Context: Results from chromosome testing after spontaneous abortion (SAB) or intrauterine fetal demise (IUFD) are useful in patient counseling; however, results can be inconclusive when cell cultures for chromosomes are unable to grow from products of conception. Chromosomal microarray analysis (CMA) can analyze DNA from nonviable fetal tissue.
Objective: To examine whether establishing a genetic testing protocol for karyotype and CMA on SAB and IUFD tissues increases diagnostic yield.
Design: A retrospective chart review was conducted in cases of SAB or IUFD when karyotyping and/or CMA was requested, comparing two periods: Preprotocol and postprotocol implementation.
Main outcome measures: Diagnostic yield was compared by using the number of determinate test results in the preprotocol and postprotocol study periods. A case was considered to have indeterminate results when the final genetic test results reported no fetal tissue or no cell culture growth.
Results: A total of 55 preprotocol and 52 postprotocol patients were analyzed. Diagnostic yield increased from 72.7% to 94.2% after implementation of the genetic testing protocol (p = 0.0004). Indeterminate results occurred more frequently before compared with after implementation of the protocol.
Conclusion: A protocol of reflexing to CMA or proceeding directly with CMA gives a higher diagnostic yield in the genetic evaluation of SAB or IUFD. Institutions should consider implementing a genetic testing protocol to improve diagnostic yield. Our study results emphasize the importance of proceeding directly to microarray analysis and give support for current clinical recommendations for genetic testing after fetal demise.