More than 150 pregnant women may have been given incorrect results from a test for Down's Syndrome because of the Y2K software bug.

Between January 4 and May 24 last year, the PathLAN system at Northern General Hospital, which processed results of the screening of mothers at nine hospitals in South Yorkshire, Lincolnshire and the East Midlands, gave potentially incorrect results because of the Millennium bug.

After the year 2000 passed the ages of women were calculated incorrectly, which meant that many patients were informed wrongly that their babies were at low risk of the disease, according to a UK government report.

Four women subsequently gave birth to Down's Syndrome babies and two terminated their pregnancies.

If an error in calculating the women's age correctly had not been made during routine screening they would have been identified as high risk far earlier and offered a more conclusive amniocentesis test for Down's Syndrome far earlier in their pregnancy.

The delay caused by incorrect processing of data at Sheffield's Northern General Hospital meant that tests had to be conducted far later in pregnancy, putting mothers and babies at greater risk.

Professor Lindsey Davies, regional director of public health, who commissioned a 112-page report into the affair, blamed over-reliance on the PathLAN computer software used to perform the tests. The health services need to put increased safeguards in place.

PathLAN accesses the risk of a woman giving birth to a baby with Down's Syndrome based on her age, body weight, length into a pregnancy and blood test results. ®

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