Value of Embryonic Heart Rates and Yolk Sac Size for Early Pregnancy Outcome

Objective: The aim of this study is to evaluate the prognostic value of embryonic heart rate and yolk sac size for the first trimester pregnancy outcome.Materials and Methods: This prospective observational study comprised of 195 pregnant women during their first trimester. Measurement of embryonic/fetal heart rate (EHR and FHR) is done using endovaginal ultrasound (M mode). Yolk sac measurement was performed from inner margins for the largest diameter obtained.Results: A significant linear correlation was detected, with Pearson correlation (r=0.516, p 0.001), when yolk sac diameter was evaluated in relation to increasing gestational age. The yolk sac diameter (mean ±SD) of cases in groups I, II, III, IV were 4.92 (1.74) mm, 3.86 (1.96) mm, 4.76 (2.68) mm and 2.13 (1.56) mm, respectively. The yolk sac diameter of groups I and III were significantly higher than that of group IV (p 0.001). ROC curve analysis demonstrated that cut- off point 0.914 for the Z value gives sensitivity and specificity values of 0.712 and 0.912, respectively. A significant correlation (r=0.701) was found between increasing fetal heart rate levels and advancing gestational age in cases with continued pregnancies beyond 12 weeks. ROC curve showed a prognostic value of combination of gestational age and fetal heart rate for pregnancy failure (area under the curve: 0.925).Conclusion: Pregnant women with embryonic heart rate and yolk sac size outside the range for viable pregnancy at corresponding gestational age may be at risk for eventually pregnancy loss.