Pregnancy Complications Increase Women's Risk of Heart Disease, Death
DURHAM, N.C. -- Young women who have a range of
complications during pregnancy, including preeclampsia,
gestational diabetes or preterm birth, are at an increased risk
of developing heart disease and of dying later in life,
according to new analyses by a team of Duke University Medical
Center and Durham Veterans Affairs Medical Center cardiologists
and obstetricians. Preeclampsia is a condition characterized by
a sharp rise in blood pressure during pregnancy and may be
accompanied by edema (swelling) and kidney problems.
The researchers also found that mothers who continue to
smoke cigarettes during pregnancy are not only harming health
of the developing fetus but are doubling their own risks of
dying from future heart disease or from any cause.
These insights have important public health implications,
the researchers continued, because they identify young pregnant
women as a previously underappreciated group of patients who
would appear to benefit from targeted prevention efforts,
including smoking cessation efforts.
"Given the high percentage of women who continue to smoke
during their pregnancy, targeting this behavior would not only
benefit the health of the fetus but reduce the mother's future
risk for early death," said Duke cardiologist Mimi Biswas, M.D.
Biswas presented the results of two separate analyses March 13,
2006, during the 55th annual scientific sessions of the
American College of Cardiology in Atlanta.
Biswas's research is supported by the National Institutes of
Health's Building Interdisciplinary Research Careers in Women's
Health (BIRCWH) Fellowship and the ACC Foundation/Guidant
Foundation Fellowship and Career Development Award in Women's
"The complications during pregnancy that we studied could
have lasting effects on the cardiovascular system and can be
seen as novel early warning signs of future heart disease or
mortality risk," she continued. "Typically, younger women tend
not to be closely followed for cardiovascular disease – based
the results of our analyses, those with difficult pregnancies
"Knowing that these complications may have ramifications
later in life gives us a unique opportunity to catch women
early," Biswas said. "When women are young, they may tend to
focus on the care of their babies and gloss over going to the
doctor for their own care.
While population studies have associated complications
during pregnancy with adverse outcomes for the mother later in
life, few studies have sought to quantify the degree of risk,
the researchers said.
In their studies, the researchers used the Perinatal Health
Services Outcomes Database -- which includes all women who gave
birth at Duke between 1979 and 2005 -- and the Duke Information
System for Cardiovascular Care, which included all patients who
received a cardiac catheterization since 1969. They searched
the databases for patients who appeared on both, and separated
them into two groups – one that had complications during
pregnancy and one that did not.
For their analyses, pregnancy complications included
preeclampsia, gestational diabetes or preterm birth, in utero
fetal death, small- and large-for gestational age, post-partum
hemorrhage, stillbirth and twins.
In their study, the Duke team performed two analyses – one
that looked for association between pregnancy complications and
the development of cardiovascular disease seen on cardiac
catheterization, while the other looked for association with
mortality, both cardiac and from all causes.
In the coronary artery disease analysis, 210 out of 404
patients who appeared on both databases had pregnancy
complications; while 183 out of 339 patients in the mortality
analysis had complications. In general, the women with
pregnancy complications had higher rates of diabetes,
hypertension, smoking during pregnancy and confirmed coronary
artery disease on catheterization.
"However, after statistically adjusting for those medical
risks factors, we still found that pregnancy complications
added an independent 1.6-fold risk for the development of
cardiovascular disease," Biswas said. "Again, after adjusting
for those medical factors, we also found that pregnancy
complication was an independent risk factor for all-cause
death, increasing that risk over two-fold."
The researchers also found that after adjusting for the
other clinical variables, smoking more than doubled the risk of
all-cause death, almost tripled the risk of cardiac death, and
almost doubled the risk of developing coronary artery
For the coronary artery disease analysis, the average age of
delivery was 28 years and 42 was the average age at
catheterization. In the mortality analysis, average age of
delivery was 27 and 41 years for catheterization.
"We know that in general, when women come to the hospital
with a heart attack, they tend to be older and have diabetes
and hypertension, and they tend to have worse outcomes," she
continued. "But if we could identify them early in life, we
could take the appropriate preventative measures and forestall
the bad outcomes. Pregnancy history can be a red flag to
identify women at increased future risk."
Since the women with the worse outcomes tend to be younger,
the Duke team plans further studies looking for genetic factors
that may be involved. As older women come to the
catheterization labs for treatment, the team is also collecting
past obstetric information as well.
Other members of the Duke team included Monique Chireau,
M.D., Emily Honeycutt MBI, Haywood Brown, M.D., Kristin Newby,
M.D., and Lori Bastian, M.D.