What Are the Most Common Reasons for Miscarriage?

Abortion that occurs in a natural state (caused by non-human purposes) is called spontaneous abortion. The incidence of spontaneous abortion is about 15% in all clinically confirmed pregnancies. Abortion that occurs before 12 weeks is defined as early miscarriage, and abortion between 12 weeks and less than 28 weeks of pregnancy is defined as late abortion. It is estimated that about 75% of all human pregnancies end in spontaneous abortion. Among them, most of the embryos stopped developing soon after implantation, only manifested as excessive menstruation or delayed menstruation, that is, early pregnancy abortion.

Basic Information

English name: spontaneous abortion
Visiting department: Obstetrics and Gynecology

Common causes: More than half of early abortions are caused by embryo chromosomal abnormalities
Common symptoms: Vaginal bleeding and abdominal pain after pregnancy

Causes of spontaneous abortion

More than 80% of miscarriages occur within 12 weeks of gestation, and the abortion rate subsequently decreases rapidly. At least half of the early abortions are caused by embryo chromosomal abnormalities. The risk of spontaneous abortion increases with the number of births and the age of the parents. Common causes of miscarriage include:

Chromosomal abnormality

Including couple chromosomal abnormalities and embryo chromosomal abnormalities. Common couple chromosomal abnormalities are balanced translocation, Robertson translocation and so on. Embryo chromosomal abnormalities have the most triploids, followed by polyploids, X monomers, autosomal monomers, chromosomal equilibrium translocations, deletions, chimeras, inversions, and overlaps. The incidence of chromosomal abnormalities in couples with recurrent miscarriage was 4%, compared with 0.2% in the normal population. The ratio of maternal to paternal origin was 3: 1. Embryo chromosomal abnormalities are the main cause in a single spontaneous abortion, and the incidence of embryo chromosomal abnormalities decreases with the number of abortions.

2. Maternal endocrine disorders

(1) Luteal dysfunction accounts for 23% to 60%, and the basal body temperature is biphasic, but the high temperature phase is less than 11 days, or the difference between high and low temperature is less than 0.3 ° C. Endometrial biopsy shows that the secretory response is at least 2 days behind, and the progesterone in the luteal phase is low 15 ng / ml caused a poor decidual reaction in pregnancy, luteal function test showed insufficient in 2 to 3 cycles before it can be included in the diagnosis, luteal insufficiency affects pregnancy egg implantation.

(2) High concentrations of luteinizing hormone, hyperandrogens, and hyperinsulinemia in polycystic ovary syndrome reduce egg quality and endometrial receptivity, which can easily lead to abortion.

(3) Prolactin receptors are present in luteal cells of hyperprolactinemia . Hyperprolactin inhibits luteinization and steroid hormones of granulocytes, leading to luteal insufficiency and decreased egg quality.

(4) Thyroid disease Hypothyroidism is associated with recurrent spontaneous abortion.

(5) Diabetes with subclinical or satisfactory control will not cause abortion, and the natural abortion rate of uncontrolled insulin-dependent diabetes mellitus will increase.

3. Maternal reproductive tract abnormalities

(1) Uterine malformations include single horn uterus, double horn uterus, double uterus and mediastinum. Among them, incomplete uterine mediastinum is most likely to cause miscarriage and premature birth. Mainly due to poor endometrial development of the mediastinum, insensitivity to steroid hormones, poor blood supply.

(2) Asherman syndrome reduces the uterine volume and decreases the response to steroid hormones.

(3) Cervical insufficiency causes late-term abortion and premature delivery, which is the main cause of abortion in the second trimester.

(4) Uterine fibroids submucosal fibroids and intermuscular fibroids larger than 5 cm are related to abortion.

4. Reproductive tract infection

Patients with bacterial vaginosis have an increased incidence of miscarriage and premature delivery in late pregnancy. Endometritis or cervical inflammation caused by chlamydia trachomatis and mycoplasma urealyticum can cause abortion.

