Objectives: To establish the reference range for the parameters of uterine artery Doppler in the first trimester and investigate the usefulness of serum biomarkers and uterine artery Doppler findings in predicting small for gestational age (SGA) and pre-eclampsia (PE).Methods: In this retrospective study, we first presented the reference range of parameters of uterine artery Doppler in the first trimester and then grouped the 628 pregnant women according to the presence of SGA or PE and investigated the association of uterine artery Doppler findings and serum markers in the first trimester with the occurrence of SGA or PE.Results: The uterine artery PI, RI and the proportion of uterine artery notch decreased progressively in the first trimester.None of the Doppler parameters in the first trimester predicted SGA, while a low level of β-hCG significantly predicted SGA (OR = 0.55, 90% CI 0.33 -0.94).On the contrary, uterine artery notch, either on one side or both sides, significant predicted PE (notch at least on one side: OR = 8.62, 90% CI 1.09 -68.14 and notch on both sides: OR = 9.10, 90% CI 1.11 -74.54), while other parameters were not predictive of PE.Of the 268 subjects without a uterine artery notch in the first trimester, there was only one subject with a notch in the second trimester, who had neither SGA nor PE.Regardless of whether a notch was present in the second trimester or not, a uterine notch in the first trimester was associated with an excellent negative predictive value (99.6%) for PE.Conclusions: Although there were some variations in serum and Doppler biomarkers in the first trimester, a lower serum β-hCG level and the presence of the uterine artery notch in the first trimester significantly predicted SGA and PE, respectively.Moreover, the absence of a uterine artery notch in the first trimester was associated with a high-negative predictive value, which may be useful for preventing excessive examination and for prescribing medication for PE prevention in clinical settings.