Vitamin C Eased the Wheeze of Pregnant Smokers' Babies

Vitamin C supplements during pregnancy improved breathing and lung capacity of babies

(RxWiki News) What's good for moms-to-be tends to be good for their unborn children. What's not good for mom, like smoking tobacco, also tends not to be good for babies. There may be an easy way to undo some of the damage.

In a recent study, infants born to smoking mothers who were given vitamin C while pregnant had better breathing functions than infants whose mothers were not given such treatment.

This finding should not encourage women to continue smoking through pregnancy. As noted in an editorial accompanying this study, quitting smoking early in pregnancy can reduce the effects that smoking has on an infant's breathing function.

"Ask your doctor for help to stop smoking."

This study’s lead author was Cindy McEvoy, MD, MCR, of the Oregon Health & Science University’s pediatrics department.

For this clinical trial, Dr. McEvoy and colleagues prescribed 500 milligrams of vitamin C daily to 76 pregnant smokers. Placebos, or pills containing no vitamin C, were given to another 83 pregnant smokers.

From within 72 hours of their babies’ birth up through their first birthday, the researchers measured the overall lung capacity of those babies, including how much they wheezed while breathing. They were measured during sleep, when they were being held upright, and while wearing a breathing mask.

After one year, 40 percent of the babies whose mothers took vitamin C while pregnant were wheezing less than they did at birth. By comparison, 21 percent of babies whose mothers were given the placebo wheezed less than when they were newborn, the researchers found.

In other words, babies born to smokers who took vitamin C were 56 percent less likely to wheeze by the time they were 1 year old. The vitamin C babies also required less medicine for wheezing.

“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 [ability],” these researchers wrote.

In an opinion piece accompanying the study, Graham Hall, PhD, of the University of Western Australia in West Perth, Australia, wrote that "smoking cessation — especially for woman planning to have children — remains one of the most important public health efforts to improve maternal and fetal health."

Dr. Hall added that although this study involved a relatively small number of patients, "the improvement in lung functions reported here could lead to future benefits."

Overall, both groups of babies had better pulmonary function at the end of that year, and there was no significant difference in that improvement made by both groups of babies.

The study involved women treated at three sites in the Pacific Northwest from March 2007 through January 2011. The females were at least 15 years old and resided in Portland, OR or Vancouver, WA.

The researchers wrote that more than half of smokers who get pregnant continue smoking during their pregnancies. That group of pregnant smokers accounts for 12 percent of all pregnancies.

For this study, 41 percent of the women taking vitamin C and 36 percent of women taking the placebo smoked 10 or more cigarettes a day.

The resulting pulmonary and respiratory damage done to babies whose mothers smoke during pregnancy can have long-term effects. Such children are at heightened risks for breathing-related illnesses and hospitalizations, including for asthma. In asthma, the lungs’ airways become too narrow, causing coughing, wheezing, chest tightness and breathing difficulties. At its most severe, asthma can be fatal.

This study was published online May 27 in JAMA.

The National Heart, Lung and Blood Institute funded the study.

One of the study's 16 researchers reported receiving grants from and owning stock in Pfizer.

Review Date: 
May 27, 2014