Mid-trimester loss--appraisal of a screening protocol

The main causes for mid-trimester loss are known. There is likely to beoverlap with those of first trimester loss, but the proportions may bedifferent. We wished to perform an aetiological survey in a largepopulation of patients with a history of recurrent miscarriage, forpossible explanations for their second trimester miscarriages. Databaseanalysis of 636 patients attending a UK University Teaching Hospitaldedicated miscarriage clinic between 1991 and 1996 revealed a 25%prevalence (n = 158) for second trimester miscarriage. Results from aninvestigative screening protocol were positive in 50% of cases: 33% (n =52) tested positive for antiphospholipid syndrome (APS); 8% (n = 13)fulfilled strict criteria for cervical incompetence; there was a 4%prevalence of uterine anomaly; 3% for infection (n = 5) and 2% of patients(n = 3) proved to be hypothyroid. Importantly, dual pathology was found in5% of patients with a history of second trimester miscarriage. Asidiopathic mid-trimester loss is a diagnosis by exclusion, a high index ofsuspicion is required, as are modern diagnostic techniques.