HIGH FAILURE RATE OF POSTMORTEM KARYOTYPING AFTER TERMINATION FOR FETAL-ABNORMALITY

Objective: To determine the failure rate of karyotyping from samples t aken after termination of pregnancy for fetal abnormality. Methods: Pe rinatal autopsy reports over a 12-month period were reviewed to identi fy those with cytogenetic studies performed after termination of pregn ancy for fetal abnormality. Results: During the audit period, there we re 104 terminations for fetal abnormality. In 89 fetuses, fetal skin ( n = 85), placenta (n = 62), or other samples (n = 8) were obtained for postmortem cytogenetic analysis. In 24 (27%) fetuses, postmortem tiss ues did not yield a karyotype result. The failure rate of post-termina tion karyotyping was significantly influenced by delivery-sampling int erval, but not by gestational age, type of tissue sampled, use of pota ssium chloride, or aneuploidy. Of the 24 cases for which no post-termi nation karyotype was obtained, 16 had had successful pre-termination k aryotyping, resulting in only eight of 89 (9%) cases in the overall se ries not having a final karyotype. Conclusion: The high failure rate f or post-termination karyotyping suggests that a pre-termination proced ure is necessary if parents wish to have almost 100% certainty that cy togenetic information will be available for later genetic counseling.