Table 1 Comparison of participant characteristics between groups classified by severity of nausea and vomiting of pregnancy
|  | No vomiting (n = 296) | Mild-Moderate vomiting (n = 686) | Severe vomiting (n = 123) | Severe vomiting with hospitalisation (n = 67) | p- value | ||||
Maternal | |||||||||
Age at delivery, years (median, IQR) | 31.2 (27.8, 35.2) | 31.1 (27.5, 34.9) | 31.6 (27.6, 34.7) | 30.3 (26.4, 34.3) | 0.59 | ||||
Ethnicity (n, %) | |||||||||
 Chinese (n = 662) | 172 (26.0%) | 399 (60.3%) | 70 (10.6%) | 21 (3.2%) | < 0.001* | ||||
 Malay (n = 298) | 67 (22.5%) | 182 (61.1%) | 27 (9.1%) | 22 (7.4%) | |||||
 Indian (n = 212) | 57 (26.9%) | 105 (49.5%) | 26 (12.3%) | 24 (11.3%) | |||||
Pre-pregnancy BMI, kg/m2 (median, IQR) | 22.0 (19.6, 25.1) | 21.3 (19.4, 24.8) | 21.5 (19.4, 24.9) | 22.6 (20.4, 26.5) | 0.10 | ||||
Maternal Height, cm (mean, SD) | 158.3 (5.3) | 158.3 (5.6) | 157.6 (5.9) | 158.5 (5.7) | 0.82 | ||||
Parity (n, %) | |||||||||
 Nulliparous (n = 544) | 153 (28.1%) | 317 (58.3%) | 51 (9.4%) | 23 (4.2%) |  | ||||
 Parous (n = 628) | 143 (22.8%) | 369 (58.8%) | 72 (11.5%) | 44 (7.0%) | 0.03* | ||||
Education level (n, %) | |||||||||
 University (n = 396) | 100 (25.3) | 245 (61.9) | 37 (9.3) | 14 (3.5) | 0.27 | ||||
 Post-secondary/Pre-university (n = 291) | 69 (23.7) | 170 (58.4) | 32 (11.0) | 20 (6.9) | |||||
 Secondary or below (n = 470) | 125 (26.6) | 261 (55.5) | 52 (11.1) | 32 (6.8) | |||||
Maternal smoking# (n, %) | 42 (23.3) | 110 (61.1) | 15 (8.3) | 13 (7.2) | 0.50 | ||||
Child sex (n, %) | |||||||||
 Boys (n = 609) | 157 (25.8%) | 374 (61.4%) | 50 (8.2%) | 28 (4.6%) | 0.014* | ||||
 Girls (n = 563) | 139 (24.7%) | 312 (55.4%) | 73 (13.0%) | 39 (6.9%) |  | ||||
Weight change from preconception (kg) | |||||||||
|  | median (IQR) | β (95%CI) | median (IQR) | β (95% CI) | median (IQR) | β (95% CI) | median (IQR) | β (95% CI) |  |
14 weeks’ gestation | 2.65 (0.90, 4.75) | Ref | 2.15 (0.57, 4.12) | −0.34 (−0.99, 0.30) | 1.20 (0.55, 3.50) | −0.90 (−1.89, 0.08) | − 0.40 (−2.50, 2.10) | −2.80 *(− 4.17, −1.43) |  |
20 weeks’ gestation | 5.95 (3.90, 8.17) | Ref | 5.20 (3.40, 7.50) | − 0.40 (− 1.01, 0.19) | 4.20 (2.20, 6.60) | −1.33 *(− 2.30, − 0.36) | 4.40 (0.70, 5.55) | −2.39 *(−3.72, − 1.07) |  |
34 weeks’ gestation | 11.60 (8.97, 14.85) | Ref | 11.35 (8.60, 14.37) | −0.23 (− 0.98, 0.52) | 10.60 (7.90, 13.80) | 0.37 (− 1.55, 0.80) | 10.20 (6.52, 14.47) | −1.61 *(− 3.16, − 0.05) |  |