Chapter 160 Abortion: Recurrent
INTRODUCTION
Description: When a woman has had two consecutive or three total first-trimester spontaneous pregnancy losses it is considered recurrent abortion.
ETIOLOGY AND PATHOGENESIS
Causes: Chromosomal abnormalities. When the losses occur early in gestation, there is a greater likelihood that a chromosomal abnormality is the cause, whereas for later abortions a maternal cause such as a uterine anomaly is more likely. Although most chromosomal abnormalities result from disorders of meiosis in gamete formation or in mitosis after fertilization, 5% of couples who experience recurrent abortion have a detectable parental chromosomal abnormality, surgically correctable uterine abnormalities, an incompetent cervix, or intrauterine synechiae. Uterine anomalies are found in 15% to 25% of women with recurrent abortion. The possibility of immunologic factors as a cause of recurrent losses should also be evaluated (e.g., lupus anticoagulant). Two thirds of recurrent abortions occur after 12 weeks of gestation, suggesting that maternal or environmental factors play a large role in this process.
