Microbiology relevant to recurrent miscarriage.

The best evidence suggests that infection is an occasional cause of sporadic spontaneous abortion, and, consistent with statistical probability, recurrent miscarriage due to infection occurs with a frequency that is much lower. In the medical literature, the limited evidence linking infection and recurrent pregnancy loss in humans remains largely anecdotal and generally cannot be reproduced in prospective studies. This observation reflects the low frequency with which the necessary microbial and maternal factors combine to cause recurrent miscarriage. The patient's susceptibility to chronic infection must play a determining role in some of the reported cases. Susceptibility factors that allow severe chronic infection, such as immunocompromise, are rare in the general infertility population and may remain unrecognized in broad cumulative studies. Probable factors that play a role in the risk of abortion due to infection are the following: 1. Primary exposure during early gestation 2. The capability of the organism to cause placental infection 3. The development of an infectious carrier state 4. Immunocompromise caused by immunosuppressants, chemotherapy, corticosteroids, or acquired immune deficiency syndrome. Exposure to a microbe that can establish chronic infection that can spread to the placenta in an immunocompromised patient is probably the most obvious risk situation for habitual abortion. In routine medical practice, it is not necessary or efficient to screen universally for the unexpected, but it is necessary to be aware of the rare possibilities. Most patients with a history of recurrent miscarriage will not benefit from an extensive infection workup. All patients should first be categorized according to their own personal risk infection, as outlined in Table 2.(ABSTRACT TRUNCATED AT 250 WORDS)