Table 3 Model results (odds ratios) for maternal outcomes by category of pre-pregnancy body mass index and gestational weight gain

Gestational weight gain

<  5 kg

5–9 kg

>  9 kg

<  5 kg

5–9 kg

>  9 kg

<  5 kg

5–9 kg

>  9 kg

Gestational diabetes

3.5 (3.4, 3.5)^a

3.3 (3.3, 3.4) ^a

2.5 (2.5, 2.5) ^a

4.3 (4.2, 4.3) ^a

4.0 (3.9, 4.0) ^a

3.3 (3.2, 3.3) ^a

5.3 (5.2, 5.4) ^a

4.7 (4.6, 4.8) ^a

4.3 (4.2, 4.4) ^a

Gestational hypertension

2.1 (2, 2.1) ^a

2.5 (2.5, 2.6) ^a

3.8 (3.8, 3.9) ^a

3.0 (2.9, 3.0) ^a

3.6 (3.6, 3.7) ^a

5.3 (5.2, 5.3) ^a

4.5 (4.4, 4.5) ^a

5.4 (5.3, 5.5) ^a

7.3 (7.2, 7.4) ^a

Eclampsia

2.0 (1.8, 2.2) ^a

2.1 (1.9, 2.3) ^a

3.4 (3.2, 3.6) ^a

2.5 (2.3, 2.8) ^a

2.9 (2.6, 3.2) ^a

4.6 (4.3, 4.9) ^a

3.5 (3.2, 3.9) ^a

4.6 (4.1, 5.0) ^a

6.1 (5.7, 6.5) ^a

Labor induction

1.2 (1.2, 1.2) ^a

1.3 (1.3, 1.3) ^a

1.4 (1.4, 1.4) ^a

1.4 (1.4, 1.4) ^a

1.5 (1.5, 1.5) ^a

1.5 (1.5, 1.5) ^a

1.6 (1.6, 1.6) ^a

1.6 (1.5, 1.6) ^a

1.6 (1.6, 1.6) ^a

Caesarian section

1.5 (1.5, 1.5) ^a

1.7 (1.7, 1.7) ^a

2.0 (2.0, 2.0) ^a

1.9 (1.8, 1.9) ^a

2.1 (2.1, 2.1) ^a

2.6 (2.5, 2.6) ^a

2.6 (2.6, 2.7) ^a

2.9 (2.9, 3.0) ^a

3.4 (3.4, 3.4) ^a

Maternal transfusion

1.3 (1.2, 1.4) ^a

1.2 (1.1, 1.3) ^a

1.2 (1.1, 1.2) ^a

1.2 (1.1, 1.4) ^a

1.1 (1.0, 1.3) ^a

1.2 (1.1, 1.3) ^a

1.3 (1.2, 1.4) ^a

1.2 (1.1, 1.4) ^a

1.3 (1.2, 1.5) ^a

Perineal laceration

0.5 (0.4, 0.5) ^b

0.5 (0.5, 0.5) ^b

0.6 (0.5, 0.6) ^b

0.4 (0.4, 0.4) ^b

0.4 (0.4, 0.4) ^b

0.4 (0.4, 0.5) ^b

0.3 (0.3, 0.3) ^b

0.3 (0.3, 0.4) ^b

0.3 (0.3, 0.3) ^b

Ruptured uterus

1.4 (1.1, 1.8) ^a

1.1 (0.9, 1.5)

1.3 (1.1, 1.5) ^a

1.4 (1.1, 1.8) ^a

1.1 (0.8, 1.5)

1.2 (1.0, 1.5) ^a

1.6 (1.2, 2.1) ^a

1.3 (0.9, 1.9)

1.4 (1.1, 1.8) ^a

Unplanned hysterectomy

1.8 (1.4, 2.1) ^a

1.7 (1.4, 2.1) ^a

1.5 (1.3, 1.8) ^a

1.5 (1.1, 1.9) ^a

1.3 (1.0, 1.7) ^a

1.6 (1.3, 1.9) ^a

1.9 (1.5, 2.3) ^a

1.7 (1.3, 2.3) ^a

1.9 (1.5, 2.3) ^a

Admission to ICU

1.4 (1.2, 1.5)

1.3 (1.1, 1.4) ^a

1.3 (1.3, 1.4) ^a

1.5 (1.3, 1.7) ^a

1.3 (1.1, 1.5) ^a

1.5 (1.4, 1.7) ^a

1.7 (1.5, 2.0) ^a

1.6 (1.4, 1.9) ^a

2.6 (2.4, 2.9) ^a