Table 4.

Adjusted odds ratios^a and 95% confidence intervals for foetal acidosis based on gestational weight gain with vaginal deliveries according to Japanese criteria²⁸.

BMI category (kg/m2)	Gestational weight gain
	Insufficient	Appropriate	Excessive
UmA-pH < 7.2
Group 1; BMI < 18.5 (n = 9321)	n = 4664	n = 2871	n = 1786
aOR (95% CI)	0.85 (0.70–1.04)	Ref	1.03 (0.81–1.30)
Group 2; BMI 18.5–< 20.0 (n = 14,752)	n = 5261	n = 5294	n = 4197
aOR (95% CI)	0.97 (0.83–1.15)	Ref	1.12 (0.94–1.32)
Group 3; BMI 20.0–< 23.0 (n = 22,703)	n = 5807	n = 8099	n = 8797
aOR (95% CI)	0.95 (0.82–1.08)	Ref	1.00 (0.88–1.12)
Group 4; BMI 23.0–< 25.0 (n = 5942)	n = 802	n = 2015	n = 3125
aOR (95% CI)	0.84 (0.58–1.22)	Ref	1.31 (1.04–1.62)
Group 5; BMI ≥ 25 (n = 5627)	n = 597	n = 1767	n = 3263
aOR (95% CI)	0.82 (0.57–1.19)	Ref	0.97 (0.78–1.21)
UmA-pH < 7.1
Group 1; BMI < 18.5 (n = 9321)	n = 4664	n = 2871	n = 1786
aOR (95% CI)	1.30 (0.78–2.16)	Ref	1.49 (0.81–2.74)
Group 2; BMI 18.5–< 20.0 (n = 14,752)	n = 5261	n = 5294	n = 4197
aOR (95% CI)	1.04 (0.69–1.57)	Ref	1.46 (0.97–2.18)
Group 3; BMI 20.0–< 23.0 (n = 22,703)	n = 5807	n = 8099	n = 8797
aOR (95% CI)	0.83 (0.60–1.14)	Ref	0.96 (0.73–1.26)
Group 4; BMI 23.0–< 25.0 (n = 5942)	n = 802	n = 2015	n = 3125
aOR (95% CI)	1.42 (0.59–3.42)	Ref	2.08 (1.13–3.83)
Group 5; BMI ≥ 25 (n = 5627)	n = 597	n = 1767	n = 3263
aOR (95% CI)	0.29 (0.09–0.97)	Ref	0.80 (0.49–1.31)

Logistic regression models were used to calculate the adjusted odds ratios and 95% confidence intervals for UmA-pH < 7.20 and for UmA-pH < 7.10, with women with appropriate gestational weight gain as the reference. BMI body mass index, UmA-pH umbilical artery pH.

^aAdjusted for maternal age, maternal education, annual household income, maternal smoking during pregnancy, parity, preterm birth and small-for-gestational age infants.