over time to form a flesh-like fetal mass, or fibrosis adheres to the uterine wall. Occasionally, the fetus is squeezed and forms a paper-like fetus, or calcified and forms a stone fetus.
Clinical manifestations: The main symptoms of miscarriage are vaginal bleeding and abdominal pain. Vaginal bleeding occurs in those who miscarry within 12 weeks of gestation and starts when the chorion separates from the meconium; the blood sinuses open and bleeding begins. When the embryo is completely separated and expelled, the bleeding stops due to uterine contractions. In early miscarriage, the whole process is accompanied by vaginal bleeding; in late miscarriage, the placenta has formed and the process of miscarriage is similar to that of early miscarriage, the placenta is expelled after the delivery of the fetus, and generally there is not much bleeding, characterized by abdominal pain first and then vaginal bleeding.
The abdominal pain during miscarriage is paroxysmal contraction-like pain, after vaginal bleeding occurs in early miscarriage; the separation of the embryo and the blood clots in the uterine cavity stimulate the uterus to contract and paroxysmal lower abdominal pain occurs, characterized by vaginal bleeding that often occurs before abdominal pain. In late miscarriage, there are paroxysmal uterine contractions followed by placental abruption, so vaginal bleeding occurs after abdominal pain. The size of the uterus, the dilatation of the cervical opening and the rupture of membranes during miscarriage vary according to the number of weeks of pregnancy and the miscarriage process.
Clinical types: The clinical types of miscarriage are actually the different stages of miscarriage development.
1. Premature miscarriage refers to a small amount of vaginal bleeding before 28 weeks of gestation, followed by paroxysmal lower abdominal pain or low back pain, the cervical opening is not opened during gynecological examination, the fetal membranes are not broken, the pregnancy products are not expelled, the size of the uterus is consistent with the number of weeks of menopause, and there is hope that the pregnancy will continue. After rest and treatment, if the bleeding stops and the lower abdominal pain disappears, the pregnancy can continue; if the vaginal bleeding increases or the lower abdominal pain intensifies, the pregnancy may develop into a refractory abortion.
2. Refractory miscarriage means that miscarriage is inevitable. It is developed from pre-eclampsia miscarriage, when the vaginal bleeding increases, the paroxysmal lower abdominal pain worsens or vaginal fluid (rupture of fetal membranes) appears. On gynecological examination, the cervical opening is dilated and sometimes embryonic tissue or the fetal sac is seen to be blocked in the cervical opening. The size of the uterus corresponds to the number of weeks of menopause or is slightly smaller.
3. Incomplete miscarriage refers to the development of inevitable miscarriage in which the pregnancy products are partially expelled from the body but some remain in the uterine cavity. The residual pregnancy products in the uterine cavity affect the contraction of the uterus, resulting in more than continuous uterine bleeding and even hemorrhagic shock due to excessive bleeding. On gynecological examination, the cervical opening is dilated and blood is constantly flowing from the cervical opening. It is fashionable to see placental tissue blocking the cervical opening or some of the pregnancy products have been expelled in the vagina, while some remain in the uterine cavity. Usually the uterus is smaller than the number of weeks of menopause.
4.Complete miscarriage means that all pregnancy products are expelled, vaginal bleeding gradually stops and abdominal pain gradually disappears. The cervical opening is closed and the uterus is close to the normal size during gynecological examination.
In addition, there are three special cases of miscarriage.
1. Induced miscarriage means that the embryo or fetus has died and remained in the uterine cavity before being expelled naturally. After the death of the embryo or fetus, the uterus no longer enlarges but shrinks, and the early pregnancy reaction disappears. If the pregnancy has reached the middle stage, the pregnant woman’s abdomen does not increase in size and the fetal movement disappears. The cervical opening is not opened, the uterus is smaller than the number of weeks of menopause, and the texture is not soft. The fetal heart is not heard.
