Safer Down Syndrome Tests
Researchers seeking a safer way to detect Down syndrome in a fetus say that combining blood and ultrasound tests from the first and second trimesters would be more accurate than standard screenings and would reduce the need for riskier testing.
The method would spare many women the need for a definitive test called amniocentesis, in which a needle withdraws fluid from the amniotic sac. That triggers miscarriage about 1 percent of the time.
Compared with the testing that is standard in the United States, the new system would prevent the miscarriages of about 1,400 healthy fetuses each year and detect about 800 more fetuses with the chromosomal abnormality, said Nicholas Wald of the Wolfson Institute of Preventive Medicine in London, the lead researcher.
The screening also could reassure expectant parents their baby does not have Down syndrome, a condition in which an extra chromosome causes mental retardation and physical abnormalities.
About 1 in 700 babies has Down syndrome, which is marked by a broad, flat face with slanting eyes--and an early death..
Wald and colleagues developed a complicated computer program that integrates results of tests in both trimesters. First, a woman is given an ultrasound and a blood test for a protein linked to Down syndrome, both done 10 to 14 weeks into the pregnancy. A month later, she has blood tests for abnormal levels of four substances associated with a high risk for Down syndrome. Wald's research is reported in today's edition of the New England Journal of Medicine.
Hay Fever Shots Persist
The protection against sniffles, runny nose and sneezing that monthly allergy shots provide to hay fever sufferers persists long after the injections cease, according to a new study.
In tests on 47 volunteers, a research team led by Stephen R. Durham of the National Heart and Lung Institute in London found that "three to four years of grass-pollen immunotherapy remains effective for at least three years after the discontinuation of the injections."
Researchers need to discover if the shots, if started early enough, can prevent a person's allergies from getting worse over time or halt the development of multiple allergies. Such experiments, the Durham group said, must be conducted with children to determine if the injections can ward off long-term misery.
The new work, in today's New England Journal of Medicine, "provides the best evidence to date that [the treatment] has long-term, perhaps permanent, benefits," according to an editorial by Franklin Adkinson Jr. of the Johns Hopkins School of Medicine in Baltimore.
Hay fever, also known as allergic rhinitis, typically appears around age 10 and can progressively worsen. It affects 10 percent to 20 percent of the population in the United States, Adkinson said.