'Birth defects more common in boys'

Birth defects have been found to be more common among boys than girls, according to a report.

And the most commonly occurring defect is hypospadia, an abnormally placed urinary opening in the male urethra.

Conditions that affect both sexes, but are more prevalent in boys, include congenital heart diseases, oesophageal defects and kidney cysts. Chromosomal abnormalities, such as Down syndrome, are the second-most commonly reported congenital anomalies.

"For every 10,000 babies born during 2002-2003, about 11 were born with Down syndrome," said Samanthi Abeywardana, author of the Australian report.

"When terminations of pregnancies were included, the total estimated rate for Down syndrome was just over 26 per 10,000 pregnancies - an increase from previous reports."

The risk of having a baby with Down syndrome increases with age, from one in 1,500 for mothers aged 20-24, to one in 184 for women 40 and over.

The estimated prevalence of neural tube defects was about 10 per 10,000 pregnancies, about 13 per cent less than the 1998-2001 period.

The rate of anencephaly, the most severe form of neural tube defect, which is always fatal, declined from 5.1 per 10,000 pregnancies in 1998 to 3.8 per 10,000 pregnancies in 2003 - a 25 per cent reduction.

A higher overall rate of congenital anomalies was reported for the births to indigenous women compared with non-indigenous women (356 per 10,000 births versus 308 per 10,000 births).