To evaluate the right myocardial performance index(RMPI) of normal fetuses during the second and third trimesters of pregnancy by using an intelligent detection technology of myocardial performance index.

A total of 465 healthy pregnant women who underwent prenatal examination at the First Affiliated Hospital of Medical College of Shantou University from September 2019 to April 2020 were selected. According to the gestational age, the pregnant women included in the study were divided into three groups: 172 cases in the 21⁺⁰~27⁺⁶ week group, 169 in the 28⁺⁰~34⁺⁶ week group, and 124 in the 35⁺⁰~40⁺⁶ week group. The blood flow spectrum images of all fetal tricuspid valves and pulmonary valves were taken, and an intelligent detection system of myocardial performance index was used to measure the fetal isovolumetric contraction time(ICT), isovolumetric relaxation time(IRT), ejection time (ET), and RMPI. The differences of each parameter among the three groups with different gestational ages and the correlation between RMPI and gestational age were analyzed.

There were significant differences in RMPI and IRT among the three groups(F=26.433, 34.359,P＜0.05 for both), although no significant differences were observed in ICT and ET among the three groups (F=0.445, 0.743, P＞0.05 for both). Further pairwise comparison showed that there were significant differences in IRT and RMPI between the 21⁺⁰~27⁺⁶ week group and 28⁺⁰~34⁺⁶week group (P＜0.05 for both), in RMPI between the 28⁺⁰~34⁺⁶week group and 35⁺⁰~40⁺⁶ week group (P＜0.05), and in IRT and RMPI between the 21⁺⁰~27⁺⁶ week group and 35⁺⁰~40⁺⁶ week group (P＜0.05 for both).Pearson correlation analysis showed that there was a weak linear correlation between RMPI and gestational age (r=0.340, P＜0.05).

RMPI is affected by gestational age, and there is a weak linear correlation between them. The measurement of RMPI in normal fetuses in the second and third trimesters of pregnancy by ultrasonic intelligent detection technology provide abasis for clinical evaluation of fetal cardiac function.