The percentages differ by population and center carrying out the study; however, the relationship between spontaneous miscarriages and Endometriosis has been a matter of controversy for quite a while. Many investigators have shown that the rate of miscarriage is higher in patients with Endometriosis and shows a marked decline after effective treatment. It is believed that alterations in humoral and cell-mediated immunity and the biochemistry of the hormones in Endo patients can explain this; for example, decreased serum progesterone in some of the patients and an increased serum prolactin in others. Also, the basic autoimmune profile in Endo patients also attributes to it. The rate of miscarriage in the general population (those WITHOUT Endo) is reported as 15-20%, which means 15-20% of recognized pregnancies result in miscarriage. The frequency of spontaneous miscarriage increases further with maternal age. With the development of highly sensitive assays for hCG levels, pregnancies can be detected prior to the expected next period. When these highly sensitive hCG assays are used early, the magnitude of pregnancy loss significantly increases to about 60-70%. Late implantation by the conceptus beyond the usual 8-10 days after ovulation also has an increased risk of miscarriage. About 80% of miscarriages occur within the first trimester. The frequency of miscarriage decreases with an increasing gestational age. Recurrent miscarriage, defined as 2-3 pregnancy losses, affects about 1% of all couples. No significant difference exists between international rates and the rates in the United States. Hope that helps.
