0–8 weeks | 24/85 | 28.2 | | 134/292 | 45.9 |
9–14 weeks | 35/85 | 41.2 | | 173/354 | 48.9 |
15–22 weeks | 35/75 | 46.7 | | 162/301 | 53.8 |
23 weeks or older | 30/68 | 44.1 | | 195/349 | 55.9 |
χ2test for trend | p < 0.05 | | p < 0.001 |
Test for departure from linearity | 0.25 > p > 0.10 | | 0.90 > p > 0.75 |
Mantel-Haenszel | p < 0.001 |
| |
Socioeconomic status
|
n
|
%
| |
n
|
%
|
V or never employed | 34/67 | 50.7 | | 61/92 | 66.3 |
III or IV | 74/197 | 37.6 | | 409/759 | 53.9 |
I or II | 16/48 | 33.3 | | 193/442 | 43.7 |
χ2 test for trend | p < 0.05 | | p < 0.001 |
Test for departure from linearity | 0.50 > p > 0.25 | | 0.90 > p > 0.75 |
Mantel-Haenszel | p < 0.001 |
| |
Duration of breast feeding4-160
|
n
|
%
| |
n
|
%
|
Never attempted | 81/179 | 45.3 | | 319/522 | 61.1 |
1–2 weeks | 16/40 | 40.0 | | 100/169 | 59.2 |
3–6 weeks | 13/41 | 31.7 | | 92/189 | 48.7 |
7–12 weeks | 8/29 | 27.6 | | 81/203 | 39.9 |
More than 12 weeks | 6/24 | 25.0 | | 71/212 | 33.5 |
χ2 test for trend | p < 0.01 | | p < 0.001 |
Test for departure from linearity | 0.75 > p > 0.50 | | 0.25 > p > 0.10 |
Mantel-Haenszel | p < 0.001 |
| |
Maternal smoking
|
n
|
%
| |
n
|
%
|
Does not smoke | 33/103 | 32.0 | | 450/929 | 48.4 |
1–9 cigarettes | 30/85 | 35.3 | | 76/157 | 48.4 |
10–19 cigarettes | 38/70 | 54.3 | | 94/144 | 65.3 |
20 or more cigarettes | 23/55 | 41.8 | | 44/65 | 67.7 |
χ2 test for trend | p < 0.025 | | p < 0.001 |
Test for departure from linearity | 0.10 > p > 0.05 | | 0.25 > p > 0.10 |
Mantel-Haenszel | p < 0.001 |