Friday, October 14, 2005

Maternal Blood Test Might Reveal Fetal Health

Maternal Blood Test Might Reveal Fetal Health
Early research points the way to safe, accurate prenatal screen

FRIDAY, Oct. 7 (HealthDay News) -- New research is moving scientists closer to the holy grail of prenatal medical care: a maternal blood test that could reveal health problems in an unborn child.

Researchers from Hong Kong reported this week that they've discovered a potential new way to differentiate the DNA of the mother from that of the fetus in a maternal blood plasma sample. The key, they say, lies in a DNA trait that's much more common in maternal genetic material.

Specialists couldn't predict how long it may take for the findings to translate into a routine fetal DNA screening test available in the doctor's office. And the study results don't appear to have any bearing, at least for now, on controversial fetal DNA tests that promise to predict a baby's gender early in pregnancy.

Still, the research is promising, said Dr. Siobhan Dolan, associate medical director at the March of Dimes. "This study is a step in the right direction," she noted.

Currently, the best screening tests for fetal medical problems -- including amniocentesis -- are also potentially dangerous to the unborn child. Doctors and researchers have been looking for a noninvasive test, and a test using the mother's blood would certainly fit the bill (current blood tests for pregnant mothers don't directly measure the health status of the fetus).

The good news is that a small bit of fetal blood does blend in with the mother's blood. "The trick is to find a way to sort out in the blood what came from the fetus and what came from the mother," Dolan said.

Only about 3 percent of DNA in maternal blood plasma comes from the fetus, said study author Dennis Lo, a professor of chemical pathology at the Chinese University of Hong Kong. There are ways to differentiate the fetal DNA, such as looking for the male Y chromosome, he said, but that only works for male fetuses.

In the new study, Lo and his colleagues report that they can differentiate maternal from fetal DNA by looking for a specific gene that acts differently in mothers and fetuses. They also used their technique to accurately detect cases of pregnancy-associated hypertension, also known as preeclampsia, in pregnant women.

The findings appear in this week's early online edition of the Proceedings of the National Academy Sciences.

Earlier this year, researchers reported that they were able to more easily analyze fetal DNA by boosting its levels in blood samples. Scientists have also found a way to separate bits of maternal and fetal DNA by analyzing their size.

The new research may have implications for existing fetal DNA tests, such as those that detect potentially dangerous blood group incompatibilities between mother and fetus, Lo said. It's not yet known if the tests will help pick up other diseases like Down syndrome, but researchers are hopeful, Lo said.

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New Insights into Preemie Infant Brain Injury

New Insights into Preemie Infant Brain Injury
Neurological damage once considered harmless may not be, study suggests

MONDAY, Oct. 3 (HealthDay News) -- A part of the brain called the cerebellum -- previously believed to be principally involved in motor coordination -- also plays an important role in the development of behavior and cognition, new research reveals.

Experts at Children's Hospital Boston used MRI to study the brains of 47 premature babies. Cerebellar injury is increasingly recognized as a potentially serious complication of premature birth.

Reporting in the October issue of Pediatrics, they found that cerebellar injury can have a major impact on development, and that the cerebellum and another part of the brain, the cerebrum, are tightly interconnected. It's long been believed that the cerebrum is the primary location of higher cognitive functions such as language and visual processing.

The Boston team found that when the cerebrum was injured, the cerebellum failed to grow to a normal size. And when the cerebellar injury was limited to one side, the opposite cerebral hemisphere did not grow to normal size.

"There seems to be an important developmental link between the cerebrum and the cerebellum. We're finding that the two structures modulate each other's growth and development. The way the brain forms connections between structures may be as important as the injury itself," study author and neurologist Catherine Limperopoulos said in a prepared statement.

"Until recently, cerebellar injury was underrecognized. Doctors downplayed it, saying 'Oh, maybe Johnny will be a little clumsy,'" she said. "Our research has made us aware that cerebellar injury is not a benign finding. We now know to look for it, and can counsel families that their children are likely to have deficits that extend beyond motor, and that may benefit from early intervention."

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Vaccine Might Shield Newborns from Infection

Vaccine Might Shield Newborns from Infection
Study will examine whether vaginal bacteria can be suppressed during childbirth

THURSDAY, Sept. 29 (HealthDay News) -- U.S. researchers are conducting a study to determine if a new vaccine can protect newborn babies from potentially lethal infection.

