Prediction of pregnancy complication occurrence using fetal cardiac output assessments made by ultrasonography at 20 to 24 weeks of gestation

OBJECTIVE To evaluate the importance of assessment of fetal cardiac output (CO) for the prediction of complications of pregnancy. METHODS We evaluated 65 fetuses and all of them had a fetal cardiac scan at 20 to 24 weeks of pregnancy. To measure CO, diameters (d) of the left right ventricle outflow tract were measured just above the valves. Each left CO (LCO) and right CO (RCO) was derived using the following equation: CO = velocity time integral × π × d2/4 × heart rate. Pregnancy complications included gestational hypertensive disorders, fetal growth restriction (FGR) and preterm birth (PTB) caused from preterm labor or preterm premature rupture of membrane (PPROM). RESULTS There were 23 cases with one more pregnancy complication (FGR, 9; gestational hypertensive disorders, 8; PTB caused from PTB or PPROM, 12). The LCO was lower in complication group than in normal group (88±53 vs. 117±48 mL/min, P=0.028). The RCO to the LCO ratio (RCO/LCO) was higher in complication group (2.43±1.69 vs. 1.48±0.81, P=0.001). Regression analysis demonstrated that RCO/LCO was a significant predictor of pregnancy complication; Odds ratio was 7.76 (95% CI, 1.15 to 52.21; P=0.029). The area under the receiver-operating characteristic curve for prediction of pregnancy complications from LCO was 0.71. The diagnostic cut-off value of LCO was 80 mL/min. The area under the receiver-operating characteristic curve from RCO/LCO was 0.68 and cut-off value was 1.41. CONCLUSION This study demonstrated that pregnancy complications can be suspected based on fetal CO assessments at a GA of 20 to 24 weeks.