| Study | Study type | Population | Study period | End point | Smoking status | Relative risk (95% confidence interval) | Adjustment factors |
|---|---|---|---|---|---|---|---|
| Linn et al. 1982 | Survey on deliveries | 3,214 married nondiabetic women who gave birth after planned pregnancy United States | 1977-1979 | Relative risk for conception delay > 3 months | Nonsmokers Smokers | 1.0 1.0 (0.9-1.2) | Maternal: contraception use, age, history of spontaneous abortion, use of diethylstilbestrol (DES) by woman's mother, body mass index, marijuana use, age at menarche, race, religion, history of pelvic inflammatory disease, history of induced abortion or ectopic pregnancy, gravidity, education, welfare status |
| Olsen et al. 1983 | Case-control | Cases: 228 women attempting first pregnancy for >1 year Controls: 1,400 parous women who achieved first pregnancy in <1 year Denmark | 1977-1980 | Relative risk for conception delay > 12 months (first pregnancy) | Nonsmokers Smokers | 1.0 1.8 (1.3-2.5) | Maternal: age, education, parity, oral contraceptive use, alcohol consumption, residence |
| Cases: 195 parous women attempting pregnancy for > 1 year Controls: 1,800 parous women who achieved pregnancy in <1 year Denmark | Relative risk for conception delay > 12 months (second or later pregnancy) | Nonsmokers Smokers | 1.0 1.3 (1.0-1.8) | ||||
| Suonio et al. 1990 | Survey of pregnant women | 2,198 pregnant women who conceived in < 12
months Finland | 1983 | Relative risk for conception delay > 6 months | Nonsmokers Smokers | 1.0 1.5 (1.3-1.8) | Maternal: age, gravidity, spontaneous abortion, induced abortion, maternal alcohol consumption, occupation, working time, strain of work Paternal: smoking, alcohol consumption |
| Olsen 1991 | Survey | 10,886 pregnant women Denmark | 1984-1987 | Relative risk for conception delay >12 months | Smokers | Maternal: number of pregnancies, education, shift work, age, alcohol intake, coffee intake Paternal: age, smoking | |
| 1-4 cigarettes/day | 1.0 | ||||||
| 5-9 cigarettes/day | 1.8 (1.3-2.6) | ||||||
| 10-14 cigarettes/day | 1.8 (1.3-2.6) | ||||||
| 15-19 cigarettes/day | 1.8 (1.2-2.5) | ||||||
| > 20 cigarettes/day | 1.7 (1.2-2.5) | ||||||
| Laurent et al. 1992 | Case-control | Cases: 483 women with history of
conception delay > 24 months Controls: 2,231 women without conception delay > 24 months United States | 1980-1983 | Relative risk for conception delay > 24 months | Nonsmokers | 1.0 | Maternal: age, age at first sexual intercourse, education, ethnicity, history of benign ovarian disease |
| Smokers | |||||||
| 1-4 cigarettes/day | 1.0 (1.0-1.0) | ||||||
| 5-9 cigarettes/day | 1.1 (1.0-1.1) | ||||||
| 10-19 cigarettes/day | 1.2 (1.1-1.3) | ||||||
| > 20 cigarettes/day | 1.4 (1.1-1.6) | ||||||
| Bolumar et al. 1996 | Population survey of pregnancy history | 3,187 women with planned
pregnancy Europe | 1991-1993 | Relative risk for conception delay >9.5 months for first pregnancy | Nonsmokers | 1.0 | Maternal: age, education, recent oral contraceptive use, frequency of sexual intercourse, paid work, alcohol consumption, coffee consumption |
| Smokers | |||||||
| 1.4 (1.1-1.7) | 1-10 cigarettes/day | ||||||
| > 11 cigarettes/day | 1.7 (1.3-2.1) | ||||||
| Prenatal survey | 2,587 pregnant women with planned pregnancy Europe | 1991-1993 | Relative risk for conception delay >9.5 months for first pregnancy | Nonsmokers | 1.0 | ||
| Smokers | |||||||
| 1-10 cigarettes/day | 1.4 (1.0-1.8) | ||||||
| > 11 cigarettes/day | 1.7 (1.3-2.3) | ||||||
| Hull et al. 2000 | Population-based survey | 14,182 pregnant women who reached
24 weeks' gestation England | 1991-1992 | Relative risk for conception delay of >6 months * | Nonsmokers | Maternal: age, education, duration
of oral contraceptive use, alcohol consumption, housing
tenure and type, overcrowding Paternal: age, education, alcohol consumption | |
| Smokers | |||||||
| 1-4 cigarettes/day | 1.0 | ||||||
| 5-9 cigarettes/day | 1.2 (0.9-1.6) | ||||||
| 10-14 cigarettes/day | 1.2 (0.9-11.6) | ||||||
| 15-19 cigarettes/day | 1.5 (1.2-1.9) | ||||||
| > 20 cigarettes/day | 1.6 (1.3-2.0) |
Note: Relative risk for conception delay compares risks of waiting longer than a specified time; values >1.0 indicate impairment of fecundity.
Conception delay of >12 months was also examined, and results were similar.
From: Chapter 3. Health Consequences of Tobacco Use Among Women
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