Is the absence of a yolk sac associated with chromosomal abnormality in early pregnancy loss?

Objective: To compare the abnormal karyotype rate between missed miscarriages with and without yolk sac (YS) and among groups with different YS intervals. Materials and Methods: Data of 214 patients who underwent dilation and curettage (D&C) for singleton pregnancy loss prior to 12th week of gestation were retrospectively analyzed. According to presence or absence of a YS on ultrasound, EPLs were divided into two groups. Ultrasound findings were correlated with karyotype analysis, which was performed by comparative genomic hybridization (CGH) plus fluorescence in situ hybridization (FISH) technology. Results: The chromosomal abnormality rate was significantly higher in EPLs with YS than without, either in all cases (50.0% vs. 28.0%, p <= 0.001) or in only male cases (57.4% vs. 31.8%, p <= 0.001). The yolk sac diameter (YSD) of EPLs with abnormal karyotypes was significantly larger compared to EPLs with normal karyotypes (4.7 +/- 2.2 vs. 4.1 +/- 2.3 mm, p <= 0.001). When classified into different intervals according to the YSD, there were statistical differences in abnormal karyotype rate among different intervals (p = 0.034). The abnormality rate increased with the YSD. When the YSD was 9.1-12 mm, the EPLs had the highest risk of chromosomal abnormality (75.0%); when the YSD was 0-3 mm, the risk was the lowest (41.9%). When compared to group A, the abnormality rates were significantly higher in B (p = 0.023), C (p = 0.033), and D (p = 0.048) groups. Conclusion: EPLs with YS had a higher risk of chromosomal abnormalities than without and the abnormality rate increased with the YSD.