Abstract

STUDY OBJECTIVE: To test the stress hypothesis by characterising women during their first pregnancy who continue to smoke in early pregnancy in comparison with women who quit smoking, with special reference to psychosocial factors like social network, social support, demands, and control in work and daily life. DESIGN: The study is based on a cohort of primigravidas followed during pregnancy. Data were collected by self administered questionnaires during the pregnant womens' first antenatal visit at about 12 weeks. SETTING: The study was performed in the antenatal clinics in the city of Malmö, Sweden. PARTICIPANTS: The participants were all primigravidas living in the city of Malmö, Sweden, over a one year period, 1991-92. A total of 872 (87.7%) of the 994 invited women agreed to participate. The population of this study on smoking includes all primigravidas who at the time of conception were smoking (n = 404, 46.3%). MAIN RESULTS: At the first antenatal visit (63.6% (n = 257) of the prepregnancy smokers were still smoking (a total smoking prevalence of 29.5%). The pregnant smokers were on average younger and had a lower educational level. The highest relative risk (RR) of continued smoking was found among unmarried women RR 2.7 (95% confidence interval) (1.5, 4.8), women having unplanned pregnancies RR 2.2 (1.2, 4.0) and those with a low social participation RR 1.6 (1.0, 2.7), low instrumental support RR 2.6 (1.2, 6.0), low support from the child's father RR 2.1 (1.0, 4.2) and those exposed to job strain RR = 2.3 (1.1, 4.8). The associations were independent of potential confounders such as age, educational level, nationality, cohabiting status, passive smoking, and previous years of smoking. CONCLUSIONS: This study supports the stress hypothesis. Smoking can be one way women handle stress when demands become too great. In order to reduce smoking among pregnant women, maternity centre resources need to be focused more on women with low psychosocial resources who are at highest risk for continued smoking. It is also important to involve actively the woman's partner or other important people in the woman's social network.