Background. Spontaneous miscarriage isn’t an unexpected complication either in early spontaneous or in ART pregnancy. Previous studies showed that incidence of SM was slightly increased in ART ...pregnancies in comparison with spontaneous ones after adjusting for maternal age and previous SM. Our objective was to examine the relationship between SM and embryo quality after transfer of one or two blastocysts. Materials and methods. The total of 1433 stimulated IVF and ICSI cycles achieved in our center in the period from 2001 to 2002 after SBT or DBT were retrospectively analyzed. Of these, in the final analysis we included only cases with positive βhCG for which complete data on pregnancy outcome were available – 418 cycles in total. Results. The mean age of patients was 32.2 ± 4.5 years. IVF was performed in 133 cases and ICSI was performed in 285 cases, SBT in 69 and DBT in 349. After SBT, SM rate was 11.6 % and after DBT it was 12.0 %. In SBT group we didn’t find significant relationship between embryo quality and SM (logistic regression: c2 = 0.88; p > 0.05). In this groups, using standard statistical tests, we also couldn’t find significant difference in SM rate between subgroups where optimal or suboptimal quality blastocyst was transferred (Yates corrected c2 test: p > 0.05, Student’s t-test: p > 0.05). In DBT group, we found a strong relationship between embryo quality and SM (logistic regression: c2 = 10.12; p < 0.01). After standard analysis, we confirmed significant difference between subgroups with different combinations of blastocyst quality: after transfer of both optimal blastocysts SM rate was 8.5 %, after transfer of optimal and suboptimal blastocyst SM rate was 10.1 % and after transfer of both suboptimal blastocyst SM rate was 25.4 % (Kruskal-Wallis test: p < 0.001; one-way ANOVA: p < 0.001). We confirmed strong relationship between age of the patients and SM (logistic regression: c2 = 14.57; p < 0.0001). Conclusions. In our study SM rate was 11.9 % which was lower than in previous reports; it was even at the lower limit of expected SM rate in general population. This discrepancy was probably the consequence of longer selection period of blastocysts in in vitro conditions. We didn’t find a significant relationship between SM and blastocyst quality after SBT, which was probably due to the small sample size. A strong relationship between SM and blastocyst quality after DBT was proved. We also confirmed a strong relationship between age of the patients and SM.
