Current concepts and new trends in the diagnosis and management of recurrent miscarriage.

Pregnancy is a proinflammatory and hypercoagulable state. Miscarriage concerns approximately 15% of pregnancies. Recurrent miscarriage is a rather rare condition with an estimated incidence of 1% to 3%. However, despite years of investigation, the etiology is not established in up to 50% of cases. A multidisciplinary approach in the evaluation of miscarriage is essential to understand the cause and risk of recurrence. Although genetic factors are the major cause of spontaneous miscarriages, their relationship with recurrent miscarriage is less frequent. Recently, many kinds of genetic polymorphisms have also been found to be associated. Endocrine disorders such as poorly controlled diabetes, polycystic ovary syndrome, and hypothyroidism are linked with recurrent miscarriage. The relationship between recurrent miscarriage and subclinical thyroid disorders and thyroid autoimmunity is disputed, especially in early miscarriages. Uterine malformations should be considered as a cause of recurrent miscarriage. Although autoimmune-based recurrent miscarriage has been described, mainly antiphospholipid antibodies, the role of alloimmune mechanisms remains poorly understood. The influence of congenital thrombophilia is controversial. Antiphospholipid syndrome or antiphospholipid antibody-related recurrent miscarriage, and some endocrinologic disorders, have a specific and effective treatment. Still, the effectiveness of some common treatments needs to be demonstrated.