A disappointing new study found that vitamin C
and E supplements given to healthy pregnant women
do not reduce their risk of developing preeclampsia,
a complication that can be lethal to both mother
and child.
Similarly, a recent British study found that the
supplements do not help women who run a high risk
of preeclampsia, and might even harm their babies
by leading to low birth weight.
Preeclampsia happens when vessels in the mother's
womb constrict, cutting off blood and oxygen to
the fetus. It occurs in late pregnancy and produces
a spike in blood pressure. No one knows why it happens,
and there is no effective treatment other than inducing
early delivery.
The condition kills about 76,000 women and babies
a year worldwide. In the United States, it occurs
in about 8 percent of pregnancies and accounts for
15 percent of premature births.
Pregnant women routinely take a prenatal multivitamin
containing small amounts of vitamins C and E, and
a previous small study suggested that supplements
might help prevent preeclampsia.
However, in light of the new research, some doctors
are saying expectant mothers should not take supplements
beyond what is in their multivitamin.
"Given the information that we have, I would not
recommend taking additional vitamins C and E," said
Dr. Arun Jeyabalan, an obstetrician at the University
of Pittsburgh School of Medicine who had no role
in the research.
The study, led by researchers from the University
of Adelaide in Australia, was published in the
New England Journal of Medicine.
In the study, 1,877 healthy women took either vitamins
or dummy pills during their second trimester. The
women were not allowed to take other over-the-counter
supplements, but a prenatal multivitamin was allowed.
The supplement group took four pills a day totaling
1,000 milligrams of vitamin C and 400 international
units of vitamin E until they gave birth. A prenatal
multivitamin contains about 70 milligrams of vitamin
C and 15 IUs of vitamin E.
About 6 percent of moms in each group developed
preeclampsia, and 10 percent of babies in each group
had serious complications, including death.
Women who took supplements had higher rates of
blood pressure and hospitalization. But the results
were not statistically significant, and researchers
said the difference could have occurred by chance.
Health experts say the study leaves open the question
of whether expectant mothers in Third World countries
with inadequate diets might benefit from high-dose
supplements. Several international studies are under
way to help answer that question.
A large government-funded study involving about
10,000 healthy women is also under way in the United
States.
In recent years, doctors have warned that vitamins
can have harmful effects, especially at higher doses.
Vitamins and other supplements, which are available
at supermarkets and are relatively inexpensive,
are loosely regulated and their health claims are
unproven.
Large doses of vitamin E earlier were found to
be ineffective against heart attacks and cancer.
