Couples with high cholesterol levels may have to wait longer to become parents, a new study finds Newsmaxhealth reports.

When both the prospective mom and dad had high cholesterol levels, it took longer to conceive compared to those with lower cholesterol levels. The study also found the highest cholesterol levels among the couples who didn't achieve pregnancy during the year-long study. Cholesterol is a waxy substance that can build up in the body's blood vessels, according to the U.S. National Heart, Lung, and Blood Institute. Genetics and your family history play a role in your cholesterol levels, but so too, do diet and exercise, the institute says. Schisterman noted that when both the man and the woman have high cholesterol it takes much longer to conceive. Schisterman noted that while this study shows an association between cholesterol levels and time to conception, what isn't known is whether high cholesterol causes the delay.

It's also not clear if taking drugs to lower cholesterol would shorten the time to conception.

Also, it's possible that diet and exercise, which are known to lower cholesterol, might also reduce the time to conception, Schisterman said. Dr. Alan Copperman, director of the division of reproductive endocrinology and infertility at Mount Sinai Hospital in New York City, said, "People who are trying to get pregnant should optimize their health."

This includes not smoking, exercising, eating a healthy diet and maintaining a healthy weight. Whether cholesterol by itself affects fertility isn't clear, Copperman said.

For the study, Schisterman and colleagues collected data on 501 couples who were trying to have a baby. These couples took part in the Longitudinal Investigation of Fertility and the Environment (LIFE) study, which was designed to examine the relationship between fertility and exposure to environmental chemicals and lifestyle.

At the start of the study, the researchers measured each couple's cholesterol levels. The investigators found that couples took significantly longer to become pregnant when both partners or the woman had high cholesterol levels.

Among the couples, 347 conceived over the year of the study. Fifty-four couples didn't conceive. One hundred couples withdrew from the study, including some whose plans to have a child changed.