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JAMA. 2014 May;311(20):2074-82. doi: 10.1001/jama.2014.5217.

Vitamin C supplementation for pregnant smoking women and pulmonary function in their newborn infants: a randomized clinical trial.

Author information

  • 1Oregon Health & Science University, Portland.
  • 2PeaceHealth Southwest Medical Center, Vancouver, Washington.
  • 3Vancouver Clinic, Vancouver, Washington.
  • 4Providence Maternal Care Clinic, Portland, Oregon.
  • 5Oregon National Primate Research Center, Beaverton.
  • 6University of Southern California, Keck School of Medicine, LAC-USC Medical Center, Los Angeles, California.
  • 7Linus Pauling Institute, Oregon State University, Corvallis.

Abstract

IMPORTANCE:

Maternal smoking during pregnancy adversely affects offspring lung development, with lifelong decreases in pulmonary function and increased asthma risk. In a primate model, vitamin C blocked some of the in-utero effects of nicotine on lung development and offspring pulmonary function.

OBJECTIVE:

To determine if newborns of pregnant smokers randomized to receive daily vitamin C would have improved results of pulmonary function tests (PFTs) and decreased wheezing compared with those randomized to placebo.

DESIGN, SETTING, AND PARTICIPANTS:

Randomized, double-blind trial conducted in 3 sites in the Pacific Northwest between March 2007 and January 2011. One hundred fifty-nine newborns of randomized pregnant smokers (76 vitamin C treated and 83 placebo treated) and 76 newborns of pregnant nonsmokers were studied with newborn PFTs. Follow-up assessment including wheezing was assessed through age 1 year, and PFTs were performed at age 1 year.

INTERVENTIONS:

Pregnant women were randomized to receive vitamin C (500 mg/d) (n = 89) or placebo (n = 90).

MAIN OUTCOMES AND MEASURES:

The primary outcome was measurement of newborn pulmonary function (ratio of the time to peak tidal expiratory flow to expiratory time [TPTEF:TE] and passive respiratory compliance per kilogram [Crs/kg]) within 72 hours of age. Secondary outcomes included incidence of wheezing through age 1 year and PFT results at age 1 year. A subgroup of pregnant smokers and nonsmokers had genotyping performed.

RESULTS:

Newborns of women randomized to vitamin C (n = 76), compared with those randomized to placebo (n = 83), had improved pulmonary function as measured by TPTEF:TE (0.383 vs 0.345 [adjusted 95% CI for difference, 0.011-0.062]; P = .006) and Crs/kg (1.32 vs 1.20 mL/cm H2O/kg [95% CI, 0.02-0.20]; P = .01). Offspring of women randomized to vitamin C had significantly decreased wheezing through age 1 year (15/70 [21%] vs 31/77 [40%]; relative risk, 0.56 [95% CI, 0.33-0.95]; P = .03). There were no significant differences in the 1-year PFT results between the vitamin C and placebo groups. The effect of maternal smoking on newborn lung function was associated with maternal genotype for the α5 nicotinic receptor (rs16969968) (P < .001 for interaction).

CONCLUSIONS AND RELEVANCE:

Supplemental vitamin C taken by pregnant smokers improved newborn PFT results and decreased wheezing through 1 year in the offspring. Vitamin C in pregnant smokers may be an inexpensive and simple approach to decrease the effects of smoking in pregnancy on newborn pulmonary function and respiratory morbidities.

TRIAL REGISTRATION:

clinicaltrials.gov Identifier: NCT00632476.

PMID:
24838476
[PubMed - indexed for MEDLINE]
PMCID:
PMC4296045
Free PMC Article
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