Socioeconomic disparities in prepregnancy BMI and impact on maternal and neonatal outcomes and postpartum weight retention: the EFHL longitudinal birth cohort study

Table 1 Baseline characteristics of the cohort and comparisons with all births in the study region (with gestational 28 weeks or more)

Characteristics	Frequency (percentage^a)
Characteristics	Birth cohort sample (Years 2007 to 2010) 2254 women 2277 babies	Deliveries in region^b(Years 2007 to 2010) 36620 women 37061 babies	p-value^c(two-sided)
Maternal age
< 20 years	107 (4.8%)	2559 (7.0%)	< 0.001
20-24 years	438 (19.9%)	6407 (17.6%)
25-29 years	632 (28.6%)	10376 (28.5%)
30-34 years	560 (25.4%)	10088 (27.7%)
≥ 35 years	469 (21.3%)	6980 (19.2%)
Missing data	48	0
Gender of infant
Male	1127 (50.3%)	18914 (51.3%)	0.324
Female	1115 (49.7%)	17926 (48.7%)
Missing data	35	0
Birthweight
< 2500 g	55 (2.5%)	1800 (4.9%)	< 0.001
2500-3999 g	1809 (81.5%)	30207 (82.0%)
≥ 4000 g	355 (16.0%)	4831 (13.1%)
Missing data	58	2
Gestational age at birth
28-36 weeks	79 (3.5%)	2376 (6.4%)	< 0.001
37-41 weeks	2131 (95.9%)	34264 (93.0%)
42 weeks	13 (0.6%)	200 (0.5%)
Missing data	54	0
Plurality
Singleton	2207 (98.0%)	35980 (97.7%)
Multiple	46 (2.0%)	860 (2.3%)	0.370
Missing data	24	0
Outcome
Live birth	2273 (99.8%)	36728 (99.7%)
Stillbirth	4 (0.2%)	112 (0.3%)	0.274
Missing data	0	0

^aPercentages are calculated based on the available (non-missing) data.
^bData include only deliveries with gestational 28 weeks or more; data are provided by Queensland Health and New South Wales Health for the study region (Logan, Beaudesert, Gold Coast and Tweed).
^cChi-square test for comparing proportions between birth cohort sample and the general population.

ISSN: 1471-2393