— A study by researchers at the University of Pittsburgh has
tied low vitamin D levels early in a woman’s pregnancy to an
increased risk of severe preeclampsia.
study was able to examine a database of 44,500 women, picking
out 717 that had developed preeclampsia. Severe preeclampsia
sometimes requires induced labor and delivery.
by the National Institutes of Health, the study will be
published next month in the journal Epidemiology.
women were part of the Collaborative Perinatal Project that
ran from 1959 to 1965, the nation’s largest-ever study of
pregnant women. The women’s blood was well preserved enough
to be tested for vitamin D levels.
looked at vitamin D levels prior to 26 weeks gestation and
examined whether there was any connection between low levels
and preeclampsia, a pregnancy disorder signified by high blood
pressure and elevated protein levels in urine. Complications
of untreated preeclampsia can be dangerous, even fatal, to a
woman and her baby.
the researchers did not find a connection between vitamin D
and mild preeclampsia, it did find a significant correlation
between vitamin D and severe preeclampsia.
D status of the mothers was not related to preeclampsia when
we looked at it overall, but when we separated it into two
different subtypes, that’s where we found a
relationship," said Lisa Bodnar, an associate professor
of epidemiology at Pitt’s Graduate School of Public Health
and lead author of the study.
study does not necessarily suggest, however, that women can
prevent preeclampsia by taking more vitamin D. It’s possible
that low vitamin D levels could be a side effect of the
preeclampsia, which may actually start long before it shows up
in a women’s blood pressure or urine protein levels.
also be that the relationship in the data set, collected in
the 1960s, no longer holds true today.
we found this relationship, but we don’t believe that women
should run out and start taking more vitamin D supplements
when they are planning a pregnancy or when they’re
pregnant," said Ms. Bodnar. "There’s still a lot
more research to be done."
severe preeclampsia is quite rare — occurring in roughly 5
out of 1,000 pregnancies — a very large sample would be
needed to examine further the vitamin D link.
would take a lot of resources and a lot of people to answer
the question right," said Bodnar.
such as this one are hard to do because the data set required
is so large, said Mark Caine, director of labor and delivery
at West Penn Hospital, calling the Pitt research "a study
that nobody else has really done."
that researchers have been looking for causes of preeclampsia
for some time, referring to a 10- to 15-year study on calcium
that ultimately couldn’t find a link to the disorder.
noted that vitamin D research is now in vogue, as researchers
aim to link it to numerous diseases, both in and out of
have been looking at vitamin D levels for several different
adverse pregnancy outcomes — intrauterine growth
restriction, preterm labor, diabetes," he said. "The
studies really still are all over the place."