Vitamin C may benefit lung health of infants from pregnant smokers

A new US study says that increased intakes of vitamin C by women who smoke during pregnancy seem to improve measures of lung function for their newborns and decrease the incidence of wheezing for their infants through one year.

In the randomized controlled trial, the lung function of 159 newborns of women who smoked during preg- nancy and 76 newborns of women who did not smoke was measured (1). The pregnant smokers and non-smokers received either 500 mg vitamin C daily or a placebo during pregnancy. The study results showed that newborns of women who took vitamin C supplements, compared with those of the placebo group, had improved measures of pulmonary function. In addition, offspring of women in the vitamin C group had significantly decreased wheezing through age one year.

The researchers commented that vitamin C supplementation in pregnant smokers may be a simple approach to decrease some of the effects of smoking in pregnancy on newborn pulmonary function and ultimately infant respiratory morbidities. However, achieving smoking cessation should be the primary goal for women who smoke and who intend to or become pregnant. By not smoking during pregnancy and preventing her newborn infant from becoming exposed to tobacco smoke, a woman can do more for the respiratory health and overall health of her developing fetus or child than any amount of vitamin C may be able to achieve.

More than 50% of smokers who become pregnant continue to smoke, corresponding to 12% of all pregnan- cies (2). Smoking during pregnancy adversely affects lung development, with lifelong decreases in lung function (3). At birth, newborn infants born to smokers show decreased pulmonary function test (PFT) re- sults, with respiratory changes leading to increased hospitalization for respiratory infections and increased incidence of childhood asthma.

1. McEvoy C. T. Vitamin C Supplementation for Pregnant Smoking Women and Pulmonary Function in Their Newborn Infants: A Randomized Clinical Trial. JAMA. Published online May 2014.
   
2. Filion K. B. et al. The effect of smoking cessation counselling in pregnant women: a meta-analysis of randomised controlled trials. BJOG. 2011; 118(12):1422–1428.
   
3. Hayatbakhsh M. R. et al. Maternal smoking during and after pregnancy and lung function in early adulthood: a prospective study. Thorax. 2009; 64(9):810–814.