5. Other

An unhealthy lifestyle is associated with miscarriage. Some scholars have reported that women who smoke more than 14 cigarettes a day have twice the risk of miscarriage compared to the control group. The effects of alcohol, excessive caffeine consumption, and environmental factors such as organic solvents and poisons. ^[1]

Clinical manifestations of spontaneous abortion

Mainly after diagnosis of vaginal bleeding and abdominal pain. Clinical types can be divided into:

Threatened abortion

Predominantly before 8 weeks of pregnancy, a small amount of vaginal bleeding first appears, followed by paroxysmal lower abdominal pain or low back pain. Gynecological examination did not open the cervix, the fetal membrane was not broken, the pregnancy product was not discharged, and the size of the uterus was consistent with the number of menopause weeks. After rest and treatment, some patients improved. If vaginal bleeding increases or lower abdominal pain worsens, it can inevitably lead to miscarriage.

2. Inevitable miscarriage

Refers to abortion is unavoidable. It develops from threatened abortion. At this time, the amount of vaginal bleeding increases, paroxysmal lower abdominal pain increases or vaginal fluid (rupture of the membrane) appears. Gynecological examination of the cervical mouth has been expanded, sometimes visible embryonic tissue or fetal sac blocked in the cervical mouth, the size of the uterus in line with the number of menopause or slightly smaller. At this time, the contractions gradually intensified, and the pregnancy tissue may continue to be partially or completely excreted, and it may develop into incomplete or complete abortion.

3. Incomplete abortion

It means that the pregnancy product has been partially excreted from the body, and some remain in the uterine cavity, which is caused by the inevitable development of abortion. Some pregnancy products in the uterine cavity affect the uterine contraction, causing the uterine bleeding to continue, and even hemorrhagic shock due to excessive bleeding. Gynecological examination The cervical opening has been dilated, and blood is constantly flowing from the cervical opening. It is fashionable to see that placental tissue is blocked in the cervical opening or some pregnancy products have been discharged into the vagina, while some remain in the uterine cavity. Generally the uterus is less than the number of weeks of menopause.

4. Complete abortion

It means that all pregnancy products have been discharged, vaginal bleeding has gradually stopped, and abdominal pain has gradually disappeared. Gynecological examination The cervix was closed and the uterus was close to normal size.

5. Miscarriage

Refers to an embryo or fetus that has died and remains in the uterine cavity and has not been naturally excreted. It is also called embryonic termination when it occurs early in pregnancy. After the death of the embryo or fetus, the uterus no longer grows but shrinks, and the early pregnancy response disappears. If the pregnancy has reached mid-term, the abdomen of the pregnant woman does not increase and the fetal movement disappears. Gynecological examination did not open the cervix, the uterus was smaller than the number of menopause weeks, and the texture was not soft. Undetected fetal heart.

6. Abortion infection

In the process of abortion, if the vaginal bleeding time is too long, there are tissues remaining in the uterine cavity or illegal abortion, etc., it may cause intrauterine infection. In severe cases, the infection can spread to the pelvic cavity, abdominal cavity and even the whole body, and pelvic inflammation, peritonitis, and sepsis And septic shock, etc., called abortion infection.

Spontaneous abortion check

Pregnancy tests and ultrasounds can be performed to assist diagnosis.

Diagnosis of spontaneous abortion

The diagnosis can be made based on medical history and clinical manifestations, but sometimes it needs to be combined with auxiliary examination to confirm the diagnosis. Different types of abortion have different treatment principles, so they should be determined at the same time during diagnosis.

Medical history

Ask if you have a history of menopause, early pregnancy reactions and when they occur, the amount and duration of vaginal bleeding, the relationship with abdominal pain, the location and nature of the abdominal pain, and whether the pregnancy tissues have been excreted. Knowing if you have fever or vaginal secretions can help diagnose miscarriage. Asking for a history of recurrent miscarriages can help diagnose recurrent miscarriages.

2. Physical examination

Measure body temperature, pulse, respiration, and blood pressure for signs of anemia and acute infection. When examining the abdomen, pay attention to the presence of tenderness, rebound pain, muscle tension, and dullness in the abdomen. Gynecological examination after vulvar disinfection, to know whether the cervix is dilated, whether there is pregnancy tissue blocking the cervix or amniotic swell, whether the uterus is tender, whether the size of the uterus is consistent with the time of menopause, and whether there is tenderness, thickening or mass in the double accessories. Suspected threatened abortion, the operation should be gentle.

