Down's Syndrome Births Drop in UK

Oct. 27, 2009— -- More accurate screening and an increase in the number of younger mothers being screened for Down's syndrome may have forestalled an expected increase in the number of babies born with the condition in the United Kingdom, a study shows.

From 1989 to 2008 in the number confirmed prenatal or postnatal diagnoses of Down's syndrome in England and Wales increased by 71 percent -- from 1,075 to 1,843 -- according to Dr. Joan Morris and Dr. Eva Alberman of Barts and the London School of Medicine and Dentistry.

However, the number of babies born with Down's syndrome remained relatively steady despite an increase the age of mothers -- there were 752 in 1989 and 743 in 2008 -- because of terminations following prenatal diagnoses, they reported online in the British Medical Journal. The termination rate remained unchanged.

Dr. James Goldberg of San Francisco Perinatal Associates, past chair of the American College of Obstetricians and Gynecologists' Committee on Genetics, said he didn't know whether there was a similar trend in the United States or in other countries.

He said he believes the situation would be much the same here, although at least one small study has shown an increase in the number of live Down's syndrome births over time in women older than 35.

A spokesperson for ACOG noted that there are no national U.S. data on the number of women who receive prenatal screening for Down's syndrome or reliable data on the number babies born with the disorder.

Morris and Alberman examined data from the U.K.'s National Down Syndrome Cytogenetic Register, which includes about 93 percent of all diagnoses of Down's syndrome in England and Wales.

The database included information on diagnoses in live births and stillbirths, as well as antenatal diagnoses and subsequent terminations, fetal losses, and a small number babies brought to term.

Over the 20-year study period, the large increase in diagnoses occurred even though the overall number of births remained constant.