Habitual miscarriage refers to pregnancy loss in 3 months. There are two types:
- Primary: without any prior successful pregnancy
- Secondary: repetitive losses follow a live birth
Repetitive miscarriage Reasons
- Genetic causes
- Immunologic causes
- Anatomic causes
- Infectious causes
- Environmental causes
- Endocrine causes
- Hematologic causes
The antiphospholipid syndrome is an autoimmune disease that is a common cause of recurrent pregnancy loss. Around 15% of the women who have recurrent miscarriages have high levels of antiphospholipid antibodies. Women who have had more than one miscarriage in the first trimester, or a miscarriage in the second trimester, may have their blood tested for antibodies, to determine if they have antiphospholipid syndrome.
Although the presence of antithyroid antibodies may represent a generalized autoimmune abnormality, which could be a contributing factor in miscarriages, screening for thyroid disease is not useful unless the patient is symptomatic.
Endocrine causes like thyroid, prolactin and insulin may be investigated with blood tests. Women with hypothyroidism are at increased risk for pregnancy losses. Unrecognized or poorly treated diabetes mellitus leads to increased miscarriages. Women with polycystic ovary syndrome also have higher loss rates possibly related to hyperinsulinemia or excess androgens. Inadequate production of progesterone in the luteal phase may set the stage for RPL.
If the likely cause of recurrent pregnancy loss can be determined treatment is to be directed accordingly. In patients with unexplained recurrent pregnancy loss chances are about 60-70% that the next pregnancy is successful without treatment. In certain chromosomal situations, while treatment may not be available, in vitro fertilization with preimplantation genetic diagnosis may be able to identify embryos with a reduced risk of another pregnancy loss which then would be transferred. Close surveillance during pregnancy is generally recommended for pregnant patients with a history of recurrent pregnancy loss. Even with appropriate and correct treatment another pregnancy loss may occur as each pregnancy develops its own risks and problems.