Suffering from high cholesterol can cause infertility and delay pregnancy, latest research shows.Flickr/John Mayer

Suffering from high cholesterol can cause infertility and delay pregnancy, latest research shows.

In the study, the total amount of free cholesterol in each partner's blood was directly linked to the total time they took to fulfil their baby dreams. Couples, who failed to conceive even after trying for one year, had higher levels of free cholesterol in their blood than others.

Researchers based their findings on 501 couples who were trying for a baby, between 2005 and 2009, in the U.S.

Dr Enrique Schisterman and colleagues collected blood samples from the participants and measured total amount of free cholesterol in their blood. The test differed from the normal cholesterol tests based on HDL (high-density lipoprotein) or the good cholesterol, LDL (low-density lipoproteins) or the bad cholesterol and triglycerides (a kind of fat found in blood).

Using a statistical measure called fecundability odds ratio (FOR), researchers measured serum cholesterol concentrations of the couples and assessed their chances of pregnancy in each cycle. Results showed that high cholesterol levels left an adverse impact on fertility, extending and lowering chances of conceiving. Couples with high free cholesterol levels took more time to become pregnant than others.

Couples in which the female had a high cholesterol level and the male did not also took longer to achieve pregnancy when compared to couples in which both partners had cholesterol levels in the acceptable range.

Cholesterol, the waxy-fat like element, plays a major role in the production of sex hormones testosterone and oestrogen in both men and women, researchers said, while explaining the link between the two.

"We've long known that high cholesterol levels increase the risk for heart disease," first author of the study, Dr Schisterman, from the National Institute of Child Health and Human Development (NICHD), said in a news release. "In addition to safeguarding their health, our results suggest that couples wishing to achieve pregnancy could improve their chances by first ensuring that their cholesterol levels are in an acceptable range."

Findings of the study have been reported in The Journal of Clinical Endocrinology and Metabolism (JCEM).