This study examined health behaviours among nulliparous pregnant Swedish wo
men. Structural equation modelling (N = 350) was used to predict smoking an
d exercise at gestational weeks 20 and 32 from psychosocial factors measure
d in early and mid-pregnancy. Although women altered their lifestyle early
in pregnancy, so that by gestational week 20 both smoking and exercise had
declined, previous behaviours remained strong and consistent predictors of
later behaviours. Hostility and health awareness predicted smoking at both
weeks 20 and 32. Smoking at week 32 was also predicted by concurrent percei
ved stress. Exercise at week 20 was predicted by hostility, social support,
stress, and whether or not the pregnancy was planned; and at week 32 only
health awareness was significant. Social support had a significant indirect
effect on each behaviour, which suggests that social support facilitated c
ompliance with health professionals' recommendations. These results suggest
that psychosocial factors previously associated with health outcomes also
predict health behaviours throughout pregnancy.