(RxWiki News) Many couples hoping to start a family expect to become pregnant quickly, but that’s not always the case. There's one surprising reason that might explain why some couples take longer than others.
A new study found that couples with high cholesterol levels took longer than those with lower levels to become pregnant, or they did not become pregnant at all.
"Tell your doctor if you're having trouble conceiving."
This study was led by Enrique Schisterman, PhD, of the Eunice Kennedy Shriver Institute of Child Health and Human Development in Rockville, Maryland.
The researchers enrolled 501 couples hoping to become pregnant between 2005 and 2009. These couples were from Michigan and Texas, and were part of the Longitudinal Investigation of Fertility and Environment (LIFE) Study.
The women were aged 18 to 44, and the men were 18 or older. They were followed for 12 months or until they had a positive pregnancy test.
During the study, 347 couples (67 percent) became pregnant, while 54 couples did not. The final 100 couples withdrew from the study for various reasons, such as deciding not to become pregnant at that time.
The couples had blood tests that measured their free cholesterol, which is total cholesterol in the blood. The test does not distinguish between types of cholesterol, such as LDL (low-density lipoprotein) or triglycerides.
After accounting for the possible role of body fat in the differences between those who conceived and those who could not, Dr. Schisterman and team found that couples with the highest total cholesterol either took longer to become pregnant than those with lower cholesterol levels or did not become pregnant.
Couples in which the female had high cholesterol levels and the male did not also took longer to become pregnant or did not successfully conceive.
The study's authors did not identify the exact mechanism behind the troubles conceiving among those with high cholesterol, but they did note that cholesterol plays a role in the production of steroids, which may contribute to these findings.
The authors noted that this was the first study to find that serum cholesterol may reduce a couple’s ability to have children or may make it take longer to become pregnant.
Currently, infertility may affect as much as 15 percent of men and 17 percent of women in the United States, and managing cholesterol in some of these people may help them become pregnant, the authors wrote.
"We would recommend that couples trying to conceive adopt a healthy lifestyle, particularly diet and exercise to maintain healthy levels of cholesterol," Dr. Schisterman told dailyRx News.
"Oftentimes, people fear that by lowering cholesterol, they may inadvertently cause other problems to arise. We know that cholesterol is an important component of many of the hormones involved in reproduction. However, typical levels in the US are unnaturally high due to diet high in unhealthy fats and processed foods. Obesity and a sedentary lifestyle also contribute," Sarah Samaan, MD, cardiologist and physician partner at the Baylor Heart Hospital in Plano, Texas, explained to dailyRx News.
"This study suggests that higher cholesterol levels contribute to infertility, and that it's likely that by lowering cholesterol levels, fertility may also improve," Dr. Samaan said.
"For most adults of childbearing age, making heart smart lifestyle changes will go a long way towards improving cholesterol levels. In general, women who are considering pregnancy should not take cholesterol medications, since there is no proof that these drugs are safe during pregnancy," she said.
This study was published May 20 in The Journal of Clinical Endocrinology and Metabolism.
The authors did not disclose any conflicts of interest.