The prognosis for successful pregnancy depends both on the potential underlying cause of pregnancy loss and (epidemiologically) on the number of prior losses (Table 33.4). As previously discussed, epidemiologic surveys indicate that the chance of a viable birth even after four prior losses may be as high as 60%. Depending on the study, the prognosis for successful pregnancy in couples with a cytogenetic etiology for reproductive loss varies from 20% to 80% (453– 455). Women with corrected anatomical anomalies may expect a successful pregnancy in 60% to 90% of cases (74,453,456–459). A success rate higher than 90% has been reported for women with corrected endocrinologic abnormalities (454). Between 70% to 90% of pregnancies reported among women receiving therapy for antiphospholipid antibodies have been viable (460,461).
Many forms of pre-or postconceptional tests have been proposed to help predict pregnancy outcome (201,219,327,462,463); none have been fully substantiated in large, prospective trials. The documentation of fetal cardiac activity on ultrasound may offer prognostic value; however, it appears that its predictions may be greatly affected by any underlying diagnosis. In one study, the live birth rate following documentation of fetal cardiac activity between 5 to 6 weeks from the last menstrual period was approximately 77% in women with two or more unexplained spontaneous abortions (464). It may be important to note that the majority of the patients in this study had evidence of inappropriate antitrophoblast cellular immunity. Others have shown that 86% of patients with antiphospholipid antibodies and recurrent pregnancy loss had fetal cardiac activity detected prior to subsequent demise (465). A prospective, longitudinal, observational study of 325 patients with unexplained recurrent pregnancy losses demonstrated that only 3% of 55 miscarriages occurred following the detection of fetal cardiac activity using transvaginal ultrasonography (466).
Table 33.4 Prognosis for a Viable Birth
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