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Evaluating the Effects of Supplemental Vitamin C on Infant Lung Function in Pregnant Smoking Women

This study has been completed.
National Heart, Lung, and Blood Institute (NHLBI)
National Institute of Environmental Health Sciences (NIEHS)
Information provided by (Responsible Party):
Cynthia McEvoy, National Heart, Lung, and Blood Institute (NHLBI) Identifier:
First received: March 5, 2008
Last updated: August 31, 2013
Last verified: August 2013
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.

Condition Intervention
Other: Placebo
Dietary Supplement: Vitamin C

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: In-Utero Smoke, Vitamin C, and Newborn Lung Function

Resource links provided by NLM:

Further study details as provided by Oregon Health and Science University:

Primary Outcome Measures:
  • 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 ]

Secondary Outcome Measures:
  • 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 ]

Enrollment: 282
Study Start Date: March 2007
Study Completion Date: July 2012
Primary Completion Date: July 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Placebo Comparator: A
Participants will receive a placebo capsule throughout pregnancy.
Other: Placebo
Placebo capsule once a day
Other Name: Sugar pill
Active Comparator: B
Participants will receive a vitamin C capsule throughout pregnancy.
Dietary Supplement: Vitamin C
A 500-mg vitamin C capsule once a day
Other Name: Ascorbic acid
No Intervention: C
A group of non-smoking pregnant women will not receive placebo or vitamin C.

Detailed Description:

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.


Ages Eligible for Study:   15 Years and older   (Child, Adult, Senior)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • 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

Exclusion Criteria:

  • 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
  Contacts and Locations
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Please refer to this study by its identifier: NCT00632476

United States, Oregon
Oregon Health & Science University
Portland, Oregon, United States, 97266
Sponsors and Collaborators
Oregon Health and Science University
National Heart, Lung, and Blood Institute (NHLBI)
National Institute of Environmental Health Sciences (NIEHS)
Principal Investigator: Cynthia T. McEvoy, MD Oregon Health and Science University
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Cynthia McEvoy, Associate Professor of Pediatrics, National Heart, Lung, and Blood Institute (NHLBI) Identifier: NCT00632476     History of Changes
Other Study ID Numbers: 546
K23HL080231 ( US NIH Grant/Contract Award Number )
K23HL080231-01A1 ( US NIH Grant/Contract Award Number )
Study First Received: March 5, 2008
Last Updated: August 31, 2013

Keywords provided by Oregon Health and Science University:
Smoking During Pregnancy
Vitamin C
Newborn Lung Function
Ascorbic Acid

Additional relevant MeSH terms:
Ascorbic Acid
Growth Substances
Physiological Effects of Drugs
Molecular Mechanisms of Pharmacological Action
Protective Agents processed this record on May 22, 2017