Table 1 Descriptive characteristics of mothers, infants and neighbourhoods according to adverse birth outcomes, singleton births, Montréal, 1997–2001

Characteristics	PTB*	Total	LBW†	Total	SGA‡	Total
Characteristics	%	n	%	n	%	n
Mothers
Proximity to highway
<200 m	7.0	5927	5.3	5925	9.8	5923
⩾200 m	6.3	93 251	4.6	93 255	9.1	93 164
Age (years)
<20	8.6	3989	6.9	3991	12.4	3982
20–34	6.0	77 095	4.4	77 099	9.0	77 033
⩾35	7.1	18 094	5.2	18 090	8.9	18 072
Education
Less than high school graduation	8.1	15 859	6.4	15 862	11.8	15 843
High school graduation	7.3	10 987	5.2	10 988	10.2	10 982
Some college or preuniversity	6.7	21 658	5.1	21 664	9.7	21 635
Some university or better	5.4	50 656	3.7	50 648	7.9	50 609
Marital status
Legally married	5.7	59 754	4.0	59 750	8.6	59 716
Other	7.2	39 424	5.5	39 430	10.1	39 371
Country of birth
Canada	6.1	54 713	4.4	54 716	8.6	54 672
Other	6.6	44 465	5.0	44 464	9.8	44 415
History of prior stillbirth
No	6.2	96 337	4.6	96 338	9.2	96 251
Yes	9.2	2841	7.1	2842	9.5	2836
Infants
Birth order
Firstborn	6.9	47 067	5.4	47 071	11.2	47 012
Other	5.7	52 111	3.9	52 109	7.4	52 075
Sex
Male	6.7	51 005	4.3	51 006	9.3	50 954
Female	5.9	48 173	5.0	48 174	9.1	48 133
Year of birth
1997	6.0	20 607	4.9	20 615	9.9	20 588
1998	6.6	19 874	5.0	19 871	9.8	19 851
1999	6.4	19 535	4.5	19 531	8.9	19 510
2000	6.4	19 451	4.5	19 450	8.5	19 438
2001	6.2	19 711	4.2	19 713	8.7	19 700
Neighbourhoods
% low-income families
Q1 (poorest)	7.1	22 925	5.7	22 928	10.9	22 906
Q2	6.8	19 678	4.8	19 678	9.5	19 657
Q3	6.6	18 819	4.7	18 824	9.0	18 800
Q4	6.0	18 381	4.2	18 379	8.8	18 363
Q5 (richest)	4.9	19 375	3.4	19 371	7.3	19 361
Total	6.3	99 178	4.6	99 180	9.2	99 087