According to the American Society of Reproductive Medicine, recurrent abortion is defined as the loss of two or more previable (less than 24 weeks’ gestation or 500 g) pregnancies in succession. Recurrent abortion affects about 1–5% of couples. Abnormalities related to recurrent abortion can be identified in approximately 50% of these couples. If a woman has lost three previous pregnancies without identifiable cause, she still has at least a 55% chance of carrying a fetus to viability.
Recurrent abortion is a clinical rather than pathologic diagnosis. The clinical findings are similar to those observed in other types of abortion. It is appropriate to begin a medical evaluation in a woman who has had two first-trimester losses.
Preconception therapy is aimed at detection of maternal or paternal defects that may contribute to abortion. A thorough history and examination is essential. A random blood glucose test and thyroid function studies (including thyroid antibodies) can be done if history indicates a possible predisposition to diabetes mellitus or thyroid disease. Detection of lupus anticoagulant and other hemostatic abnormalities (proteins S and C and antithrombin deficiency, hyperhomocysteinemia, anticardiolipin antibody, factor V Leiden mutations) and an antinuclear antibody test may be indicated. Hysteroscopy, saline infusion sonogram, or hysterography can be used to exclude submucosal myomas and congenital anomalies of the uterus. In women with recurrent losses, resection of a uterine septum, if present, has been recommended. Chromosomal (karyotype) analysis of both partners can be done to rule out balanced translocations (found in 3–4% of infertile couples), but karyotyping is expensive and may not be helpful.
Many therapies have been tried to prevent recurrent abortion from immunologic causes. Low-molecular-weight heparin (LMWH), aspirin, intravenous immunoglobulin, and corticosteroids have all been used but the definitive treatment has not yet been determined (see Antiphospholipid Syndrome, below). Prophylactic low-dose heparin and low-dose aspirin have been recommended for women with antiphospholipid antibodies and recurrent pregnancy loss.
B. Postconception Therapy
The patient should be provided early prenatal care and scheduled frequent office visits. Empiric sex steroid hormone therapy is complicated and should be done by an expert if undertaken.
The prognosis is excellent if the cause of abortion can be corrected or treated.
HA. Modern management of recurrent miscarriage. Aust N Z J Obstet Gynaecol. 2019 Feb;59(1):36–44.