2.Habitual miscarriage Refers to the occurrence of spontaneous miscarriage for 3 times or more in a row. In recent years, recurrent spontaneous miscarriage is commonly used internationally instead of habitual miscarriage. Each miscarriage occurs in the same month of pregnancy, and its clinical course is the same as general miscarriage. The causes of early miscarriage are often luteal insufficiency, hypothyroidism, chromosomal abnormalities, etc. The most common causes of late miscarriage are relaxation of the endocervix, uterine malformation, and uterine fibroids. In cases of loose endocervical opening, the fetus grows, the amniotic fluid increases, the pressure in the uterine cavity increases, the fetal sac protrudes toward the endocervical opening, and the cervical canal gradually shortens and dilates after pregnancy, often in the middle of pregnancy. Once the fetal membranes rupture, the fetus is discharged immediately.
3.Miscarriage infection During miscarriage, if the vaginal bleeding is too long, there is tissue residue in the uterine cavity or illegal abortion, it may cause infection in the uterine cavity, and in serious cases, the infection may extend to the pelvic cavity, abdominal cavity and even the whole body, complicating pelvic inflammation, peritonitis, sepsis and infectious shock, called miscarriage infection.
Diagnosis: It is generally not difficult to diagnose miscarriage. According to the medical history and clinical manifestations can mostly confirm the diagnosis, only a few need to conduct auxiliary examinations. After the diagnosis of miscarriage is confirmed, the clinical type of miscarriage should also be determined and the treatment method should be decided.
The patient should be asked about the history of menopause and recurrent miscarriage, whether there is early pregnancy reaction, vaginal bleeding, the amount of vaginal bleeding and its duration, whether there is abdominal pain, the location, nature and degree of abdominal pain, and whether there is watery vaginal discharge, the color and amount of vaginal discharge and whether there is odor, and whether there is discharge of pregnancy products, etc.
Observe the general condition of the patient, whether there is anemia, and measure the body temperature, blood pressure and pulse rate. Under sterilized conditions, gynecological examination should be carried out, paying attention to whether the cervical opening is dilated, whether the amniotic sac is bulging, whether there are pregnancy products blocked in the cervical opening; whether the size of the uterus matches the number of weeks of menopause, and whether there is pressure pain, etc. It should also be checked for bilateral adnexal masses, thickening and pressure pain. The examination should be done gently, especially for those who are suspected to have preterm abortion.
3.Auxiliary examination For those who have difficulty in diagnosis, necessary auxiliary examination can be used.
(l) B-type ultrasound imaging: it is widely used at present. It has practical value for differential diagnosis and determining the type of miscarriage. For suspected pre-eclampsia miscarriage, it can determine whether the embryo or fetus is alive according to the shape of the gestational sac, the presence or absence of fetal heart reflex and fetal movement, in order to guide the correct treatment method. Incomplete miscarriage and retained miscarriage can be determined with the help of B-type ultrasonography.
(2) Pregnancy test: using immunological methods, in recent years the clinical use of test paper method, is meaningful for the diagnosis of pregnancy. In order to further understand the prognosis of miscarriage, radioimmunoassay or enzyme-linked immunosorbent assay is mostly used for quantitative determination of HCG.
(3) Other hormone determination: other hormones mainly include the determination of blood progesterone, which can assist in determining the prognosis of preterm abortion.
Differential diagnosis: First, the type of miscarriage should be identified. Early miscarriage should be distinguished from ectopic pregnancy and gravidity, and also from dysfunctional uterine bleeding and uterine fibroids.
7. Treatment: Miscarriage is a common disease in obstetrics and gynecology, and once the symptoms of miscarriage occur, appropriate treatment should be carried out in a timely manner according to different types of miscarriage.
1, pre-eclampsia abortion should be bed rest, abstain from sexual intercourse, vaginal examination operation should be gentle, if necessary, give sedatives that are less harmful to the fetus. Progesterone 20mg daily intramuscular injection has a fetal preservation effect on patients with luteal insufficiency. Secondly, vitamin E and small doses of thyroid powder (for patients with hypothyroidism) can also be applied. In addition, psychological treatment for patients with pre-eclampsia is also important to make them emotionally stable and increase their confidence. If the symptoms are not relieved or worsened after two weeks of treatment, it is suggested that the embryo may be developing abnormally, so B-type ultrasound examination and HCG determination should be performed to determine the embryo status and give appropriate treatment, including termination of pregnancy.