The infection is caused by common bacteria called group B strep that live harmlessly in the gastrointestinal tract and vagina of 25 percent of women. Exposure to these bacteria during birth can trigger potentially lethal infections in newborns, however.

"If we could give a vaccine to prevent women from harboring group B streptococcus in the vagina, then babies are not going to get it," Dr. Daron Ferris, a family medicine physician at the Medical College of Georgia and principal investigator of the U.S. National Institutes of Health study, explained in a prepared statement.

The 18-month study of 600 healthy, non-pregnant women will compare the effectiveness of the vaccine -- which was developed at Harvard University -- with a standard tetanus toxoid vaccine in controlling group B infections in the study participants.

Group B strep is the most common infectious cause of death in newborn babies, according to the U.S. Centers for Disease Control and Prevention. Infection-related problems typically occur in the first week of life when a baby's immune system is immature and unable to fight off infection. The bacteria can cause septicemia, meningitis, pneumonia and long-term hearing and vision damage in infants, as well as developmental problems.

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Immune Drug May Prevent Fetal Infection

Immune Drug May Prevent Fetal Infection
Hyperimmune globulin cut rate of mom-to-child transmission of cytomegalovirus

THURSDAY, Sept. 29 (HealthDay News) -- A drug that boosts a woman's immune system during pregnancy may help prevent her from passing along a common but dangerous virus to her unborn baby, Italian researchers report.

The drug, called hyperimmune globulin, cut rates of mother-to-child transmission of cytomegalovirus (CMV) to just 3 percent of babies born to women infected with the virus.

In contrast, 50 percent of infected mothers who did not receive the treatment passed on the potentially harmful pathogen to their newborn.

"Hyperimmune globulin was effective in treating and preventing mothers from transmitting the infection," said study co-author Dr. Stuart Adler, a professor of pediatrics and chairman of infectious disease at the Medical College of Virginia Campus of Virginia Commonwealth University in Richmond.

His team published their findings in the Sept. 29 issue of the New England Journal of Medicine.

Cytomegalovirus is a very common infection that is usually harmless for adults and children, according to experts at the March of Dimes. About half of the U.S. population will have contracted CMV by the time they're 30.

But the virus can cause grave harm to newborns. About 1 percent of all babies born in the United States are born with congenital cytomegalovirus, an infection that varies in severity from causing no symptoms to causing severe neurological problems and even death.

There's currently no effective treatment for the infection, and if a mother is infected with the virus during pregnancy, there's about a 40 percent chance that she'll pass the infection on to her offspring.

Hyperimmune globulin is a type of immunotherapy designed to boost the maternal immune system. For the current study, CMV-specific hyperimmune globulin was used to ramp up the immune system against this particular threat.

Adler said the researchers suspected the CMV-specific hyperimmune globulin would work in humans because of prior research in human cell cultures and animals. The therapy is considered very safe, and no adverse effects have been noted.

Because the therapy is considered so safe for women and the consequences of an active CMV infection can be so severe for newborns, the study was not randomized and women were offered the option to receive treatment.

Pregnant women were recruited for the study from eight Italian cities. Women with active CMV infection were then separated into either a therapy group or a prevention group.

The therapy group included 45 women who had an active CMV infection, as did their babies. All babies were tested via amniocentesis. Thirty-one of these women elected to receive treatment with hyperimmune globulin, and 14 chose not to receive the therapy.

Only one woman (3 percent) in the therapy group gave birth to an infant with CMV disease, defined as a displaying symptoms of infection at birth and being in some way handicapped at 2 years or older.

In contrast, seven women (50 percent) of the women who weren't treated gave birth to babies with CMV disease.

The "prevention" group included 84 women with CMV infection who chose not to undergo amniocentesis, so the researchers didn't know whether or not these babies were infected. Thirty-seven of these women chose to receive hyperimmune globulin, compared to 47 women who declined.

Six out of the 37 women (16 percent) who received treatment delivered babies with congenital CMV vs. 19 out of 47 women (40 percent) who did not receive the treatment.

