Vitamins Not Shown to Reduce Preterm Births

There is statistical evidence that incidences of childbirth before the normal gestation period of 37 weeks of pregnancy–preterm births– have been on the rise in the U.S. since 1990. Various factors have been attributed to this phenomenon. This study was done to assess the success of medications containing the vitamins C and E in pregnant women in preventing preterm births. However, it was shown that extra vitamin C as well as E supplements given to mothers in early pregnancy did not reduce the frequency of preterm births.

Preterm births take place as a result of raised blood pressure, infections, and other causes, but occur most commonly due to the premature rupture of the amniotic membranes surrounding the baby. Vitamin C deficit has been known to be associated with “premature rupture of membranes”. This deficiency could be prevented by supplementation during pregnancy. Therefore, this study was conducted in order to assess the relationship between daily intake of vitamins C and E by pregnant women and its use in preventing the incidence of spontaneous premature rupturing of membranes. The researchers hypothesized that if vitamin C decreased chances of premature membrane rupturing, then “supplementation would be a correctional interventional behavior”.


  • This study was done at 16 clinics between 2003 and 2008. Approximately 10,000 first-time pregnant women were included in the study.
    • From early pregnancy (between nine weeks and sixteen weeks) until childbirth, the participants were given either a combination of vitamins C and E or placebos.
    • The incidences of premature birth owing to preterm rupturing of membranes were recorded. The gestational age at which the birth occurred was also noted.
    • The results were statistically analyzed.
  • Results

  • Spontaneous preterm birth occurred in 7.1 percent of the pregnant women who received daily vitamin C and E supplements, as against 6.9 percent in women who took placebos, indicating that supplementation with vitamin C and E did not reduce preterm births, i.e. births before 37 weeks.
  • No difference was seen between the two groups (supplements versus placebo), with regard to the age at which the premature birth occurred.
  • In the case of women who took supplements, there was a slight reduction in the incidence of premature births before 32 weeks of gestation. However, the authors suspect these may reflect an error in the study.
  • Shortcomings
    In this study, only women with rupture of membrane that occurred at least an hour before the onset of labor pains were considered to have premature rupturing of membrane.  The authors believe that there may have been incorrect categorizations.

    The total preterm childbirths in the United States in 2007 comprised 12.7 percent of all births. Vitamin C deficit has been proposed as a cause of premature membrane rupture. However, this study has shown that supplementations of vitamins C and E have been unsuccessful in preclusion of preterm birth. Supplementation of these vitamins also does not help change the condition of newborns that are born prematurely. The authors do not recommend further trials of this treatment in similar populations. They affirm that “Maternal supplementation with vitamins C  and E beginning at 9 to 16 weeks of gestation in nulliparous women at low risk did not reduce spontaneous preterm birth.”

    For More Information:
    Vitamin C & E Supplementation to Prevent Preterm Births
    Obstetrics and Gynecology, September 2010
    By John C. Hauth MD; Rebecca G. Clifton PhD
    From the University of Alabama at Birmingham, Birmingham, Alabama

    *FYI Living Lab Reports Are Summaries of the Original Research.
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