Causes of recurrent spontaneous abortion

Recurrent miscarriage, also known as habitual miscarriage, is the most terrifying type of miscarriage, which brings both physical and mental trauma to women who want to have children. Recurrent miscarriage is relatively difficult to treat. So, what are the causes of recurrent miscarriage? Experts say that the main causes are reproductive factors and genetic immune factors. Let's take a look at the detailed introduction.

Reproductive anatomy

1. Uterine malformation: Uterine septate, unicornuate uterus, bicornuate uterus, saddle-shaped uterus and other malformations can lead to a decrease in the volume of the cervix, a decrease in the ability to adapt to expansion, or poor blood circulation, which may affect the implantation of the fertilized egg and the development of the embryo.

2. Cervical insufficiency: Uterine malformations are often accompanied by cervical insufficiency. In addition, trauma, surgery, early abortion, uterine curettage, and multiple spontaneous abortions can all lead to cervical insufficiency. The cervix cannot effectively withstand the increasing intracervical pressure and weight after pregnancy, causing the cervix to expand slowly, often leading to spontaneous abortion.

3. Cervical adhesion: Whether it is abortion curettage, curettage for retained placenta or fetal membranes, or other surgical operations, there is a possibility of causing cervical adhesion. Some adhesions can cause deformation of the uterine cavity or endometrial abnormalities, affecting placental formation and nutritional disorders, leading to miscarriage.

4. Uterine fibroids: According to the classification of uterine fibroids, submucosal fibroids have the highest chance of spontaneous abortion, while subserosal fibroids generally do not cause miscarriage. Whether miscarriage occurs is related to the location, size, and number of the fibroids. If the fibroids change the size of the uterine cavity or partially block the uterine cavity, the endometrial blood circulation will be impaired, interfering with the implantation of the fertilized egg, the formation of the placenta, and the development of the embryo, leading to miscarriage.

Genetic and immune factors:

1. HLA and spontaneous abortion: This is a type of antigen that exists on the cell surface and can cause a strong rejection response. For the mother, the embryo is a half-self and half-foreign immune transplant, so tissue HLA is of great significance in the immune response related to embryo survival. HLA can be divided into A, B, C, D and DR. When the mother's immune system rejects the fetus, it can lead to spontaneous abortion.

2. Blood type antigen system and spontaneous abortion: Among couples with ABO blood type incompatibility, about 1/5 suffer miscarriage. The mechanism is that there are cracks or certain defects in the placental barrier, which allow fetal red blood cells to have the opportunity to enter the mother through the placenta, sensitizing the mother to produce corresponding antibodies. The antibodies then cross the placenta and interfere with the fetal organ formation and embryonic development, leading to miscarriage. When the Rh blood types are different, if the husband is Rh+ and the wife is Rh-, the Rh+ fetal red blood cells can enter the mother through the placenta and produce antibodies. The antibodies enter the fetus and cause damage to the fetus, resulting in miscarriage.

The above is an introduction to the causes of recurrent spontaneous abortion. I hope it will be helpful to you.