Data from the National Statistical Office confirms the trend: women who had their first child over age 40 increased from 0.1 percent of all child-bearers nationwide in 1990 to 0.5 percent in 2000 and 0.8 percent in 2005. The total percentage of women giving birth over 40 (to either their first or a subsequent child) has increased steadily, from 1.17 percent in 2003, 1.22 percent in 2004, and to 1.31 percent in 2005.

The reason behind the phenomenon, experts say, is that more Korean women want to work. When given a choice between the office and babies, more women are putting babies at less of a priority. Women who want a successful career tend to hesitate before getting married or having children.

The problem is that giving birth at an older age is not good for the health of the mother or the child. "It's difficult to get pregnant after 40, and then there's a higher risk of a deformed child or a premature delivery," said Professor Cho Jung-hyun of CHA Fertility Center. "It's essential to check for any problems in the chromosomes of the unborn baby." This is done through blood tests during the initial stage of the pregnancy and an amniocentesis at the 16th week.

"It's also more difficult to recover from the delivery at an older age, and there are sometimes problems with the production of breast milk," Professor Cho said. "If you're considering giving birth and raising a child, you shouldn't put off doing it for too long."

Despite the risks, Professor Bae Eun-kyung of the Department of Sociology at Seoul National University predicted the trend will continue. Since the struggle of women for social success isn't going to go away, Professor Bae said that husbands should be more willing to share the burdens of childcare and that public and corporate policies should be put in place to allow women to pursue both their careers and motherhood.