High cholesterol may delay pregnancy

The researchers measured each prospective parent's cholesterol by testing a blood sample taken at the study's outset. Rather than measuring low-density lipoprotein, known as "bad" cholesterol and other cholesterol subtypes, the researchers measured the total and free amounts of cholesterol in the blood.

The researchers found that on average, those couples in which the female did not become pregnant during the study duration had the highest free cholesterol levels.

In general, high free cholesterol levels were correlated with longer times to pregnancy and lower fecundability odds ratios.

Couples in which each partner had a high cholesterol level took the longest time to reach pregnancy. Moreover, couples in which the woman had a high cholesterol level and the man did not also took longer to achieve pregnancy when compared to couples in which both partners had cholesterol levels in the acceptable range.

"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," Schisterman said.

The findings were published in the U.S. Journal of Clinical Endocrinology & Metabolism.