TOKYO — More than 40% of women who have gone through pregnancy have experienced miscarriages, a survey by a health ministry research group showed Sunday. The group under the Health, Labor and Welfare Ministry also said around 80,000 women a year are believed to be diagnosed as having had repeat miscarriages or stillbirths, and end up not having children.

"We have found that miscarriages happen more frequently than people assume," said Mayumi Sugiura, professor at Nagoya City University who was involved in the research under the ministry.

Sugiura also said that women who have repeatedly experienced miscarriages or stillbirths can still have children if they undergo the appropriate treatment, and urged them to be examined to determine the cause of the problem.

The group conducted the survey on women aged 35 to 79, who underwent health checkups in Okazaki, Aichi Prefecture, during a one-year period from February 2007.

Of the 503 respondents, 458 had experienced pregnancy, of whom 190, or 41.5%, had suffered miscarriages, according to the group.

Based on the survey outcome and other data, the group estimated that around 79,000 women are believed to experience repeat miscarriages or stillbirths annually.

Most miscarriages are caused by chromosomal abnormality in the fetus, a natural phenomenon that occurs at a uniform rate, so it is likely that a woman could have a baby with her next pregnancy, according to Sugiura. Some types of miscarriage could be averted by drugs.

"Many women give up on having a baby due to mental fatigue following repeated miscarriages," Sugiura said. "But they should be encouraged to go through pregnancy again if they can determine the cause of miscarriages."