Research in the US has shown that when one or both people in a couple have high cholesterol it takes significantly longer for the woman to conceive. However, a woman’s cholesterol level is more important, as a man with high cholesterol does not significantly delay pregnancy if the woman’s cholesterol reading is within the normal range, according to the study conducted by the National Institutes of Health, the University at Buffalo and Emory University in Atlanta.
High cholesterol levels are often caused by poor diet. Cholesterol helps to produce hormones, such as oestrogen and testosterone, required in conception, but too much or too little of the hormones can hinder the conception process and so a delicate balance must be struck.
According to the study’s author Enrique Schisterman of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, men and women need “optimal amounts” of cholesterol.
Dr Schisterman said people who want to have children should focus on living a healthy lifestyle and keeping cholesterol levels down. Dublin-based senior clinical embryologist Declan Keane said the research is further evidence of the importance of nutrition to conception.
The director of Repro Med fertility clinic in Dublin said that food intake is important for “sperm integrity”, which ensures quality of sperm and lowers risk of miscarriage. It is also vital for female egg quality, with high cholesterol increasing the risk of lowered fertility and miscarriage.
“Up to 40% of the patients who come to me seeking IVF having been trying for a child for two or three years but may need help with their nutritional intake,” said Dr Keane.
“I often have to beg them to wait two or three months so I can work on issues like their weight and diet rather than going straight for IVF. If somebody has a body mass index of over 30, they will have a much better chance of conceiving if they can reduce that BMI to below 30.”
Dr Keane also said “gut health” is important, as a healthy intestine ensures that vitamins and minerals are absorbed properly.
Dr Keane added that while sperm quality drops after the age of 48, egg counts start to fall rapidly after the age of 36.
In the US study, the researchers studied up to 501 couples who wanted to conceive, for a year or until pregnancy. Even when they controlled for other factors associated with infertility in the past, such as a high body mass index, high cholesterol clearly proved an additional problem, said Dr Schisterman.