Table 2. Comparison of pregnancy outcomes between pre-pregnancy underweight, normal weight, overweight and obese women.
| Underweight | Normal weight | Overweight | Obesity | p-value* | ||
|---|---|---|---|---|---|---|
| BMIa < 18.5kg/m2 | 18.5≦BMI < 25kg/m2 | 25≦BMI < 30kg/m2 | BMI≧30kg/m2 | |||
| n = 17724 | n = 69126 | n = 7502 | n = 2805 | |||
| PIHb | ||||||
| %(n) | 3.34%(n = 592) | 4.68%(n = 3237) | 10.08% (n = 756) | 14.65%(n = 411) | <0.001 | |
| OR(95%CI) | 0.724(0.657–0.798) | 1 | 2.373 (2.125–2.649) | 3.693 (3.170–4.302) | ||
| GDMc | ||||||
| %(n) | 2.66%(n = 472) | 3.86%(n = 2665) | 10.72% (n = 804) | 20.61%(n = 578) | <0.001 | |
| OR(95%CI) | 0.737(0.663–0.819) | 1 | 2.905 (2.645–3.189) | 6.582 (5.833–7.427) | ||
| SGAd | ||||||
| %(n) | 13.21%(n = 2341) | 8.67%(n = 5992) | 7.24% (n = 543) | 7.06% (n = 198) | <0.001 | |
| OR(95%CI) | 1.657 (1.557–1.764) | 1 | 0.807 (0.731–0.891) | 0.790(0.688–0.908) | ||
| LGAe | ||||||
| %(n) | 5.46%(n = 967) | 10.05%(n = 6944) | 17.36% (n = 1302) | 22.60% (n = 634) | <0.001 | |
| OR(95%CI) | 0.50 (0.466–0.536) | 1 | 1.96 (1.834–2.094) | 2.709 (2.457–2.988) | ||
| Preterm birth | ||||||
| %(n) | 12.2%(n = 2154) | 10.2%(n = 7063) | 11.6%(n = 873) | 12.1% (n = 338) | <0.001 | |
| OR(95%CI) | 1.236(1.164–1.313) | 1 | 1.133 (1.043–1.230) | 1.187 (1.044–1.350) | ||
| Spontaneous preterm birth | ||||||
| %(n) | 10.2%(n = 1810) | 8.3%(n = 5751) | 8.8%(n = 662) | 9.1% (n = 256) | <0.001 | |
| OR(95%CI) | 1.275(1.196–1.359) | 1 | 1.037 (0.937–1.134) | 1.085 (0.937–1.256) | ||
| PPROMf | ||||||
| %(n) | 3.78%(n = 670) | 3.01%(n = 2081) | 3.35%(n = 251) | 3.35% (n = 94) | <0.001 | |
| OR(95%CI) | 1.261(1.145–1.3890) | 1 | 1.114 (0.976-Ⅰ.273) | 1.115 (0.893–1.392) | ||
| Induce preterm birth | ||||||
| %(n) | 1.9%(n = 344) | 1.9%(n = 1317) | 2.8%(n = 211) | 2.9% (n = 82) | <0.001 | |
| OR(95%CI) | 1.034(0.922–1.160) | 1 | 1.509 (1.302–1.748) | 1.573 (1.232–2.010) | ||
| Total C/Sg | ||||||
| %(n) | 22.54%(n = 3995) | 26.95%(n = 18627) | 36.78%(n = 2759) | 42.96% (n = 1205) | <0.001 | |
| OR(95%CI) | 0.857 (0.818–0.897) | 1 | 1.506 (1.420–1.597) | 2.042 (1.855–2.248) | ||
| PPHh with VDi | ||||||
| %(n) | 19.57%(n = 3468) | 20.94% (n = 14476) | 21.22% (n = 1592) | 22.07% (n = 619) | <0.001 | |
| OR (95%CI) | 0.886 (0.842–0.932) | 1 | 1.070 (0.999–1.146) | 1.104 (0.995–1.226) | ||
| PPH with C/S | ||||||
| % (n) | 4.74% (n = 840) | 7.64% (n = 5281) | 11.37% (n = 853) | 13.80% (n = 387) | <0.001 | |
| OR (95%CI) | 0.659 (0.601–0.722) | 1 | 1.461 (1.338–1.595) | 1.91 (1.684–2.167) | ||
| macrosomia>4000g | ||||||
| % (n) | 0.27% (n = 47) | 0.69% (n = 474) | 1.76% (n = 132) | 3.07% (n = 86) | <0.001 | |
| OR (95%CI) | 0.375 (0.280–0.503) | 1 | 2.609 (2.159–3.154) | 4.599 (3.667–5.767) | ||
| post-term pregnancy | ||||||
| % (n) | 0.16% (n = 28) | 0.24% (n = 169) | 0.41% (n = 31) | 0.57% (n = 16) | <0.001 | |
| ORj (95%CIk) | 0.623 (0.431–0.901) | 1 | 1.879 (1.250–2.824) | 2.524 (1.546–4.120) |
aBMI, body mass index
bPIH, pregnancy-induced hypertension
cGDM, gestational diabetes mellitus
dSGA, small for gestational age
eLGA, large for gestational age
fPPROM, preterm prelabor rupture of membranes
gC/S,cesarian section
hPPH,postpartum hemorrhage
iVD,Vaginal delivery
jOR, odds ratio
kCI, confidence interval
Logistic regression was used to adjust for confounding variables, including maternal age, maternal height and parity, and generalized estimating equations (GEE) for logistic regression was used to adjust for the clustering of deliveries by hospitals. The results were expressed as odds ratios (OR) and 95% confidence intervals (CI).