SIGNIFICANCE OF YOLK-SAC MEASUREMENTS WITH VAGINAL SONOGRAPHY IN THE FIRST-TRIMESTER IN THE PREDICTION OF PREGNANCY OUTCOME

Background. The purpose of this prospective clinical study was to dete rmine and evaluate the prognostic value of secondary yolk sac diameter of the embryo on pregnancy outcome. Methods. One hundred and thirty p regnant women in the first trimester were included in the study. Crown -rump length (CRL) and yolk sac diameters were measured in every patie nt and the outcome of the pregnancies were compared with the measureme nts, Intact normal pregnancy (group A), threatened abortion (group B) and missed abortion (group C) were diagnosed in 67, 43 and 20 pregnanc ies, respectively. Results. We detected a significant linear correlati on between secondary yolk sac diameter and gestational age in group A (r = 0.5085; p < 0.0001) and a moderate correlation in group B (r = 0. 4048; p = 0.007) and C patients (r = 0.3478; p = 0.1333). When the gro ups were evaluated irrespective of gestational age, a significant diff erence in secondary yolk sac diameters among the groups was noted (p = 0.037). When confidence intervals for secondary yolk sac diameters of intact normal pregnancies (group A) were calculated by linear regress ion, two patients in group B were below the 5% confidence interval. Ho wever, in group C patients, the yolk sac diameter of six patients were detected below the 5% confidence interval, while two of the measureme nts were above 95% confidence interval. Therefore, eight measurements (40%) of group C patients were outside the 5-95% confidence interval. Conclusion. In the first trimester, when discrepancy is detected betwe en secondary yolk sac diameter and gestational age, additional sonogra phic investigation should be performed one or two weeks later, in orde r to estimate the pregnancy outcome.