Table 2: Obstetric risk factors.

Obstetric risk factors
Non-acidaemia
pH > 7.20 (N = 294)
Acidaemia
pH < 7.20 (N = 294)
Missing %p-valueOdds ratios (95% CI)

Past medical historyPre-gestational diabetes (PGDM)2 (1.1%)10 (5.3%)39.3%0.0185.31 (1.15 - 24.58)
Thyroid disease10 (5.5%)15 (8.4%)38.4%0.2741.58 (0.69 - 3.62)
Rheumatological disease0 (0.0%)5 (2.8%)39.1%0.0610.99 (0.97 - 0.99)
Cardiac disease17 (9.2%)11 (6.1%)38.3%0.2690.64 (0.29 - 1.76)
Asthma40 (21.4%)41 (22.4%)37.1%0.8141.06 (0.65 - 1.74)

Past obstetric historyCaesarean section38 (20.1%)37 (19.8%)36.1%0.9380.98 (0.59 - 1.63)
Preterm8 (4.4%)8 (4.5%)38.9%0.9361.04 (0.38 - 2.84)
Stillbirth5 (2.8%)3 (1.7%)39.1%0.7240.61 (0.14 - 2.58)
Miscarriage57 (29.8%)50 (27.2%)36.2%0.5670.88 (0.56 - 1.37)

Prenatal risksSmoking35 (13.9%)33 (11.6%)8.8%0.4120.81 (0.49 - 1.35)
Other recreational drugs12 (6.2%)19 (9.5%)33.0%0.2331.58 (0.74 - 3.34)
Anaemia50 (27.2%)52 (28.1%)37.2%0.8411.05 (0.66 - 1.65)
Urinary tract infection (UTI)12 (6.6%)34 (18.5%)37.76%0.0013.21 (1.61 - 6.43)
Pre-eclampsia35 (18.9%)50 (27.3%)37.80%0.0561.61 (0.99 - 2.63)
Antepartum haemorrhage (APH)16 (8.6%)11 (6.1%)37.93%0.3700.70 (0.31 - 1.54)
GDM (Gestational diabetes mellitus)14 (7.7%)11 (6.1%)38.27%0.5630.79 (0.35 - 1.78)
Obstetric cholestasis5 (2.8%)8 (4.5%)38.95%0.3801.66 (0.53 - 5.16)
IUGR (Intrauterine growth restriction)19 (10.3%)7 (4.0%)38.6%0.6290.36 (0.15 - 0.87)
RFM (Reduced Foetal Movement)42 (22.6%)56 (29.8%)36.4%0.1131.46 (0.91 - 2.32)

Obstetric risk factors for acidaemia where the cutoff for acidaemia is pH = 7.20. Binary logistic regression was performed for all variables.