Women who take multivitamins while pregnant lower their risk of having an
underweight baby.
So concludes a major new study by Canadian researchers that challenges the World
Health Organization strategy of recommending iron and folic acid supplements
alone.
Low birth weight is a leading cause of illness and death in newborns, and a
condition that has lasting effects throughout life.
Newborns weighing less than 2,500 grams — about 5 1/2 lbs. — are considered to
be underweight, and such births are becoming more common in Canada.
In 2008, a total of 367,089 babies were born in Canada. About six per cent were
low birth-weight babies. That's up from 5.7 per cent of hospital births in
2001-02. No one knows why the rate is increasing, but one theory attributes it
to a greater frequency of multiple births, such as twins and triplets, from
reproductive technologies. The rate also goes up significantly for women 35 and
older.
The rate also goes up significantly for women aged 35 and older.
Babies born weighing less than normal are at a higher risk of being admitted to
the intensive care unit. They also have an increased risk of infections, feeding
problems, cerebral palsy, poor growth and mortality. Low birth weight is the
leading cause of death in the first year of life.
And the risks continue as the child grows: Several studies have linked low birth
weight to problems with thinking, learning and memory in childhood, as well as
to a higher risk of heart disease, diabetes, depression and other chronic
illnesses in adulthood.
Low birth weight and the complications that go with it "are considered the most
common cause of mortality globally among infants under the age of five,"
researchers from Toronto's Mount Sinai Hospital and the University of Toronto
report in a study to be published Tuesday in the Canadian Medical Association
Journal.
The World Health Organization currently recommends, based on a review it did in
2005, that all pregnant women take iron and folic acid supplements to improve
fetal growth and to prevent spina bifida and neural tube defects.
When WHO compared studies available at that time, it concluded multivitamins
didn't add any extra benefit over folic acid and iron alone, the Canadian
researchers say. But since then, several randomized, controlled trials have been
done.
The Toronto team pooled the results of 13 studies, including more recent ones,
and found that, compared to placebos, or sugar pills, "multivitamins were
effective in reducing low birth weight," says lead author Dr. Prakesh Shah, a
neonatologist at Mount Sinai and associate professor at the University of
Toronto.
Compared with iron and folic acid alone, multivitamins lowered the risk of low
birth weight by 17 per cent.
"It's a very significant effect," Shah said.
Multivitamins are thought to boost immune function in women, improve their
overall nutritional status and improve fetal growth.
Overall, the birth weight of babies was 54 grams higher, on average, among
babies born to women given multivitamins than among those who received
iron-folic acid supplements alone.
It's estimated that of the total of 133 million births worldwide every year,
15.5 per cent, or about 20 million, are low birth-weight babies. Shah's team
estimates that if all women were given multivitamin supplements, there would be
1.5 million fewer low birth-weight babies born every year.
"The current strategy recommended by the World Health Organization of providing
only iron-folic acid supplementation to pregnant women needs to be challenged in
light of the evidence from our review," Shah and his colleagues say.
The Society of Obstetricians and Gynaecologists of Canada recommends pregnant
women take folic acid in combination with a multivitamin supplement, but
primarily for the prevention of neural tube defects and other congenital
anomalies.
Shah says different studies used different vitamin combinations, but the
components that came out consistently in his team's review included:
Vitamin A (2,640 IU, or international units), vitamin D (200 IU), vitamin E (10
milligrams), vitamin B1 (1.4 milligrams), folic acid (400 micrograms), vitamin C
(70 milligrams), zinc (15 milligrams) and iron (30 milligrams). Shah says women
should start taking multivitamins as soon as they know they are pregnant and
continue taking them throughout their pregnancy.
But Dr. Vyta Senikas says women should start taking supplements as soon as they
are thinking of conceiving.
"The fact that birth weight can positively benefit is certainly welcome news,"
said Senikas, the society's associate executive vice-president.
"In today's climate, women are always looking for ways to give their child the
best start in life possible," she said. "I think the most important next step
here is (the study) gives women the impetus to consider starting supplementation
with these vitamins and folic acid before they conceive."
Source : Canwest News Service
