Table 3 aORs and 95% CIs for intrapartum foetal acidosis by pre-pregnancy BMI after stratification based on mode of delivery.

From: Maternal pre-pregnancy body mass index and foetal acidosis in vaginal and caesarean deliveries: The Japan Environment and Children’s Study

Mode of delivery

BMI category (kg/m2)

G1

G2

G3

G4

G5

 < 18.5

18.5 to < 20.0

20 to < 23.0

23.0 to < 25.0

 ≥ 25.0

For UmA-pH < 7.20

Vaginal delivery (n = 58,345)

n = 9321

n = 14,752

n = 22,703

n = 5942

n = 5627

 aOR (95% CI)

0.93 (0.84–1.02)

0.90 (0.83–0.98)

Ref

1.03 (0.91–1.15)

1.12 (1.08–1.35)

Caesarean section (n = 13,454)

n = 1614

n = 2666

n = 5132

n = 1708

n = 2334

 aOR (95% CI)

1.04 (0.81–1.33)

0.82 (0.66–1.02)

Ref

1.07 (0.84–1.36)

1.06 (0.86–1.32)

For UmA-pH < 7.10

Vaginal delivery (n = 58,345)

n = 9321

n = 14,752

n = 22,703

n = 5942

n = 5627

 aOR (95% CI)

0.79 (0.63–1.01)

0.80 (0.65–0.98)

Ref

0.92 (0.70–1.22)

1.12 (0.86–1.46)

Caesarean section (n = 13,454)

n = 1614

n = 2666

n = 5132

n = 1708

n = 2334

 aOR (95% CI)

1.10 (0.70–1.75)

1.10 (0.74–1.62)

Ref

1.20 (0.77–1.89)

1.01 (0.66–1.55)

  1. Logistic regression models were used to calculate the adjusted odds ratios and 95% CIs for UmA-pH < 7.20 and < 7.10, using G3 as the reference group.
  2. aOR, adjusted odds ratio; BMI, body mass index; CI, confidence interval; Ref., reference; UmA-pH, umbilical artery pH.
  3. Model adjusted for maternal age, maternal education, annual household income, maternal smoking during pregnancy, parity, preterm birth, and small for gestational age infants.
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