The common causes of repeated miscarriages
Among the common causes of repeated miscarriages:
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Anatomical
An abnormal structure of the uterine cavity can damage implantation of the embryo and lead to miscarriage. These are mainly structural defects in the uterus that could be congenital or acquired.
A birth defect could be an abnormal uterine cavity due to abnormal development of the woman’s reproductive system.
Acquired defects could be intrauterine infections after undergoing a D&C or surgery to remove a fibroid, a number of fibroids, and/or polyps from the uterus.
Most miscarriages due to these defects occur in the second trimester. In cases of a uterine septum, which could be congenital or acquired, implantation of the embryo would be insufficient and often ends in a natural miscarriage in the first or second trimester.
In such a situation, miscarriage of genetically normal embryos could occur because the problem lies with the mother. Diagnostic hysteroscopy should be performed to diagnose defects in the uterus. This is a simple procedure in which an optical fiber is inserted into the uterus to photograph the uterine cavity.
Uterine defects are usually treated by surgical procedures.


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The immune system and autoimmune diseases
A group of diseases in which the immune system identifies healthy tissue as a foreign object without an actual foreign object, such as a bacterium or a virus, being present. As a result, antibodies are formed in the mother’s blood to attack the body’s own components. In other words, the mother’s antibodies attack herself and this could lead to the formation of blood clots in the blood vessels of the placenta that could hinder the blood supply to the embryo.
This usually causes miscarriage in early pregnancy. Patients who are diagnosed with immune system resistance and experience miscarriage of normal embryos are vaccinated by administering a drug called “immunoglobulin” that contains a concentration of the antibodies needed by the patient.
The APLA syndrome, also called the antiphospholipid antibody syndrome, is a syndrome that mainly manifests as hypercoagulability, thrombosis, and repeated miscarriages. This syndrome sometimes occurs in conjunction with an autoimmune disease called systemic lupus erythematosus.
In case of repeated miscarriages, anticoagulants, such as heparin or calcaneus, should be administered in the next pregnancy.
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Hypercoagulability
Repeated miscarriages in women can also be caused by hypercoagulability, which can result in miscarriage in relatively late stages of pregnancy.
Hypercoagulability of the blood is a condition of damage to the blood clotting mechanism: the blood clots too easily or too excessively.
For many years, it has been known that there are abnormal antibodies (antiphospholipids) that are able to attack the placenta and cause blood to clot in the blood vessels that supply blood, oxygen, and nourishment to the embryo. In such a case, the embryo will not get the amount of blood it needs and as a result, will not develop properly or will die. Recently, it has even been discovered that there are also genetic conditions of hypercoagulability, in which the blood clots without the antibodies causing it.
Hypercoagulability of the blood can be diagnosed and treated effectively. Anticoagulants can be used to prevent the blood from clotting and thus ensure the continuous supply of blood to the embryo.


Hormonal
- A low level of secretion of progesterone that is necessary to support the first weeks of development of the pregnancy until the placenta starts to produce it.
- Hypersecretion of the milk hormone (prolactin) – The main function of this hormone is to stimulate the production of milk in the mother’s breast after giving birth. The hormone also has an effect on the normal secretion of the hormones responsible for ovulation in the ovary. Hypersecretion of the milk hormone often causes infertility and hinders ovulation.
- Hyperthyroidism or hypothyroidism
- Women suffering from diabetes, especially those in whom the disease is not well balanced.
Women can be treated with medication to lower prolactin levels, to balance diabetes, or to increase the level of progesterone. Hypercoagulability is also treated with medication, using anticoagulants.


Cervical insufficiency
These are women who suffer from repeated miscarriages at a later stage (in the second trimester of pregnancy) and also women who give birth prematurely.
Most often, cervical insufficiency is the result of cervical dilation (dilatation) that assists the birth or from a D&C. During the D&C process, it’s necessary to widen the cervix in order to empty out the uterus. Sometimes, also trauma, damage, or other surgical procedures done on the cervix can cause cervical insufficiency to develop during the pregnancy.
Women who are diagnosed with cervical insufficiency can try to prevent a repeated miscarriage by undergoing cervical stitching (cerclage) in the 13-15th week of their pregnancy.
Other causes of repeated miscarriages
The following are also important causes: the woman’s age, the woman’s background of diseases, infections, the number of previous miscarriages, obesity and insulin resistance, vitamin D deficiency, smoking, excessive alcohol consumption, drugs, excessive caffeine consumption, as well as depression and anxiety.