Women who smoke during their pregnancy place their unborn child at an increased risk of
health problems, including decreased lung function and possible lung diseases later in life.
Preliminary animal research suggests that if vitamin C is taken during pregnancy, nicotine's
harmful effects on the unborn baby's developing lungs may be blocked. This study will
determine the effect that vitamin C has on the lung development and function of babies born
to women who smoke during pregnancy.
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.
- Randomly assigned to a study intervention at less than 22 weeks of gestation
- History of smoking
- Singleton gestation pregnancy
- Smoking cessation intervention offered but declined
- Multiple gestation pregnancy
- Documented major fetal congenital anomalies
- History of kidney stones
- Insulin dependent diabetes
- Current participation in other research projects that may interfere with this study
- Continuous use of high dose vitamin C since last menstrual period (LMP) or initial
ascorbic acid level greater than 100 micromoles/liter