"This new therapy is very exciting because there has been no effective therapy for protecting babies from CMV," said Dr. Patrick Duff, from the University of Florida College of Medicine in Gainesville, and author of an accompanying editorial.

However, Duff added, "There's still room for caution here. This study didn't include a huge number of patients, and it wasn't randomized." He also noted that screening tests for CMV aren't 100 percent accurate and therapy with hyperimmune globulin is expensive. "There are still some loose ends," he said.

Both Adler and Duff said additional studies need to be done to confirm these findings.

In the meantime, Adler believes women who are pregnant or thinking of becoming pregnant should be screened for CMV -- especially if they are at high risk for infection. High-risk groups include women who spend a lot of time with young children, such as a teacher or day-care worker or a mother of a young child under the age of 2 or 3, he said.

Women who test seronegative -- meaning they've never had the disease -- need to take precautions to lessen the chance of getting infected with CMV while they are pregnant. This means frequent and thorough hand washing and avoiding intimate contact with youngsters -- no kissing on the lips or sharing eating utensils. Women who test seropositive -- meaning they've had the infection at some point in the past -- are at extremely low risk of passing any active infection onto their baby, however.

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Fewer Women Taking Folic Acid Supplements

Fewer Women Taking Folic Acid Supplements
The B vitamin helps prevent birth defects, researchers say

THURSDAY, Sept. 29 (HealthDay News) -- The number of American women taking folic acid supplements to prevent serious birth defects of the brain and spine decreased from 40 percent in 2004 to 33 percent this year, according to a new report from the March of Dimes.

The report appears in the Sept. 30 issue of the U.S. Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Report.

"We have found that over the years the percentage of women reporting taking a vitamin containing folic acid every day has gone back down to 33 percent in 2005," said report co-author Heather Carter, a CDC nutrition epidemiologist.

The researchers also found that the percentage of women who were aware of folic acid increased from 78 percent in 2004 to 84 percent in 2005.

While awareness increased, the percentage of women who know that folic acid prevents birth defects remained unchanged at 25 percent. And the percentage of women who know that folic acid should be taken before pregnancy dropped from 12 percent in 2004 to just 7 percent in 2005, the lowest percentage since 1997, according to the survey.

There are number of reasons why women don't take folic acid supplements, Carter noted. "The most common reason for not taking a vitamin is forgetting to take it," she said. "Twenty-eight percent say they forget to take a vitamin."

Many women also think they don't need to take a vitamin, Carter said. "Some women also believe that they can get the vitamin from the food they eat," she said. "We need to motivate women to take either a vitamin supplement or get folic acid from fortified foods."

Women of childbearing age are advised to take folic acid, a B vitamin, every day. Folic acid can also come from vitamin pills or foods such as enriched breads and cereals, leafy green vegetables and citrus fruits.

"Every women of childbearing age needs to be consuming a vitamin containing 400 micrograms of folic acid every day to try to prevent serious birth defects of the brain and spine," Carter stressed.

These birth defects most often include the neural tube defects spina bifida and anencephaly (incomplete brain formation). These birth defects, occurring in an estimated 3,000 pregnancies in the United States each year, can cause lifelong disability or death, according to the CDC.

One expert agrees with the importance of getting enough folic acid, and thinks that women can get the folic acid they need by eating vitamin-enriched foods.

The difficulty in getting all women of childbearing age to get enough folic acid owes to a combination of education and economics, said Tsunenobu Tamura, a professor of nutrition science at the University of Alabama.

"However, if women are eating enriched grain products like bread and cereal, they should get folic acid in addition to the folic acid they are getting from regular food," Tamura said.

Tamura encourages women to get folic acid from foods. "If you go to the grocery story you should select items that contain enriched flour to get folic acid," he said. "If women get folic acid through enriched foods, they may not need to take folic acid supplementation."

But another expert thinks that taking a supplement is the best way to guarantee that women are getting enough folic acid.

"To ensure that women get 400 micrograms of folic acid daily, the most assured way is though a multivitamin supplement," said report co-author Joanne Petrini, director of the perinatal data center at the March of Dimes Birth Defects Foundation.

There are probably not a lot of women getting the required amount of folic acid through diet, Petrini said. "Only a third are getting it through supplements, which means that 70 percent don't," she added.

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