The predictive value of the uterine artery pulsatility index during the early third trimester for the occurrence of adverse pregnancy outcomes depending on the maternal obesity.

PURPOSE: To identify the correlation between the pre-gravid maternal obesity and the uterine artery pulsatility index (UtA-PI) at 28-34 weeks' gestation, and to evaluate the predictive value of the UtA-PI for the occurrence of adverse outcomes depending on the maternal obesity.

METHODS

Between January 2010 and December 2011, 229 pregnant women were prospectively observed and analyzed. The UtA-PI during 28-34 weeks' gestation was estimated, with abnormal UtA-PI defined if the value was above the 95th centile for gestational age. The patients were classified, using a cut-off value for body mass index (BMI) of 25kg/m(2), into obese (pre-gravid BMI≥25kg/m(2)) and non-obese (pre-gravid BMI<25kg/m(2)) groups. We analyzed the association between the pre-gravid BMI and occurrence of abnormal UtA-PI and estimated their contributions to adverse outcomes using regression analyses.

RESULTS

The occurrence of abnormal UtA-PI in the women with pre-gravid BMI over 25kg/m(2) was significantly higher than those with normal pre-gravid BMI (OR: 2.49; 95% CI: 1.22-5.12). In multivariate analyses, the combination with abnormal UtA-PI and pre-gravid BMI over 25kg/m(2) contributed to the occurrence of preterm delivery (OR: 33.5; 95% CI: 7.63-147.21), gestational diabetes (OR: 3.98; 95% CI: 1.17-13.56) and pregnancy induced hypertension (OR: 12.71; 95% CI: 3.45-46.87), compared to the control group with pre-gravid BMI of 25kg/m(2) and less, and normal UtA-PI.

CONCLUSION

Women with pre-gravid BMI over 25kg/m(2) show increased tendency of abnormal uterine artery pulsatility index during 28-34 weeks, which increases the risk of adverse pregnancy outcomes.