Role of first-trimester umbilical vein flow in predicting fetal macrosomia: a matched case-control study.
To describe umbilical vein (UV) hemodynamic in macrosomic fetuses at 11+0 13+6 weeks of gestation and to build a multiparametric prediction model including pregnancy and ultrasound characteristics able to detect fetal macrosomia in the first trimester. Matched case-control study including pregnancies who underwent ultrasound examination at 11+0 to 13+6 weeks for aneuploidy screening at a single centre over a four years period. Cases were women who gave birth a newborn with a BW >90th centile for gestational age and sex according to local birthweight standards, while controls those who delivered newborns with a BW ranging between the 10th and 90th centiles matched by a ratio of 1:3 for maternal age and gestational age. Each included case underwent Doppler assessment of uterine arteries and UV haemodynamic, including its diameter, time-averaged maximum velocity (TAMXV) and blood flow (UVBF. Fisher's and Mann-Whitney U-test test were used to compute differences in maternal biochemical and ultrasound characteristics between pregnancies complicated and those not complicated by fetal macrosomia, while logistic regression and receiver operating characteristics curve (ROC) analyses were carried out to look for independent predictors and to build a multiparametric prediction model for fetal macrosomia integrating different maternal, pregnancy and ultrasound characteristics. . A sub-group analysis was also computed considering women delivering newborns with a BW >4000g. Nine hundred and sixty-four pregnancies (241 complicated and 723 not complicated by fetal macrosomia) were included in the study. UV TAMXV (z-score=0.8, IQR 0.4-1.5, vs. 0.0, IQR -0.3-0.5; p≤ 0.001) and UVBF (z-score=1.3, IQR 0.8-1.9 vs. 0.1, IQR -0.4-0.4; p≤ 0.001) were higher in macrosomic fetuses compared to controls, while there was no difference in the median umbilical vein diameter between fetuses with and those without macrosomia (p= 0.56). Likewise, median uterine PI MoM (0.94, IQR 0.78-1.12, vs. 1.02, IQR 0.84-1.19; p= 0.04) was significantly lower in macrosomic fetuses. On multivariate logistic regression analysis, maternal BMI (aOR: 1.2, 95% CI 1.2-1.7; p<0.001), parity (aOR: 1.4, 95% CI 1.2-1.6; p<0.001), PAAP-A MoM (aOR: 1.1, 95% CI 1.0-1.6; p= 0.004) and UVBF (aOR: 1.6, 95% CI 1.1-1.9; p<0.001) were independently associated with macrosomia. A multiparametric model integrating parity, BMI and PAPP-A provided an AUC of 0.72 (95% CI 0.67-0.76) for the prediction of macrosomia. The addition of UVBF to this model significantly improved the prediction of fetal macrosomia provided by maternal and biochemical factors, with an AUC of 0.79 (95% CI 0.75-0.83; p=0.03). Likewise, the same model incorporating UVBF predicted a BW >4000 g with an AUC of 0.83 (95% CI 0.75-0.83) CONCLUSIONS: UVBF measured at the time of 11-14 weeks scan is independently associated and predictive of fetal macrosomia and BW >4000g. Adding measurement of UVBF to a multiparametric model that included maternal (parity, BMI) and biochemical (PAPP-A) parameters improves the diagnostic accuracy of a prenatal screening for fetal macrosomia. This article is protected by copyright. All rights reserved.