Selective karyotyping in recurrent miscarriage: are recommended guidelines adopted in daily clinical practice?

BACKGROUND Couples with recurrent miscarriage (RM) have an increased risk of one of the partners carrying a structural chromosome abnormality. On the basis of four independent risk factors, an evidence-based model was developed, which allows limiting karyotyping to high-risk couples. The aim of this study was to assess the level of adoption of selective karyotyping, its clinical consequences and the factors at the patient and hospital level that determine adoption. METHODS A retrospective cohort study was performed in nine Departments of Obstetrics and Gynaecology, the Netherlands, in 2006. Selective karyotyping was defined as offering karyotyping to high-risk couples and refraining from karyotyping in low-risk couples. Data were collected for risk factors as described in the model for selective karyotyping, cytogenetic results as a measure for clinical consequences, and information about determinants and costs. RESULTS A total of 530 couples were included; 252 (48%) high-risk couples and 278 (52%) low-risk couples. Among the high-risk couples, 186 (74%) were offered karyotyping. Although not advised, karyotyping was still performed in 198 (71%) low-risk couples. Overall, selective karyotyping was offered to 50% of the couples. The main determinants for adoption of the model were maternal age, obstetric history, treatment by specialists in RM and the number of patients per centre. If selective karyotyping was adopted adequately, a potential reduction of 34% of all karyotyping tests performed is possible. CONCLUSION Selective karyotyping is applied in only half of the couples with RM in daily practice. Implementation of selective karyotyping should be a topic of future research.