Premature monochorionic monoamniotic twins have lower lung compliance at birth than matched dichorionic diamniotic twins.

BACKGROUND: Premature infants are born with immature lungs that demonstrate abnormal pulmonary function with differences in passive respiratory system compliance and resistance, and functional residual capacity. To our knowledge, no studies have evaluated differences in neonatal pulmonary function based on the type of twin gestation, or chorionicity. Given the effect of chorionicity on outcomes, we aimed to study the effect of twin type, monochorionic monoamniotic (MCMA) vs dichorionic diamniotic (DCDA), on neonatal early pulmonary function tests. METHODS: In this prospective cohort study, 5 sets of DCDA twins were matched to 5 sets of MCMA twins on gestational age at delivery, latency from antenatal corticosteroid exposure, birthweight, race and gender. Mean values were compared for passive respiratory system compliance and resistance, functional residual capacity, and tidal volume. RESULTS: MCMA infants had a significantly lower compliance (0.64 vs 1.25 mL/cm H2O /kg; p = 0.0001) and significantly higher resistance (0.130 vs 0.087 cm H2O /mL/sec; p = 0.0003) than DCDA infants. Functional residual capacity was lower for MCMA than DCDA infants (17.5 vs 23.4 mL/kg; p = 0.17). Further, 80% of MCMA infants required intubation for surfactant administration compared to 20% of DCDA infants, indicating the clinical significance of these objective measures. CONCLUSIONS: Due to the matched case-control design, causality cannot be established. However, we speculate that these differences in lung function may derive from differential exposure to preterm labor and endogenous maternal corticosteroid exposure. Further study is necessary to establish the true causal relationship.

Hair and nail nicotine levels of mothers and their infants as valid biomarkers of exposure to intrauterine tobacco smoke.

INTRODUCTION: Tobacco use remains the single most modifiable cause of adverse pregnancy outcomes. It is crucial to be able to accurately quantify the burden of tobacco exposure on both the mother and fetus to have better measures of efficacy with interventions being studied. METHODS: This is a descriptive and exploratory study conducted within a randomized controlled trial. Pregnant smoking and non-smoking women were followed from ≤22 weeks' gestation through delivery with monthly maternal smoking questionnaires, urine cotinine levels, and collection of maternal and infant hair and nail samples, at delivery. Nicotine was extracted and measured (ng/mg) using high-performance liquid chromatography with electrochemical detection. RESULTS: Forty-six mother-infant dyads (34 pregnant smokers and 12 pregnant non-smokers) had successful completion of maternal and infant hair and nails samples. The median hair nicotine levels of the smoking mothers and their infants was significantly higher than those of the non-smokers (1.015 vs 0.037 ng/ mg, p<0.05 for the mothers; 0.445 vs 0.080 ng/mg, p<0.01 for the infants). Similarly, the median nail nicotine levels for smoking mothers and their infants were significantly higher than the non-smokers (2.130 vs 0.056 ng/mg, p<0.01 for the mothers; 0.594 vs 0.132 ng/mg, p<0.05 for the infants). We found a moderate but significant correlation between maternal hair and nail nicotine (r=0.64, p<0.001), infant hair and nail nicotine (r=0.64; p<0.001), maternal and infant hair nicotine (r=0.61, p<0.001), and maternal and infant nail nicotine levels (r=0.58, p<0.001). CONCLUSIONS: Our study shows that both infant hair and nail nicotine levels are valid biomarkers of intrauterine tobacco smoke exposure, and can be used to identify prenatal smoke exposure, correlating well with the level of maternal nicotine exposure.

Pulmonary function in extremely low birth weight infants with bronchopulmonary dysplasia before hospital discharge.

OBJECTIVE: To compare pulmonary function in extremely low birth weight (ELBW) infants with bronchopulmonary dysplasia (BPD) studied at 34-36 weeks postmenstrual age (PMA) with a reference group of "healthy" infants born at 34-36 weeks. We hypothesized that ELBW infants have decreased functional residual capacity (FRC) and respiratory compliance (Crs). STUDY DESIGN: Pulmonary function testing was performed at 34-36 weeks PMA in infants with BPD and within 96 h of age in infants delivered at 34-36 weeks. RESULTS: Twenty BPD patients and 20 healthy infants were studied. FRC (18.9 versus 26.2 mL/kg; adjusted 95% CI 5.0, 10.9; P < 0.001) and Crs (0.80 versus 1.29-mL/cm H2O/kg; 95% CI 0.31, 0.71; P < 0.001) were decreased in BPD patients. Respiratory resistance was increased in BPD patients. CONCLUSIONS: ELBW infants with BPD have decreased pulmonary function compared to healthy infants delivered at 34-36 weeks. This suggests that infants with BPD have smaller lung volumes.

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.

Increased vitamin E intake is associated with higher alpha-tocopherol concentration in the maternal circulation but higher alpha-carboxyethyl hydroxychroman concentration in the fetal circulation.

BACKGROUND: The transfer of vitamin E across the placenta is limited, but no data exist on the concentrations of vitamin E metabolites carboxyethyl hydroxychromans (α- and γ-CEHCs) in the fetal circulation. OBJECTIVE: We measured α- and γ-CEHC concentrations in maternal and umbilical cord blood pairs and examined their relations to circulating vitamin E (α- and γ-tocopherol) and maternal dietary vitamin E intake. DESIGN: Healthy, pregnant women were enrolled from Oregon Health and Science University's obstetric clinic (<22 wk gestation), and at least one fasting blood sample and a previous day's 24-h diet recall were collected during their pregnancy (n = 19). Umbilical cord blood samples were obtained at the time of delivery and were analyzed for α- and γ-tocopherol, α- and γ-CEHC, and total lipid concentrations. RESULTS: Mean (±SD) concentrations of umbilical cord blood α-CEHC (30.2 ± 28.9 nmol/L) and γ-CEHC (104.5 ± 61.3 nmol/L) were not significantly different from maternal concentrations (P = 0.07 and 0.08, respectively), but metabolite:tocopherol ratios were significantly higher in cord blood (P < 0.01 and 0.001, respectively). Maternal α-tocopherol:total lipids ratios were correlated with cord blood α-CEHCs (r = 0.67, P = 0.004), and higher vitamin E intakes were associated with higher cord blood α-CEHC concentrations (r = 0.75, P < 0.003). CONCLUSION: Higher maternal intake of vitamin E during pregnancy may result in increased metabolite concentrations in the fetal circulation, suggesting increased maternal or fetal liver metabolism of vitamin E. This trial was registered at clinicaltrials.gov as NCT00632476.