Maternal smoking and newborn sex, birth weight and breastfeeding: a population-based study

Today, it is acknowledged that smoking during pregnancy and/or the postnatal period has significant risks for a foetus and newborn child. This research examines the relationship between smoking only postnatally, both during pregnancy and postnatally, and the newborn sex, birth weight and breastfeeding.

Total 664 women of randomly selected five primary healthcare centres between the dates 20 February 2010 and 20 July 2010 were included in the research. Statistical analyses were performed with SPSS for Windows 19.0 (Statistical Package for Social Sciences software package). Data were described as mean, standard deviation, percentages and Chi-square tests and backward stepwise logistic regression were analysed.

It was found that the percentage of smoking women with daughters is 2.5 times higher than women with sons. Women who smoke are 3.9 times more likely to start feeding their baby with supplementary infant foods at 4 months or earlier than those who do not smoke. Finally, the risk of a birth weight under 2500 g is 3.8 times higher for maternal smokers.

This study suggests that women who expect a girl smoke more heavily than those who expect a boy. The birth weight of maternal smokers' newborns is lower. Those women who smoke while breastfeeding start feeding their babies with supplementary infant foods at an earlier age.