Issues in the etiology of recurrent spontaneous abortion.

Recurrent spontaneous abortion is seen often. Although many causes of this condition have been identified, there is still a large proportion in which no cause can be found. This review highlights some of the newly described proposed causes. Several reports have linked reproductive inefficiency to hypersecretion of luteinizing hormone (LH) in the follicular phase. It is apparent that the presence of inappropriate elevation of LH, and not the ultrasonographic appearance of polycystic ovaries, is the critical factor in determining the risk of abortion. Consequently, by lowering the LH levels one can expect a better reproductive outcome. This hypothesis awaits testing through clinical trials. The role of ultrasonography in evaluating the luteal phase, by assessing the image of the endometrium, has been studied by many investigators. This non-invasive technique is not yet able to replace the endometrial biopsy. The association between antisperm antibodies in the female serum and recurrent spontaneous abortion requires re-evaluation in light of more recent evidence; however, the role of semen abnormalities, especially severe oligospermia in this disorder, points towards a factor in the male partner that should be identified. Oligomenorrhea has been identified by mathematical modeling as a potential risk factor for recurrent abortion, although the mechanism has not been clearly elucidated. Chromosome heteromorphisms, particularly inv (9)(p11 q12), appear to be associated, more frequently, with recurrent abortion. Similarly, associations were observed with factor-XII deficiency and high titers of immunoglobulin G (IgG) antibody to Chlamydia trachomatis.(ABSTRACT TRUNCATED AT 250 WORDS)