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Table 3 Frequency rate and adjusted odds ratios for adverse perinatal outcomes during second pregnancy in relation to change in BMI from first pregnancy for women with BMI (a) less than 25 and (b) more than 25 units in first pregnancy

From: Inter-pregnancy weight change impacts placental weight and is associated with the risk of adverse pregnancy outcomes in the second pregnancy

  

BMI change

 

(a) First pregnancy BMI <25, complication 2ndpregnancy (cases)

 

<−1†

−1 to <1

1 to <3

≥3

Trend¥, P value

Pre-eclampsia

Rate (%)

1.02

0.76

0.98

1.35

>0.1

(n = 75)

OR (95% CI)

1.43 (0.64-3.20)

1

1.14 (0.66-1.98)

1.27 (0.60-2.68)

>0.1

Gestational hypertension (n = 282)

Rate (%)

2.86

3.04

3.86

5.52

<0.001

OR (95% CI)

0.87 (0.54-1.39)

1

1.30 (0.99-1.73)

1.98 (1.35-2.90)***

0.002

Emergency caesarean

Rate (%)

3.67

2.24

3.43

8.06

<0. 001

(n = 267)

OR (95% CI)

1.73 (1.11-2.69)*

1

1.41 (1.03-1.92)*

2.64 (1.82-3.81)***

<0.001

Spontaneous preterm (<37 wks, n = 402)

Rate (%)

7.47

4.78

5.05

4.78

>0.1

OR (95% CI)

1.89 (1.30-2.74)***

1

0.62 (0.38-1.02)

0.62 (0.38-1.02)

<0.001

SGA, <10th C

Rate (%)

12.36

7.33

7.05

6.52

0.001

(n = 585)

OR (95% CI)

1.76 (1.35-2.28)***

1

0.90 (0.74-1.11)

0.69 (0.50-0.96)*

<0.001

LGA, >90th C

Rate (%)

1.80

3.90

6.96

6.15

<0. 001

(n = 381)

OR (95% CI)

0.44 (0.25-0.76)**

1

1.84 (1.46-2.32)***

1.83 (1.28-2.60)***

<0.001

Placental wt. <10thC

Rate (%)

11.40

7.24

6.54

6.90

0.005

(n = 568)

OR (95% CI)

1.79 (1.36-2.34)***

1

0.92 (0.74-1.13)

1.05 (0.76-1.44)

<0.001

Placental wt. >90thC

Rate (%)

4.49

5.94

9.08

11.69

<0. 001

(n = 564)

OR (95% CI)

0.69 (0.47-1.00)*

1

1.49 (1.22-1.82)***

1.76 (1.33-2.32)***

<0.001

(b) First pregnancy BMI >25, complication 2 nd pregnancy (cases)

      

Pre-eclampsia

Rate (%)

1.20

0.68

1.69

2.81

<0.001

(n = 65)

OR (95% CI)

1.47 (0.60-3.63)

1

2.29 (1.06-4.95)*

3.03 (1.38-6.64)**

0.029

Gestational hypertension (n = 242)

Rate (%)

4.19

5.02

5.68

8.52

<0.001

OR (95% CI)

0.76 (0.50-1.17)

1

1.09 (0.77-1.54)

1.64 (1.14-2.36)**

0.004

Emergency caesarean

Rate (%)

3.80

4.07

4.89

5.52

0.063

(n = 194)

OR (95% CI)

0.88 (0.56-1.38)

1

1.14 (0.78-1.65)

1.11 (0.73-1.69)

>0.1

Spontaneous preterm (<37 wks, n = 156)

Rate (%)

4.44

3.34

3.52

3.41

>0.1

OR (95% CI)

1.01 (0.60-1.69)

1

0.97 (0.60-1.56)

0.67 (0.38-1.19)

>0.1

SGA, <10th C

Rate (%)

7.09

3.99

4.89

5.14

>0.1

(n = 215)

OR (95% CI)

1.73 (1.18-2.54)**

1

1.18 (0.81-1.72)

1.13 (0.74-1.73)

0.036

LGA, >90th C

Rate (%)

5.09

9.04

9.43

12.98

<0. 001

(n = 374)

OR (95% CI)

0.55 (0.38-0.79)***

1

1.05 (0.80-1.38)

1.45 (1.08-1.95)*

<0.001

Placental wt. <10thC

Rate (%)

6.81

4.36

4.28

4.39

0.049

(n = 205)

OR (95% CI)

1.56 (1.07-2.29)*

1

0.91 (0.62-1.33)

0.93 (0.60-1.44)

0.026

Placental wt. >90thC

Rate (%)

11.31

12

11.25

16.42

0.023

(n = 497)

OR (95% CI)

0.91 (0.69-1.20)

1

0.94 (0.73-1.20)

1.34 (1.03-1.75)*

0.029

  1. Odds ratios (OR) and 95% confidence limits (CI) from logistic regression *P < 0.05, **P < 0.01 ***P < 0.001 relative to stable BMI reference group (OR = 1). Models adjusted for baseline BMI at first pregnancy, height and inter-delivery interval, and maternal age, year of delivery and smoking status, gestational age and baby gender at second pregnancy. Where appropriate, variables were additionally adjusted for the co-occurrence of pre-eclampsia or gestational hypertension. For each individual endpoint women experiencing the complication in the first pregnancy were excluded. For the < −1, -1 to 1, 1 to 3 and ≥3 BMI change categories the distribution of the study population was 9, 50, 30 and 11% for women with a first pregnancy BMI of less than 25 (a) and 19, 33, 28 and 20% for women with a first pregnancy BMI of more than 25 (b). † Refers to BMI loss between pregnancies of more than 1 unit. ¥Significance of trend for complication frequency rate from the Cochran –Armitage test and for odds ratios from calculation of overall Chi square value. SGA, Small for gestational age; LGA, Large for gestational age. Birth and placental weight categories based on gender and parity specific centile charts for Scotland [26, 27].
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BMC Pregnancy and Childbirth

ISSN: 1471-2393

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