3. Related inspections

Diagnose with pregnancy test, ultrasound, etc.

Differential diagnosis of spontaneous abortion

First distinguish the type of miscarriage. It also needs to be distinguished from ectopic pregnancy, hydatidiform mole, dysfunctional uterine bleeding, pelvic inflammatory disease, and acute appendicitis.

Spontaneous abortion treatment

After the diagnosis of abortion is confirmed, it should be handled according to its clinical type.

Threatened abortion

Bed rest, taboo sex life. For patients with luteal dysfunction, progesterone treatment can be applied. During the treatment, observe the patient's symptoms and changes in test results, and if necessary, perform ultrasound examination to confirm the fetal development. Ectopic pregnancy (ectopic pregnancy) should be ruled out before fertility management.

2. Inevitable abortion and incomplete abortion

Once diagnosed, the embryo and placental tissue should be completely discharged as soon as possible. When inevitable miscarriage or incomplete abortion occurs in early pregnancy, negative pressure aspiration should be performed in time. Check abortion tissue carefully and send for pathological examination. Late abortion needs to promote uterine contractions. After the fetus and placenta are completely delivered, check whether the placental placenta is complete, and cure the uterus if necessary to remove the remaining pregnancy products in the uterine cavity. For those with excessive vaginal bleeding, complete laboratory tests, transfusions, anti-shock treatments if necessary, and those with longer bleeding periods should be given antibiotics to prevent infection.

3. Complete abortion

If there are no signs of infection, there is generally no need to deal with feasible ultrasound examinations to determine whether there are residues in the uterine cavity.

4. Miscarriage

Abortion is usually performed. If the embryo stops developing for a long time, the pregnancy tissue mechanization and the uterine wall are tightly adhered, which may cause surgical difficulties and may cause major bleeding due to abnormal coagulation function. Before treatment, blood routine, coagulation time, platelet count, etc. should be checked and blood transfusion should be prepared.

5. Abortion infection

Most often occur in the treatment of incomplete abortion combined with infection. The principle should be to actively control the infection. If vaginal bleeding is not used, broad-spectrum intravenous antibiotics should be used. After the infection is controlled, complete uterine evacuation. If septic shock has been combined, the shock should be corrected actively. If the infection is severe or the abdomen or abscess is formed, surgical drainage should be performed to remove the uterus if necessary. ^[2]

Prognosis of spontaneous abortion

The probability of recurrent miscarriages increases with the number of previous miscarriages. In patients without previous live births, the risk of spontaneous abortion after two spontaneous abortions is about 35%. When the patient had a live birth, the risk of recurrence of abortion was about 32% after three spontaneous abortions.

Prevention of spontaneous abortion

Law of life

Adjust your work and rest time, exercise properly, and ensure that you sleep for 8 hours a day. Avoid situations such as staying up late and irregular schedules. Adjust working conditions to avoid excessive working pressure.

2. Keep your mood comfortable

3. Pay attention to personal hygiene

Change your clothes and take a bath frequently. Pay special attention to clean the genitals to prevent germ infection. Clothing should be wide and the belt should not be tightened.

4. Choose the right diet

Food should be easy to digest. Especially choose foods rich in various vitamins and trace elements, such as various vegetables, fruits, beans, eggs, meat and so on.

5. Be wary of intercourse

For pregnant women with a history of spontaneous abortion, sexual intercourse should be avoided within three months of pregnancy.

6. Do prenatal inspections regularly

Regular prenatal checkups should be started early in pregnancy to help doctors detect and handle abnormal conditions in a timely manner and guide health care during pregnancy.

7. Patients who have had spontaneous abortion should seek medical treatment as soon as possible once they become pregnant again.

references:

1. Wang Yan, Chen Gui'an, etc. Correlative study on the expression of interleukin 2 and interleukin 4 at the maternal-fetal interface of recurrent abortion with unknown causes: Journal of Reproductive Medicine, 2005: 14 (4) 208-213.

2. Lin Qide. Basic and clinical research progress of recurrent abortion that should have been unknown: Chinese Journal of Obstetrics and Gynecology, 2003: 38 (8): 481-3.