Results
A total of 6, 233 women were recruited in this study. The overall rate of underweight, normal-weight and overweight/obese women was 19.2% (1, 203/6, 233), 61.3% (3,821/6,233) and 19.4% (1,209/6,233), respectively. Among the overweight/obese women, pre-BMI range of 23 to 25 kg/m2 was 10.6% (661/6, 233), pre-BMI range of 25 to 30 kg/m2 was 7.3% (455/6, 233), and pre-BMI range ≥ 30 kg/m2 was 1.5% (93/6, 233). As presented in Table 1, mean age of the women grouped by the pre-BMI were 29.5±3.94 years, 31.4±4.3 years, and 32.6±4.17 years, respectively (p < 0.001). Table 1 showed maternal lipid profiles at GDM diagnosis stratified by pre-BMI. Serum TC level of underweight women was significantly higher than overweight/obese women (p < 0.001). The concentration of TG in underweight women was significantly lower than those in normal-weight women and overweight/obese women (p < 0.001), and the concentration of HDL-c was on the contrary (p < 0.001). In addition, TG/HDL-c ratio of underweight women was significantly lower than normal-weight and overweight/obese women (p < 0.001).
Among the 6, 233 women, 1, 363 (21.9%) cases were diagnosed with GDM, and 256 (4.1%) cases were diagnosed with GH/PE as shown in Table 2. In addition, there were 507 (8.1%) cases with PTB, 305 (5.0%) cases with LGA, 642 (10.3%) cases with SGA and 432 (6.9%) cases with PPH. The occurrences of GDM and GH/PE in overweight/obese women were significantly higher than those in underweight and normal-weight women (p < 0.001). The occurrence of LGA in underweight women was significantly lower than those in normal-weight women and overweight/obese women (p < 0.001), and the odds of SGA was on the contrary (p < 0.001). Besides, underweight women had lower risk of PPH, compared with normal-weight women and overweight/obese women. However, there was significant difference only between the underweight group and normal-weight group (p = 0.008).
Odd ratios between maternal lipid profiles at GDM diagnosis and adverse pregnancy outcomes in underweight women were displayed in Table 3. After adjusting for maternal age, underweight women with high TC level had significantly higher occurrence of LGA [OR=2.24, 95%CI (1.08, 4.63)], and lower occurrence of SGA [OR=0.71, 95%CI (0.59, 0.85)], while there were no significant associations between serum TC and LGA or SGA in normal-weight women and overweight/obese women (Table 3 or Table 4). Underweight women with high TG levels had significantly higher incidence of GDM [OR=1.21, 95%CI (1.01, 1.44)] and GH/PE [OR=1.73, 95%CI (1.10, 2.74)], which were similar in normal-weight women and overweight/obese women (Table 4), but a significantly lower incidence of SGA [OR=0.79, 95%CI (0.66, 0.94)]. In addition, the increase of LDL-c [OR=0.70, 95%CI (0.59, 0.84)] and TG/HDL-c ratio [OR=0.79, 95%CI (0.66, 0.94)] had a decreased risk for SGA in underweight women, but no significant relationship was found in overweight/obese women (Table 4).