To investigate the changes of uterine-placental hemodynamics and fetal growth and development indexes in the second trimester in women with overweight or obesity before pregnancy.

One hundred and twenty-seven pregnant women who underwent prenatal examination and fetal echocardiography at Tangdu Hospital from June 2019 to September 2020 were included. According to the pre-pregnancy body mass index, the pregnant women were divided into normal (n=55), overweight (n=45), and obese pregnant women (n=27). The general data of the three groups of pregnant women, uterine-placental blood flow, fetal biological measurement indicators, and middle cerebral artery and umbilical artery blood flow were compared.

Compared with pregnant women in the normal group, the uterine artery peak blood flow velocity (Vs), end-diastolic blood flow velocity (Vd), and pulsatility index (PI) of the pregnant women in the overweight and obese groups significantly increased (P＜0.05), and PI of bilateral uterine arteries of pregnant women in the obesity group were higher than those of the overweight group (P＜0.05). Compared with the normal group, the blood flow velocity of the free segment of the umbilical artery in the obesity and overweight groups was reduced to varying degrees, and the difference among the three groups was statistically significant (Vs: F=4.41, P=0.01; Vd: F=4.03, P=0.02); further pairwise comparisons showed that the Vd differed significantly between the overweight group and the normal group (P＜0.05), and Vs differed significantly between the obese group and normal group (P＜0.05).

There have been significant differences in uterine-placental circulation hemodynamics between pre-pregnancy overweight and obese pregnant women in the second trimester compared with the normal group. Timely monitoring of the changes in these indicators has potential value in guiding the clinical reasonable control of pregnant women's weight and reducing possible complications in later period.