BEIJING - Less than 10 percent of couples in the capital city get premarital health checkups, and this has led to an increase in birth defects over the past five years, according to a city health official on Friday.

Most people consider these checkups unimportant because they are no longer a prerequisite for registering for marriage, said Lu Fan, director of mental health and maternity and child healthcare under the Beijing municipal health bureau.

A survey conducted by the bureau in 2010 found that nearly half of the people who skipped premarital health checkups did so because they were not mandatory, 17 percent skipped because they were inconvenient and 30 percent because of the financial burden, Lu said.

The central government made the checkups optional in 2003.

Since then, the incidence of birth defects has risen in Beijing, Lu said, and by the end of 2010 was almost double that of 2005.

She did not give exact statistics on birth defect rates in those two years.

Earlier media reports said that the city's birth defect rate was 170.82 for every 10,000 in 2008, compared with 90.78 in 1997.

Xia Yuting, a 27-year-old Beijing resident, told China Daily that she and her husband skipped the health checkup when they registered as a couple in April.

"Both my husband and I had to rush back to work on the day we registered, and we don't plan to have a baby soon," Xia said.

"Besides, no one at the registration office ever mentioned the checkup when we registered," she said.

The increase in the birth defect rate can be due to many factors, Lu said, and part of the increase could in fact indicate merely a higher detection rate because of improvements in medical technology, she added.

Premarital medical examinations, which help assess reproductive health and genetics, include routine hematology and urine tests and tests for HIV/AIDS.

"We intend to work with the civil affairs authority to better inform the public about the significance of the premarital health checkups and improve our medical services to reverse the trend," Lu said.

Lu made the remarks at a news conference for the release of the municipal government's 12th Five-Year Working Plans for Women and Children on Friday.