A new study finds that couples who have difficulties in conceiving a child should seek medical help as soon as possible. Otherwise, they could dramatically reduce their chances of having a baby. The study suggests that every month of delay in getting pregnant reduces a woman's chance of conceiving subsequently.

Researchers at the Karolinska Institutet in Stockholm analyzed data from 2,000 women over the age of 30 who were trying to get pregnant. They found that after 12 months of trying, 82 percent of women had become pregnant. However, only 66 percent of women who had been trying for 24 months had conceived. And just 43 percent of women who had been trying for 36 months had become pregnant.

The study also found that women who had underlying medical conditions such as endometriosis or polycystic ovary syndrome were even less likely to conceive after delays in trying to get pregnant. For example, after 12 months, 68 percent of women with endometriosis had become pregnant, compared with 82 percent of women without endometriosis.

"Our study shows that the longer a couple waits to seek help for infertility, the lower the chances of conceiving," said Dr. Kristina Gemzell-Danielsson, lead author of the study. "This is especially true for women with underlying medical conditions."

Dr. Gemzell-Danielsson said that couples who have been trying to conceive for more than 12 months should seek medical help. "It is important to seek help as soon as possible, so that any underlying medical conditions can be diagnosed and treated," she said.

The study was published in the journal Fertility and Sterility.