Current concepts in the pathogenesis of recurrent miscarriage

Abstract

Between 10 and 15% of clinically-recognized pregnancies abort spontaneously, usually during the first trimester. Thus, miscarriage is the most common complication of pregnancy. Recurrent spontaneous abortion (RSA), defined as the loss of three or more consecutive pregnancies, affects approximately 2% of women of childbearing age. In most cases, RSA is associated with random occurrence of chromosomally abnormal conceptions. Parental structural chromosomal rearrangements, congenital and acquired anatomic faults, endocrine disorders and silent infection of the genital tract each make a contribution to the etiology of RSA. In approximately one-half of the patients a putative cause can be identified, but whether it really is a cause of RSA often remains elusive. Although little is known about the exact mechanisms involved in the maternal-fetal immunological interaction, recent evidence indicates that in the pathogenesis of RSA, decidual natural killer cells play a vital role. One of the most promising areas for future research is, therefore, to elucidate the complex immunological mechanisms underlying pregnancy failure.