Table 1 Characteristics of the study population (n = 566) at the time of conception and at 20 weeks of gestation
At the time of conception | At 20 weeks of gestation | |||||||
|---|---|---|---|---|---|---|---|---|
Total | Smokers | Never smokers | P-value* | Smokers | Quitters | Never smokers | P-value* | |
n | n (%) | n (%) | n (%) | n (%) | n (%) | |||
Overall respondents | 566 | 90 (16) | 476 (84) | 35 (6) | 55 (10) | 476 (84) | ||
Age (years) | 0.002 | 0.01 | ||||||
18–24 | 55 | 17 (31) | 38 (69) | 7 (13) | 10 (18) | 38 (69) | ||
25–29 | 184 | 35 (19) | 149 (81) | 12 (7) | 23 (12) | 149 (81) | ||
30–34 | 205 | 25 (12) | 180 (88) | 9 (4) | 16 (8) | 180 (88) | ||
≥ 35 | 122 | 13 (11) | 109 (89) | 7 (6) | 6(5) | 109 (89) | ||
Mean age (SD) | 30.5 | 29 (5.2) | 30.8 (4.8) | 0.002 | 29.7 | 28.6 | 30.8 (4.8) | 0.004 |
Missing data 0 | ||||||||
BMI (kg/m2) | 0.015 | 0.31 | ||||||
Underweight (< 18.5) | 19 | 8 (42) | 11 (58) | 3 (16) | 5 (26) | 11 (58) | ||
Normal (18.5–24.9) | 302 | 45 (15) | 257 (85) | 17 (6) | 28 (9) | 257 (85) | ||
Overweight (25–29.9) | 134 | 22 (16) | 112 (84) | 11 (8) | 11 (8) | 112 (84) | ||
Obese (≥ 30) | 64 | 8 (12) | 56 (88) | 4 (6) | 4 (6) | 56 (88) | ||
Mean BMI (SD) | 24.4 | 24.8 (4.5) | 24.3 (4.7) | 25.0 (4.7) | 24.6 (4.5) | 24.3 (4.7) | 0.33 | |
Missing data 47 | ||||||||
Parity | 0.04 | 0.02 | ||||||
Nullipara | 222 | 44 (20) | 178 (80) | 13 (6) | 31(14.0) | 178 (80) | ||
Multipara | 343 | 46 (13) | 297 (87) | 22 (6) | 24 (7) | 297 (87) | ||
Missing data 1 | ||||||||
Mode of conception | 0.21 | 0.29 | ||||||
Spontaneous | 504 | 83 (16) | 421 (84) | 34 (7) | 49 (10) | 421 (83) | ||
Assisted reproductive technologies | 59 | 6 (10) | 53 (90) | 1 (2) | 5 (8) | 53 (90) | ||
Missing data 3 | ||||||||
Chronic illnessa | 0.90 | 0.94 | ||||||
Yes | 104 | 17 (16) | 87 (84) | 6 (6) | 11 (10) | 87 (84) | ||
No | 462 | 73 (16) | 389 (84) | 29 (6) | 44 (10) | 389 (84) | ||
Missing data 0 | ||||||||
Self-rated general health | 0.11 | 0.14 | ||||||
Good | 411 | 62 (15) | 349 (85) | 21 (5) | 41 (10) | 349 (85) | ||
Moderate | 119 | 18 (15) | 101 (85) | 9 (8) | 9(8) | 101 (84) | ||
Poor | 35 | 10 (29) | 25 (71) | 5 (14) | 5(14) | 25 (72) | ||
Missing data 1 | ||||||||
Education | < 0.001 | < 0.0001 | ||||||
≤ 12 years | 101 | 30 (30) | 71 (70) | 17 (17) | 13 (13) | 71 (70) | ||
> 12 years | 463 | 60 (13) | 403 (87) | 18 (4) | 42 (9) | 403 (87) | ||
Missing data 2 | ||||||||
Work schedule | 0.001 | 0.002 | ||||||
Day time | 465 | 63 (13) | 402 (87) | 22 (5) | 41 (9) | 402 (86) | ||
Shift work | 101 | 27 (27) | 74 (73) | 13 (13) | 14 (14) | 74 (73) | ||
Missing data 0 | ||||||||
Employment status | < 0.001 | < 0.0001 | ||||||
Employed | 509 | 71 (14) | 438 (86) | 24 (5) | 47 (9) | 438 (86) | ||
Unemployed | 57 | 19 (33) | 38 (67) | 11 (19) | 8 (14) | 38 (67) | ||
Missing data 0 | ||||||||
Cohabitation | 0.008 | < 0.0001 | ||||||
Yes | 526 | 77 (15) | 449 (85) | 26 (5) | 51 (10) | 449 (85) | ||
No | 39 | 12 (31) | 27 (69) | 8 (21) | 4 (10) | 27 (69) | ||
Missing data 1 | ||||||||
Cigarettes per dayb | ||||||||
1–9 cigarettes | N/A | 24 (29) | N/A | – | N/A | N/A | – | |
≥10 cigarettes | N/A | 60 (71) | N/A | – | N/A | N/A | – | |
Missing data 6 | ||||||||