A recent study found that vitamin C supplementation in pregnant smokers significantly improved airway function and reduced wheezing in children as young as 5 years old.
Prenatal exposure to smoke from maternal smoking increases the risk of impaired lung development, decreases airway function, and increases the risk of wheezing and asthma. More than 10% of individuals in the United States smoke during pregnancy, and more than 400,000 infants are exposed to smoke in utero.
Lower airway function in childhood often leads to similar deterioration in adulthood, increasing the risk of respiratory disease and chronic obstructive pulmonary disease. Randomized controlled trials have shown that children’s airways improve when mothers receive vitamin C supplementation during pregnancy, but the results of these trials have been mixed.
To determine whether improved airway function can be achieved early in life and maintained until preschool age, researchers investigated the use of vitamin C to reduce the effects of smoking during pregnancy on infant lung function. A follow-up study was performed to examine forced expiratory flow (FEF) in a 5-year-old patient.
Participants in this trial included pregnant women aged 15 years and older with one confirmed pregnancy between 13 and 22 weeks. These individuals also spoke English, and at least one of her had smoked and had been treated at a clinic near the recruitment site in the past week.
Participants were randomly assigned to two groups. Data on participants’ smoking history and medical adherence were collected, and participants received brief smoking cessation counseling.
At follow-up, FEF measurements were collected for the 5-year-old child. FEFs are 25% to 75% expiratory volume (FEF25-75), FEF at 50% expiratory volume (FEF50), and FEF at 75% expiratory volume (FEF75). ) are all recorded. Parents and caregivers were also surveyed for the prevalence of wheezing in children from her 4th year to her 6th birthday.
213 children were evaluated, with a mean age of 3.1 years in the vitamin C group and 3.2 years in the placebo group. Her successful FEF measurement at age 5 was recorded in her 90.1% of these children.
FEF25-75 measures were significantly improved in children born to pregnant smokers with vitamin C supplementation compared to placebo, with a mean difference of 17.2%. Mean FEF50 and FEF75 measurements were also significantly improved in children born to women in the vitamin C supplementation group.
The incidence of wheezing was also significantly lower in children born to pregnant smokers treated with vitamin C supplements compared to placebo. It was associated with improved airway function in children born to smokers.
McEvoy CT, Shorey-Kendrick LE, Milner K, Harris J, Vuylsteke B, Cunningham M, et al. Effects of vitamin C supplementation in pregnant smokers on airway function and wheezing in 5-year-olds: follow-up of a randomized clinical trial. . JAMA Pediatrics2023;177(1):16–24. doi:10.1001/jamapediatrics.2022.4401