What causes miscarriage?

Due to the accelerated pace of modern life and the pollution of the living environment, miscarriage often occurs after a woman becomes pregnant. Therefore, when a couple plans to have a baby, they must be fully prepared, have a healthy lifestyle, and pay attention to food hygiene. So, what are the causes of miscarriage?

1. Genetic defects In early spontaneous abortion, 50%-60% of embryos have chromosomal abnormalities, mostly due to abnormal chromosome numbers, followed by abnormal chromosome structures. Numerical abnormalities include trisomy, triploidy, and X-monomerism; structural abnormalities include chromosome breakage, inversion, deletion, and translocation. Most embryos with chromosomal abnormalities end in abortion, and a very small number may continue to develop into a fetus, but some functional abnormalities or combined deformities may occur after birth. If abortion has occurred, the product of pregnancy is sometimes only an empty gestational sac or a degenerated embryo.

2. Environmental factors There are many adverse external factors that affect reproductive function, which can directly or indirectly cause damage to the embryo or fetus. Excessive exposure to certain harmful chemicals (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 illness during pregnancy and high fever can cause uterine contractions and lead to 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, severe anemia or heart failure in pregnant women can cause fetal hypoxia and may also cause miscarriage. Chronic nephritis or hypertension in pregnant women may cause placental infarction and lead to miscarriage. (2) Reproductive organ diseases: Uterine malformations (such as double uterus, septate uterus and uterine hypoplasia) and pelvic tumors (such as uterine fibroids) in pregnant women can affect the growth and development of the fetus and lead to miscarriage. Relaxation of the internal cervix or severe cervical lacerations can easily lead to late miscarriage due to premature rupture of membranes. (3) Endocrine disorders: Hypothyroidism, uncontrolled severe diabetes, and luteal insufficiency can all lead to miscarriage. (4) Trauma: Abdominal surgery during pregnancy, especially in the early stages of pregnancy, or trauma in mid-pregnancy can cause uterine contractions and lead to miscarriage.

4. Insufficient placental endocrine function In early pregnancy, the corpus luteum of the ovary secretes progesterone, and the placental trophoblast cells also gradually produce progesterone. After 8 weeks of pregnancy, the placenta gradually becomes the main place for the production of progesterone. In addition to progesterone, the placenta also synthesizes other hormones such as β-chorionic gonadotropin, placental lactogen and estrogen. In early pregnancy, the above hormone values ​​decrease, and it is difficult to continue the pregnancy, resulting in miscarriage.

5. Immune factors Pregnancy is like allogeneic transplantation. There is a complex and special immunological relationship between the embryo and the mother, which prevents the embryo from being rejected. If the mother and the child are not immune compatible, it may cause the mother to reject the embryo and cause miscarriage. The relevant immune factors mainly include paternal tissue compatibility antigens, fetal specific antigens, blood type antigens, maternal cellular immune regulation disorders, insufficient maternal blocking antibodies during pregnancy, and insufficient maternal cytotoxic antibodies against paternal lymphocytes.

The above is an introduction to the causes of miscarriage. I hope it will be helpful to you. Everyone should take precautions in life.