Black Moms Face Triple the Risk of 'Preemie' Birth
Black women are three times more likely than white women to deliver their
babies prematurely, a new study reveals. Even worse, they are four times more
likely to give birth extremely prematurely — between 20 to 28 weeks
Genetics are the most likely reason for the phenomenon, the study’s lead
“It has been known that African-American women have an increased risk of
preterm delivery,” said Dr. Louis J. Muglia, director of the Center for Preterm
Birth Research at Washington University School of Medicine, in St. Louis. “By
this study we are trying to understand the foundation for that effect.”
His team published its findings in the February issue of the American
Journal of Obstetrics and Gynecology.
The study tracked more than 700,000 births in Missouri from 1989 to 1997.
The researchers found that black women were three times more likely than
their white counterparts to give birth at 20 to 34 weeks of pregnancy, rather
than full-term (from 37 to 41 weeks).
The researchers controlled for socioeconomic factors, such as maternal age
and economic status, Muglia said. Without adjusting for those factors, “the
incidence of premature delivery would be 6.5-fold higher than in Caucasians,” he
In addition, 21.5 percent of the black women in the study had more than one
premature delivery, compared to 9.2 percent of white women, the study found.
While there is no direct proof that genetic differences drive the disparity,
the evidence does point in that direction, Muglia said. His group now is engaged
in studies to try to prove that notion, he added.
“What we would like to do is identify in a broad way the factors that
increase the incidence of premature delivery,” Muglia said. “We want to identify
families and examine them for polymorphisms,” genetic differences associated
with an increased incidence of premature childbirth.
Muglia and his colleagues have been working with 75 families in the St. Louis
area for the past three years, and have started a study of similar families in
Finland. “We don’t have data yet,” he said. “It would take many subjects to pick
out those genes.”
One working hypothesis is that there might be some hidden evolutionary
benefit to preterm delivery. “For maternal survival, it might be better to
deliver early,” Muglia theorized.
To support that notion he cited sickle cell anemia, a genetic condition more
common in blacks than whites. Carriers of two genes for the condition are at a
handicap, but it has been found that the presence of a single sickle cell gene
protects the carrier against malaria, Muglia noted.
“I’m not sure it really gives us definitive answers,” said Dr. Diane Ashton,
deputy medical director of the March of Dimes. “But it is one aspect that the
March of Dimes is looking at to assess the differences in premature births.”
There have been hints of a genetic factor, Ashton added, citing a study
indicating that black women were more susceptible to early rupture of the
“There is some evidence here, but this is one study, and until we have some
reproducible results I don’t think we can base our final opinion on just one
study,” she said.
A 2006 report by the U.S. Institute of Medicine found that 12.5 percent of
American babies were born at least three weeks ahead of their full-term delivery
date. Care for those babies costs the nation $26 billion a year, with some
requiring neonatal intensive care for two weeks.
Potential problems for premature babies include hearing loss, vision loss,
cerebral palsy and seizures. Such problems are most common in babies born before
32 weeks of pregnancy.
For more on premature babies, consult the March of Dimes.
By Ed Edelson
SOURCES: Louis J. Muglia, M.D., Ph.D, director, Washington University Center
for Preterm Birth Research, St. Louis; Diane Ashton, M.D., deputy medical
director, March of Dimes; February 2007 American Journal of Obstetrics and
Copyright © 2007 ScoutNews, LLC. All
Clinical Trial Diversity: The Need and the Challenge
Clinical trials (also called medical research and research studies) are used
to determine whether new drugs/treatments are both safe and effective. In
addition, they help researchers decide if a drug’s risks are worth its benefits
(risk/benefit ratio). The Food and Drug Administration (FDA) considers the
results from clinical trials in approving a drug or treatment. Once approved,
the therapy becomes available for doctors to prescribe to their patients.
New therapies are tested on people in clinical trials only after laboratory
and animal studies show promising results. It is a challenge for researchers to
recruit adequate numbers of clinical trial participants, and even more of a
challenge to recruit African Americans. This is a concern because there is
evidence that certain drugs have different effects on African Americans than
they do on Caucasians. This article addresses the following questions:
- Why don’t more African Americans participate in
- How can a person be sure that a clinical trial
- Does drug effectiveness vary across
- How can I participate in a clinical
- What questions should I ask before participating
in a clinical trial?
Why don’t more African Americans participate in
There is a general distrust of the
medical/healthcare system amongst some African Americans, and perhaps many,
based on personal experience. In addition, historical events have given African
Americans reason to mistrust clinical trials.
On July 26, 1972, the New York Times reported on what it called the “longest
running non-therapeutic experiment on human beings in medical history.”
Departing from their Hippocratic oath to “first, do no harm,” physicians from
the U.S. Public Health Service allowed nearly 400 poor, black sharecroppers with
syphilis to go untreated for forty years. These men from Macon County, Alabama
were told they were being treated for “bad blood.” However, they were all
actually part of the Tuskegee Experiment, which was designed to study the
progression of syphilis-a potentially fatal sexually transmitted disease.
Many health professionals and leaders in the black community cite the
Tuskegee Experiment as a factor contributing to low participation of African
Americans in routine preventive care, clinical trials, and organ donation.
However, we can be thankful that the Tuskegee Experiment did lead to a change
for the better in how medical research is done.
How can a person be sure that a clinical
trial is safe?
An Institutional Review Board (IRB) must
approve all studies involving human or animal subjects in advance. Complaints
should be addressed to the director of the study or the institution’s IRB.
Institutional Review Boards (IRB) are made up of physicians, ethicists,
religious leaders and other community leaders, and are required to look at
studies which are going to use human or animal subjects.
An IRB’s main responsibility is to protect the public from harm and look
carefully at each study’s methods to make sure the research is done in an
Does drug effectiveness vary across
There are many therapies to which African Americans
are known to respond differently than whites.1, 2 For example, some drugs are
less effective in African Americans (such as beta blockers for hypertension),
some cause increased adverse events (such as occurrence of angioedema with use
of ACE inhibitors), and some show both types of differences. 1, 2
One study 3 showed that although ACE inhibitors are particularly effective in
whites, but not African Americans. A combination of hydralazine plus isosorbide
dinitrate reduced the mortality of black patients. At the same time, white
patients given this combination of drugs showed no difference from placebo
(sugar pill). The study concluded that clinical trials involving large numbers
of black patients are needed to further clarify their response to therapy.
Another study compared enalapril therapy for heart failure among blacks and
whites.4 Enalapril therapy reduced the risk of hospitalization for heart failure
among white patients with left ventricular dysfunction, but not among similar
black patients. Again, the researchers concluded that their findings underscored
the need for additional research on the efficacy of therapies for heart failure
in black patients.
How can I participate in a clinical
Not all studies involve drugs; some long-term studies
will only ask you to have a physical and fill out some paper work every few
years. Other studies need “controls”-people who don’t receive the treatment so
the results of those receiving treatment can be compared with them. You have the
right to quit any study you become involved in at any time.
What questions should I ask before
participating in a clinical trial?
If you want to become
part of a clinical trial, ask questions about the risks and benefits of the
- What is the study about?
- Who put this study together?
- How/when will I learn the results?
- Who is going to be in this study?
- What will I get out of this study?
- How will I be protected from harm?
- How will my privacy be protected?
- What will I have to do?
- What will I leave behind through my participation?