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Table 1 Maternal and newborn characteristics for all women, and respondents versus no survey returned

From: Pre-notification letter type and response rate to a postal survey among women who have recently given birth

Characteristics

Study cohort

Respondents

No survey

p-value*

Univariate odds ratio

 

N = 1989 (%)

N = 913 (%)

N = 1076 (%)

 

(95 % CI)a

Maternal age (years)

     

 ≤24

233 (11.7)

66 (7.2)

167 (15.5)

p < 0.0001

0.50 (0.36–0.71)

 25–29

487 (24.5)

214 (23.4)

273 (25.4)

 

Reference

 30–34

750 (37.7)

362 (39.7)

388 (36.1)

 

1.19 (0.95–1.50)

 ≥35

519 (26.1)

271 (29.7)

248 (23.1)

 

1.39 (1.09–1.79)

Country of birth

     

 Australia

1196 (60.1)

559 (61.2)

637 (59.2)

p = 0.4

Reference

 Other

793 (39.9)

354 (38.8)

439 (40.8)

 

0.92 (0.77–1.10)

Socio-economic index

     

 1 (lowest)

107 (5.4)

30 (3.3)

77 (7.2)

p < 0.0001

0.34 (0.22–0.53)

 2

395 (19.9)

142 (15.6)

253 (23.5)

 

0.49 (0.39–0.63)

 3

169 (8.5)

66 (7.2)

103 (9.6)

 

0.56 (0.40–0.79)

 4

463 (23.3)

220 (24.1)

243 (22.6)

 

0.80 (0.64–1.00)

 5 (highest)

855 (43.0)

455 (49.8)

400 (37.2)

 

Reference

Maternity unit

     

 1

37 (1.9)

16 (1.8)

21 (2.0)

p < 0.0001

1.37 (0.70–2.67)

 2

674 (33.9)

241 (26.4)

433 (40.2)

 

Reference

 3

585 (29.4)

280 (30.7)

305 (28.4)

 

1.65 (1.32–2.07)

 4

29 (1.5)

17 (1.9)

12 (1.1)

 

2.55 (1.20–5.42)

 5

245 (12.3)

133 (14.6)

112 (10.4)

 

2.13 (1.59–2.87)

 6

149 (7.5)

75 (8.2)

74 (6.9)

 

1.82 (1.27–2.60)

 7

270 (13.6)

151 (16.5)

119 (11.1)

 

2.28 (1.71–3.04)

Parity

     

 Nulliparous

923 (46.4)

460 (50.4)

463 (43.0)

p = 0.001

1.34 (1.13–1.61)

 Multiparous

1066 (53.6)

453 (49.6)

613 (57.0)

 

Reference

Maternal smoking in pregnancy

140 (7.0)

25 (2.7)

115 (10.7)

p < 0.0001

0.24 (0.15–0.37)

Maternal BMI

     

 ≤25

1283 (64.5)

609 (66.7)

674 (62.6)

p = 0.1

Reference

 >25, ≤ 30

438 (22.0)

193 (21.1)

245 (22.7)

 

0.87 (0.70–1.10)

 >30

268 (13.5)

111 (12.2)

157 (14.6)

 

0.78 (0.60–1.02)

Multiple pregnancy

28 (1.4)

13 (1.4)

15 (1.4)

p = 1.0

1.02 (0.48–2.16)

Mode of birth

     

 Vaginal

1148 (57.7)

530 (58.1)

618 (57.5)

p = 0.1

Reference

 Instrumental

244 (12.3)

126 (13.8)

118 (11.0)

 

1.25 (0.94–1.64)

 Pre-labour caesarean

309 (15.5)

128 (14.0)

181 (16.8)

 

0.95 (0.73–1.23)

 Intrapartum caesarean

288 (14.5)

129 (14.1)

159 (14.8)

 

0.83 (0.64–1.06)

Postnatal length of stay (average days)

2.4

2.4

2.4

p = 1.0

-

Gestational age at birth (completed weeks)

     

 <37

136 (6.8)

61 (6.6)

75 (7.0)

p = 0.8

0.96 (0.67–1.36)

 ≥37

1853 (93.2)

852 (93.4)

1001 (93.1)

 

Reference

Infant gender

     

 Male

1024 (51.5)

456 (50.0)

568 (52.8)

p = 0.2

0.89 (0.75–1.07)

 Female

965 (48.5)

457 (50.1)

508 (47.2)

 

Reference

Infant admission to intensive care or special care nursery

324 (16.4)

132 (14.6)

192 (18.0)

p = 0.04

0.78 (0.61–0.99)

  1. *Chi-square test of comparison between Respondents and No Survey groups
  2. aOdds ratios for Respondents versus No Survey