Health In Focus
  • Vitamin C supplementation given to women who smoke during pregnancy reduces lung damage and improves lung function in their infants
  • Babies born to mothers who were given vitamin C supplementation during pregnancy have better lung function than those babies whose mothers were not given vitamin C
  • Nicotine found in cigarettes is highly addictive and smoking during pregnancy causes serious health effects in the baby including preterm birth, low birth weight, poor lung function and increased risk of birth defects

Vitamin C supplementation to pregnant women who smoke reduces the risk of lung damage in their infants, according to a recent randomized control study led by Dr. McEvoy, professor of pediatrics at Oregon Health & Science University. The findings of this study appear in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

Effects of Vitamin C on Baby's Lung Function

  • The study enlisted 251 volunteers who were randomly assigned to either receive vitamin C supplementation (125) or placebo (126) at 13 to 23 weeks of pregnancy
  • The team defined smoking as having smoked one or more cigarettes during the previous week. All the women were provided counseling and encouraged to quit smoking. During the study, 10% of the women kicked the smoking
  • Following delivery, lung function of their babies was evaluated by measuring the forced expiratory flow rate (FEF). FEF is a key parameter to measure lung function and estimates how quickly air can be exhaled from the lungs. It helps to determine the presence of airway obstruction
  • Infants whose mothers took 500 mg vitamin C supplement in addition to their regular supplements were found to have better FEF's compared to babies whose mothers received placebo
  • The study also found an association between FEF values and the occurrence of a genetic variant (α5 nicotinic acetylcholine receptor) which had a negative impact on lung function of babies resulting in lower FEF values. The presence of this genetic factor has been linked in previous studies to increased risk of development of lung cancer and obstructive lung disease
Thus, the findings of the study suggest that vitamin C plays a protective role in limiting lung injury of babies whose mothers smoke during pregnancy. The team also plans to continue follow-up of these infants to monitor their lung function and respiratory health.

In the words of Dr McEvoy, "Finding a way to help infants exposed to smoking and nicotine in utero recognizes the unique dangers posed by a highly advertised, addictive product and the lifetime effects on offspring who did not choose to be exposed."

Role of Vitamin C in Reducing Lung Damage

Vitamin C (ascorbic acid) is an antioxidant and helps prevent damaging of various tissues including the lungs. Oxidative stress causes injury and cell death due to the accumulation of free radicals such as peroxides within the cell.

Smoking reduces the levels of ascorbic acid resulting in decreased antioxidants to counter the oxidative stress by eliminating the free radicals.

Exposure of the fetus to smoke can thus cause lung damage and reduce lung function. Supplementing vitamin C to the mother restores antioxidant activity to counter the damage caused by free radicals and improve lung function.

Limitations of Previous Research

Previous research on the subject has shown that lung function measured on Day 3 of life was better in babies born to mothers who smoked and were given vitamin C (500 mg/day) supplementation during their pregnancy compared to babies of mothers who were randomized to placebo.

The earlier study employed passive methods to assess lung function of the babies whereas, the FEF employed in the current study is used in adults and older children to assess lung function and offers a more direct measurement of airway status.

Future Research Plans

Future plans include evaluating
  • Whether the benefits of starting vitamin C supplementation earlier would have greater benefit in improving the infant's lung function
  • The effect on lung function of supplementing the babies with vitamin C after birth
In conclusion, although vitamin C given to pregnant women who smoke helps lower the risk of lung damage in the baby, the primary aim should be to help the woman give up smoking since smoke exposure can cause obesity, behavioral disorders and other serious health issues later in these children.

Reference :

  1. Oral Vitamin C (500 mg/day) to Pregnant Smokers Improves Infant Airway Function at 3 Months (VCSIP): A Randomized Trial - (

Source: Medindia

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