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 daily vitamin C would have improved pulmonary function tests (PFTs) and decreased wheezing compared to those randomized to placebo. Design, Setting, Participants, Intervention Randomized, double-blind trial in three sites in the Pacific Northwest. Between March 2007 and January 2011, 206 pregnant smokers were recruited and 179 randomized to vitamin C (500 mg/day) versus placebo (89 to vitamin C and 90 to placebo). 159 newborns of randomized pregnant smokers (76 vitamin C treated and 83 placebo treated) and 76 of pregnant nonsmokers were studied with newborn PFTs. Follow-up assessment including wheezing was assessed through one year of age and PFTs were done at one year of age. Main Outcomes and Measures The primary outcome was measurements of newborn pulmonary function (specifically the 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 one year of age and PFTs at one year of age. A subgroup of pregnant smokers and nonsmokers had genotyping performed. Results Newborns of women randomized to vitamin C (n= 76) had improved pulmonary function as measured by TPTEF:TE (0.383 vs 0.345; adjusted 95% confidence interval [CI] for difference 0.011, 0.062; p =0.006) and Crs/kg (1.32 vs 1.20 mL/cm H2O/kg; 95% CI 0.02, 0.20; p =0.012) than those randomized to placebo (n=83). Offspring of women randomized to vitamin C had significantly decreased wheezing through 1 year of age (15/70 [21%] vs 31/77 [40%]; relative risk 0.56, 95% CI 0.33, 0.95; p =0.03). There were no significant differences in the one year PFTs between the vitamin C and placebo groups. The effect of maternal smoking on newborn lung function was associated with maternal genotype for the alpha 5 nicotinic receptor (rs16969968) (p value for interaction = 0.0006). Conclusion and Relevance Supplemental vitamin C to pregnant smokers improved newborn PFTs 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

Objective-To compare respiratory compliance (Crs) and functional residual capacity (FRC) in infants randomized to a rescue course of antenatal steroids (AS) versus placebo.Study Design-Randomized, double-blinded trial. Pregnant women ≥ 14 days after initial AS were randomized to rescue AS or placebo. The primary outcomes were measurements of Crs and FRC. This study is registered with clinicaltrials.gov [NCT00669383].Results-44 mothers (56 babies) received rescue AS and 41 mothers (57 babies) received placebo. There was no significant difference in birth weight, or head circumference. Infants in the rescue group had an increased Crs (1.21 versus 1.01 mL/cm H 2 O/kg; adjusted 95% CI 0.01, 0.49; p =0.0433) compared to placebo. 13% in the rescue versus 29% in the placebo group required ≥ 30% oxygen (p <0.05). Patients delivered at ≤ 34 weeks had greater pulmonary benefits.Conclusion-Infants randomized to rescue AS have a significantly increased Crs compared to placebo.

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