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Table 2 Frequency rate and adjusted odds ratios for adverse perinatal outcomes during second pregnancy in relation to change in BMI from first pregnancy (a) for women with specific complication in second pregnancy only and (b) for all women irrespective of first pregnancy history

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

  

BMI change (% study population)

 

(a) Complication 2ndpregnancy only (cases)

 

<−1†

−1 to <1

1 to <3

≥3

Trend¥, P value

  

(13%)

(44%)

(29%)

(14%)

 

Pre-eclampsia

Rate (%)

1.11

0.74

1.22

2.07

<0.001

(n = 140)

OR (95% CI)

1.23 (0.69-2.20)

1

1.44 (0.93-2.23)

1.85 (1.12-3.04)*

0.100

Gestational

Rate (%)

3.54

3.55

4.47

6.98

<0. 001

Hypertension (n = 524)

OR (95% CI)

0.83 (0.61-1.14)

1

1.22 (0.98-1.52)

1.82 (1.40-2.36)***

<0.001

Induced labour

Rate (%)

13.13

10.70

12.55

14.42

0.032

(n = 1371)

OR (95% CI)

1.21 (1.01-1.46)*

1

1.12 (0.98-1.29)

1.17 (0.97-1.40)

0.100

Elective caesarean

Rate (%)

7.34

7.01

8.56

9.69

0.001

(n = 930)

OR (95% CI)

0.91 (0.72-1.15)

1

1.16 (0.98-1.37)

1.18 (0.95-1.48)

0.093

Emergency caesarean

Rate (%)

3.74

2.72

3.92

6.79

<0. 001

(n = 461)

OR (95% CI)

1.27 (0.93-1.75)

1

1.30 (1.03-1.66)*

1.78 (1.35-2.35)***

<0.001

Spontaneous preterm

Rate (%)

5.89

4.39

4.53

4.1

0.072

(<37 wks, n = 558)

OR (95% CI)

1.46 (1.08-1.97)*

1

1.00 (0.78-1.28)

0.65 (0.45-0.93)*

0.002

SGA, <10th C

Rate (%)

9.57

6.42

6.31

5.83

<0.001

(n = 800)

OR (95% CI)

1.65 (1.33-2.04)***

1

0.95 (0.80-1.14)

0.82 (0.63-1.05)

<0.001

LGA, >90th C (n = 755)

Rate (%)

3.48

5.22

7.78

9.42

<0. 001

OR (95% CI)

0.57 (0.42-0.76)***

1

1.48 (1.24-1.76)***

1.70 (1.36-2.13)***

<0.001

Placental wt. <10thC

Rate (%)

8.25

6.06

5.45

5.34

<0. 001

(n = 773)

OR (95% CI)

1.67 (1.35-2.07)***

1

0.91 (0.76-1.09)

0.99 (0.77-1.28)

<0.001

Placental wt. >90thC

Rate (%)

7.33

6.96

8.93

12.27

<0. 001

(n = 1061)

OR (95% CI)

0.90 (0.72-1.11)

1

1.26 (1.08-1.47)**

1.59 (1.31-1.47)***

<0.001

(b) Complication all women (cases)

      

Pre-eclampsia

Rate (%)

1.68

1.27

1.93

3.31

<0. 001

(n = 225)

OR (95% CI)

0.97 (0.60-1.55)

1

1.33 (0.94-1.88)

1.70 (1.14-2.53)**

0.033

Gestational hypertension (n = 967)

Rate (%)

7.06

6.4

9.74

12.04

<0. 001

OR (95% CI)

0.90 (0.72-1.14)

1

1.50 (1.28-1.77)***

1.79 (1.46-2.20)***

<0.001

Induced labour

Rate (%)

23.27

20.1

24.45

29.71

<0. 001

(n = 2386)

OR (95% CI)

1.07 (0.92-1.24)

1

1.13 (1.01-1.26)*

1.20 (1.03-1.39)*

0.057

Elective caesarean

Rate (%)

9.06

8.68

10.06

11.48

0.004

(n = 1107)

OR (95% CI)

0.91 (0.74-1.13)

1

1.10 (0.94-1.29)

1.15 (0.93-1.41)

>0.1

Emergency caesarean

Rate (%)

7.69

6.24

7.74

10.65

<0. 001

(n = 885)

OR (95% CI)

1.08 (0.86-1.36)

1

1.12 (0.94-1.33)

1.24 (1.00-1.54)*

>0.1

Spontaneous preterm (<37 wks, n = 745)

Rate (%)

7.41

6.13

5.89

6.03

>0.1

OR (95% CI)

1.23 (0.90-1.67)

1

0.91 (0.71-1.16)

0.71 (0.50-1.01)

0.057

SGA, <10th C (n = 1203)

Rate (%)

14.55

10.52

9.29

8.88

<0. 001

OR (95% CI)

1.63 (1.36-1.95)***

1

0.85 (0.74-0.99)*

0.78 (0.63-0.97)*

<0.001

LGA, >90th C

Rate (%)

6.09

7.71

11.11

14.49

<0. 001

(n = 1093)

OR (95% CI)

0.64 (0.50-0.82)***

1

1.44 (1.23-1.67)***

1.82 (1.50-2.20)***

<0.001

Placental wt. <10thC

Rate (%)

9.95

8.3

6.89

6.41

<0. 001

(n = 999)

OR (95% CI)

1.53 (1.26-1.87)

1

0.84 (0.71-0.98)*

0.88 (0.70-1.11)

<0.001

Placental wt. >90thC

Rate (%)

9.89

9.47

11.87

16.54

<0. 001

(n = 1429)

OR (95% CI)

0.84 (0.69-1.01)

1

1.24 (1.08-1.42)**

1.59 (1.34-1.89)***

<0.001

  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 (a), women with each individual complication in the first pregnancy were excluded. † 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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