Patricia Spitale

Vitamin C Supplementation for Pregnant Smoking Women and Pulmonary Function in Their Newborn Infants: A Randomized Clinical Trial

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.

Respiratory compliance in preterm infants after a single rescue course of antenatal steroids: a randomized controlled trial

OBJECTIVE To compare respiratory compliance and functional residual capacity in infants randomized to a rescue course of antenatal steroids vs placebo. STUDY DESIGN Randomized, double-blinded trial. Pregnant women > or =14 days after initial antenatal steroids were randomized to rescue antenatal steroids or placebo. The primary outcomes were measurements of respiratory compliance and functional residual capacity. This study is registered with clinicaltrials.gov (NCT00669383). RESULTS Forty-four mothers (56 infants) received rescue antenatal steroids and 41 mothers (57 infants) received placebo. There was no significant difference in birthweight, or head circumference. Infants in the rescue group had an increased respiratory compliance (1.21 vs 1.01 mL/cm H(2)O/kg; adjusted 95% confidence interval, 0.01-0.49; P = .0433) compared with placebo. 13% in the rescue vs 29% in the placebo group required > or =30% oxygen (P < .05). Patients delivered at < or =34 weeks had greater pulmonary benefits. CONCLUSION Infants randomized to rescue antenatal steroids have a significantly increased respiratory compliance compared with placebo.

Pulmonary function and outcomes in infants randomized to a rescue course of antenatal steroids

Our objective was to obtain follow‐up pulmonary function testing and assessment of clinical respiratory outcomes, at 1‐2 years, in preterm infants whose mothers were randomized to a single rescue course of antenatal steroids (AS) versus placebo.