Strengths and limitations
This was a cross-sectional study that collected the clinical data of pregnant women who had given birth at our center. All singleton pregnancies were included during the period except those with fetal structural or chromosomal abnormalities or missing data. Compared to the other studies analyzed in the population high-risk for FGR, our data tended to summarize and analyze the data in a general population. It was because third-trimester growth ultrasound was part of routine prenatal care late pregnancy ultrasound in China. Besides, this study compared the three most common FGR definitions in one paper in order to make a more comprehensive and convictive conclusion, thereby providing evidenct on choosing the most suitable FGR definition for Chiense population.
However, this study has limitations. The primary and secondary outcomes of this study only focused on the neonatal period, but not the long-term complications. Therefore, we should continue to follow up on long-term neurological development disorders and the incidence of cardiovascular and metabolic diseases in the children with suspected FGR. Because the number of early FGR cases in this study was relatively small, we did not distinguish early FGR and late FGR in this study. In the future, we hope to perform prospective studies and increase the sample size. Additionally, this study mainly used the last ultrasound biometrics as indexes to assess growth potential. However, obviously, according to the core meaning of FGR, it would make more sense if the fetal growth curve could be tracked during the whole pregnancy. Therefore, the next step was to improve the FGR detection rate by studying longitudinal changes in FGR.