• Pulmonary function testing (including respiratory compliance and the ratio of time to peak tidal expiratory flow to total expiratory time) [ Time Frame: Measured within 48 hours after delivery ] [ Designated as safety issue: No ]
  

• Pulmonary function testing (including respiratory compliance and the ratio of time to peak tidal expiratory flow to total expiratory time)and respiratory history including wheezing through 12 months of age. [ Time Frame: Measured at 12 months of age ] [ Designated as safety issue: No ]
  

Approximately 12% of women smoke during pregnancy, and at least 500,000 babies are born each year having been exposed to nicotine. These infants have poor lung function at birth and have an increased risk of developing lung diseases, including bronchitis, pneumonia, and asthma. Researchers believe that nicotine may interact with nicotinic receptors in the unborn child's developing lungs and cause altered growth and decreased lung function. Preliminary animal research studies suggest that some of the harmful effects of nicotine may be blocked by vitamin C, an antioxidant that may protect against cellular damage caused by nicotine and other pollutants. The purpose of this study is to evaluate the effectiveness of vitamin C at blocking the harmful effects of nicotine exposure on lung development and function in children born to women who smoke during pregnancy.

This study will enroll pregnant women who smoke, as well as a control group of pregnant women who do not smoke. At a baseline study visit, all participants will complete smoking history questionnaires. For 2 weeks, all participants who smoke will receive placebo capsules once a day. They will then be randomly assigned to receive either vitamin C capsules or placebo capsules, both of which will be taken once a day, in addition to a prenatal vitamin, for the duration of their pregnancy. Study visits, occurring once a month throughout the pregnancy, will include a medical and smoking history review and urine collection. An ultrasound exam will be performed once during the pregnancy to determine the exact size and age of the baby, and blood collection will occur at baseline and once or twice more during the pregnancy. Study researchers will review participants' medical records and will call participants three times during their pregnancy to review their food intake. At the time of delivery, amniotic fluid samples will be collected. When babies are 48 hours old, baby lung function testing will occur, and when babies are 3 and 9 months of age, researchers will call participants to collect breathing information on the babies. When babies are 12 months old, participants will attend a study visit that will include urine collection from the babies and a review of baby breathing difficulties, medication changes, and environmental smoking exposure.