What causes miscarriage?

After becoming pregnant, female friends need to go through a difficult gestation process before the baby finally comes to fruition. They also need to take good care of their daily life and diet to prevent miscarriage. Unfortunately, miscarriage brings a great blow to every family. So, what are the causes of miscarriage? Let's listen to the experts' introduction.

The main causes of miscarriage are:

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.

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. If pregnant women suffer from chronic nephritis or hypertension, the placenta may infarct and cause miscarriage.

(2) Reproductive organ diseases: Uterine malformations (such as double uterus, uterus septate and uterine hypoplasia) and pelvic tumors (such as uterine fibroids) 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: Insufficient luteal function often affects the decidua and placenta, leading to miscarriage. People with hypothyroidism may also suffer miscarriage due to poor embryo development.

(4) Trauma: Abdominal surgery during pregnancy, especially in the early stages of pregnancy, or trauma during mid-pregnancy can stimulate uterine contractions and cause miscarriage.

Placental endocrine insufficiency:

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 site 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 the pregnancy will be difficult to continue, resulting in miscarriage.

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.