Baseline characteristics
The mean age of all included subjects was 26.6±3.7 years. 223 (4.3%) were PTB; 126 (2.3%) gave birth to LBW infants; The incidence of SGA was 316 (5.8%). Women who delivered PTB infants or LBW infants had higher prevalence of HDP (P <0.05); Compared with full-term women, women who gave PTB have a lower proportion of rural residents (P <0.05); Mothers who gave birth to LBW babies had a higher proportion of non-births than mothers who gave birth to NBW babies (P <0.05); The proportion of mothers who delivered SGA, young in age, annual household income ≤49,999, pre-pregnancy weight, insufficient weight gain during pregnancy and non-birth was higher, and the incidence of gestational diabetes was lower (P <0.05), as detailed in Table 1.