In the PIFSII, 870 women of the 1068 women eligible to participate were contacted and 587 completed baseline questionnaires (55%) and were maintained throughout the study period, representing 68% of women contacted. Those women discharged from hospital within the first 24 hours or not on the ward at the times that the researcher visited account for the eligible women not contacted. A similar proportion of eligible women participated in the PIFSI (58%) and the PIFSII (55%) studies. No significant differences were found in the age or level of education of participants compared with non-participants in either study [6,12].
A total of 226 women were smoking before pregnancy. This represents 39% of the total population of mothers. The proportion of mothers smoking decreased to 25% (n = 149) during pregnancy. Of the women who reported smoking before they became pregnant (n = 226), 34% of these (n = 77) stopped smoking during pregnancy, a reduction of 14%. Table 1 outlines the prevalence of smoking mothers and their partners.
Table 2 shows the results of the univariate analysis of smoking cessation during pregnancy using variables previously reported to be important and other relevant demographic variables. Stopping smoking during pregnancy was significantly associated with primiparous women (OR = 2.6; 95% CI 1.5–4.5; p
Table 3 shows the results of the multivariate analysis used to determine which variables were independent predictors of stopping smoking during pregnancy. It indicates that women who were primigravida and women who drank alcohol before pregnancy were more likely to stop smoking during pregnancy. Women who smoked more than ten cigarettes per day were less likely to stop smoking during pregnancy.
The association between stopping smoking and breastfeeding duration was explored using multivariate analysis. Table 4 indicates that stopping smoking during pregnancy was significantly related to breastfeeding duration. Of the 77 women who stopped smoking during pregnancy 35 (45%) of these continued to breastfeed for longer than six months. One hundred and forty nine women continued to smoke during pregnancy and of these, 34 (23%) breastfed for longer than six months. Women who stopped smoking were almost four times more likely to breastfeed for longer than six months, after adjustment for potential confounders (OR = 2.8; 95% CI 1.6 – 5.1; p