2. Inevitable miscarriage Once diagnosed, the embryo and placental tissue should be completely expelled as soon as possible. For early abortion, negative pressure aspiration should be performed promptly, and the pregnancy products should be carefully examined and sent for pathological examination. For late miscarriage, because the uterus is large, suction or scraping the uterus is difficult, 10 units of uterine contraction can be added to 5% glucose solution 5OOml intravenously to promote uterine contraction. When the fetus and the placenta are expelled, it is necessary to check whether it is complete and scrape the uterus if necessary to remove the residual pregnancy products in the uterine cavity.
3, incomplete abortion Once diagnosed, aspiration or curettage should be performed promptly to remove residual tissue in the uterine cavity. For those who bleed a lot and have shock, blood and fluids should be transfused at the same time, and for those who bleed for a long time, antibiotics should be given to prevent infection.
4.Complete miscarriage If there is no sign of infection, no special treatment is usually needed.
5. Retained miscarriage is more difficult to handle. Because the placental tissue has timing and is closely adhered to the uterine wall, it is difficult to scrape the uterus. If the retention time is too long, coagulation dysfunction may occur, resulting in DIC and serious bleeding. Before treatment, blood routine, clotting time, platelet count, blood fibrinogen, prothrombin time, clot contraction test and plasma fisetin paraclotting test (3P test) should be checked and blood transfusion should be prepared.
If coagulation is normal, oral ethinyl estradiol 1mg twice daily or oral hexestrol 5mg 3 times daily for 5 days to improve the sensitivity of the uterine muscle to contractin. If the uterus is less than 12 gestational weeks, scraping is feasible and contraction is injected to reduce bleeding. If the placenta is mechanized and adheres tightly to the uterine wall, special care should be taken to prevent perforation, and if the uterus cannot be scraped at once, the uterus can be scraped again after 5-7 days. If the uterus is larger than 12 weeks of gestation, intravenous injection of uterine contraction (5-10 units in 5% glucose solution) should be given, and prostaglandin or estradiol can also be used to induce labor to promote the expulsion of the fetus and placenta. If coagulation dysfunction, heparin, fibrinogen and fresh blood transfusion should be used as soon as possible, and then induce labor or scrape after the coagulation function improves.
Women with a history of habitual miscarriage should undergo necessary examinations before pregnancy, including ovarian function examination, chromosome examination and blood type identification of both spouses and semen examination of their husbands, and detailed examination of the reproductive tract of the woman, including the presence of uterine fibroids and uterine adhesions, and hysterosalpingography and hysteroscopy to determine whether the uterus is deformed and diseased, and to check whether there is endocervical The cause should be identified and, if corrected, treated. If the cause is identified and can be corrected, it should be treated before pregnancy. In women with unexplained habitual abortion, when there are signs of pregnancy, progesterone can be administered as luteinizing hormone, 10-2Omg daily or HCG300OU every other day.
After pregnancy is confirmed, continue to administer the drug until 10 weeks of gestation or beyond the month of previous miscarriage, and instruct her to rest in bed, abstain from sexual intercourse, take vitamin E supplements and give psychotherapy to relieve her mental tension and stabilize her emotions. If the endocervical opening is loose, endocervical repair should be performed before pregnancy. If you are pregnant, it is better to perform endocervical ring ligation at 14-16 weeks of gestation, follow up regularly after the operation, stay in hospital in advance, and remove the sutures before labor is initiated.
7.Miscarriage infection Miscarriage infection is mostly incomplete miscarriage combined with infection. The principle of treatment should be to actively control the infection, if the vaginal bleeding is not much, apply broad-spectrum antibiotics for 2-3 days, and then scrape the uterus after the infection is controlled to remove the residual tissue in the uterine cavity to stop the bleeding. If there is a lot of vaginal bleeding, use intravenous broad-spectrum antibiotics and blood transfusion at the same time, use oval forceps to clip out the residual tissue in the uterine cavity to reduce bleeding, do not use a scraper to scratch the uterine cavity comprehensively to avoid spreading infection.
Continue to apply antibiotics after the operation and wait for the infection to be controlled before performing thorough scraping. If infectious shock has been combined, shock should be actively corrected. If the infection is serious or there is abscess formation in the abdominal or pelvic cavity, surgical drainage should be performed, and if necessary, the uterus should be removed.