Calcium Supplements Help Babies' Bones in Calcium Deficient Women
Nov. 29, 1999 (Atlanta) -- For pregnant women receiving low amounts of
calcium in their diet, taking calcium supplements averaging 1,300 mg a day
during the second and third trimesters of pregnancy can increase the bone
mineral content of their fetus by about 15%. However, according to a study in
the October issue of the journal Obstetrics & Gynecology, for women
who receive adequate calcium in their diets, calcium supplements are unlikely
to result in much improvement in fetal bone mineralization. Babies born with
better mineralization have stronger bones and a boost to their development.
This new study, done at the University of Tennessee in Memphis, involved 256
women in their fourth month of pregnancy. Half the women were given up to two
grams of supplemental calcium carbonate per day while the others were given a
placebo. The women were checked for the effects of the supplementation up until
they gave birth. One week after birth, the infants underwent x-ray studies of
their whole bodies to check for bone mineral content.
The results found that for mothers with the lowest rate of calcium intake
(less than 600 mg per day), the total skeletal bone mineral content was
significantly higher in infants of calcium-supplemented mothers compared to the
calcium-deficient placebo group. The babies from mothers with adequate calcium
in their diet, who were given supplements, had about the same mineral content
as the mothers in their corresponding placebo group.
According to the lead author, Winston W. K. Koo, MD, now at Wayne State
University/Hutzel Hospital in Michigan, supplementation's minimal effect on
fetal bone mineralization in women with adequate dietary calcium intake may be
due to a "maternal homeostatic response." In other words, the mother's
body may protect the fetus by decreasing the absorption and retention of
calcium at very high rates.
The results of the study do not mean women shouldn't take the supplements.
Pregnant women do have additional calcium needs and the supplements provide for
those needs. Rather, this new research shows that if the mother's diet provides
adequate amounts of calcium and she also takes supplements, there is
little or no effect on the fetus.
Koo notes that low maternal calcium intake appears to critically affect
fetal bone mineralization, and warns that calcium-poor diets can occur even in
societies where food is plentiful. Other research shows that calcium
deficiencies can also lead to preeclampsia, a condition during pregnancy
characterized by high blood pressure, swelling, and weight gain greater than
one pound per day. Studies show the risk of preeclampsia is between 45% and 74%
lower for women who received calcium supplementation.
Koo says the best way to assure normal fetal bone mineralization is for the
mother to eat sufficient amounts of calcium-rich foods. "Calcium-rich foods
are also rich in other nutrients critical to bone health [such as vitamin
D]," says Koo.