By Thaddeus M. Baklinski

LONDON, November 9, 2009 ( – The number of Down syndrome pregnancies in the UK has nearly doubled over the past 20 years, whereas the number of Down syndrome births has slightly declined, with the vast majority of such pregnancies ending in abortion, according to a study published Oct. 26 in the British Medical Journal.

University of London researchers found the number of confirmed prenatal or postnatal diagnoses of Down syndrome increased by 71 percent between 1989 and 2008, from 1075 to 1843.

However, live births of babies with Down syndrome fell about 1 per cent, from 752 to 743 over the time period. Though the proportion of mothers diagnosed with a Down syndrome baby who decided to abort their child remained constant at 92 percent, the increased numbers of babies being diagnosed with the syndrome means the actual number of abortions rose sharply.

Dr. Joan Morris and Dr. Eva Alberman analyzed data from the U.K.’s National Down Syndrome Cytogenetic Register, which includes approximately 93 percent of all diagnoses of Down syndrome in England and Wales.

The research pointed to maternal age playing a large part in the increased number of Down syndrome pregnancies. The trend toward later motherhood has resulted in a higher risk of having a child with Down syndrome, with the research estimating that the risk for a 40-year-old mother is 16 times that for a 25-year-old mother.

With many women delaying motherhood until their thirties and forties, most are encouraged by the medical profession to undergo screening for Down syndrome, usually with the intention of abortion if the test reveals the condition.

The initial screening test consists of an ultrasound scan and blood tests, but these tests are by no means accurate or conclusive. If Down syndrome is suspected, an amniocentesis, which uses a needle to extract fluid from the womb for analysis, is carried out. This test carries a roughly 1 in 100 chance of injuring the child in the womb with a consequent miscarriage.

Official figures for 2008 from the UK’s Office of National Statistics show that nearly half of all births in England and Wales were to women aged over 30, compared to just 28 per cent in 1986.

Professor Morris said, “What we’re seeing here is a steep rise in pregnancies with Down syndrome but that is being offset by improvements in screening. It was thought that these improvements would lead to a decrease in the number of births with Down’s Syndrome. However due to increases in maternal age this has not occurred.”

“In the absence of such screening, numbers of live births with Down syndrome would have increased by 48 per cent, since couples are starting families at an older age,” she said.

The researchers noted a sharp increase in the proportion of Down syndrome pregnancies in women under the age of 37 being detected by screening, rising from three percent to 43 percent within the time frame of the study, while the figure for women over 37 remained constant at around 70 percent.

“The proportion of antenatal diagnoses has increased most strikingly in younger women, whereas that in older women has stayed relatively constant. This trend suggests that, even with future improvements in screening, a large number of births with Down syndrome are still likely, and that monitoring of the numbers of babies born with Down syndrome is essential to ensure adequate provision for their needs,” the study reported.

See LSN articles related to the abortion of Down syndrome children:

Commentary: Will Babies with Down Syndrome Just Disappear?

New Effort Launched to Decrease Eugenic Abortion of Down Syndrome Babies

95% of Spanish Down’s Syndrome Children Aborted After Prenatal Testing

British Abortion Rate Skyrockets as Couples Eliminate “Defective” Children