What are the factors that cause women to suffer from habitual abortion?

Patient's question:

Will it cause women to suffer from habitual abortion? Took three years to have a child, lost four, still want to, must get pregnant

Doctor's answer:

First, low immune system function. Low immune system function is the second cause of habitual abortion in women. The embryo is also a foreign body to the mother, so it is inevitably rejected by the mother's immune system. With a low immune system function in women, the embryo will be expelled as a foreign body.
Second, luteal phase defect. Habitual abortion is only a symptom, and behind this symptom lies the root cause of the disease. Luteal phase defect is one of the main causes of habitual abortion in women. 40% of women with habitual abortion are caused by luteal phase defect. This is one of the reasons for habitual abortion. After ovulation, the corpus luteum forms, secreting progesterone and estrogen. After conception, the corpus luteum continues to maintain pregnancy for 4–6 months before it begins to degenerate. After the zygote implants in the uterus, the syncytiotrophoblast differentiates from the oocyte cells, and its secretions enter the mother's body, prolonging the lifespan of the corpus luteum and stimulating its synthesis of progesterone to maintain pregnancy.
Third, genetic factors. Genetic genes are the third cause of habitual abortion, including: consanguineous marriage. The closer the blood relationship between husband and wife, the easier it is for the next generation to have chromosomal abnormalities. Most embryos with chromosomal abnormalities cannot survive and result in abortion. Some may also develop into malformed fetuses, delayed fetal development, or even survive but exhibit dominant genetic chromosomal abnormalities. Therefore, the state prohibits consanguineous marriage.