Does cholesterol levels influence IVF outcomes?

This study looked at cholesterol and other lipid (fats) levels in the blood in women undergoing in vitro fertilization (IVF). It found that women with more heart-healthy lipid levels had better IVF outcomes.

Lipid levels are an important measure of health. While a lipid can be any oily or waxy substance in the body, cholesterol is one of the most important. The liver creates cholesterol, which is needed for many bodily functions. All cells of the body use cholesterol to keep their cell walls flexible. Also, many hormones are made from cholesterol, including cortisol, estrogen, and testosterone.

Cholesterol cannot dissolve in water or blood. Instead, it is carried through the blood on floating proteins known as lipoproteins. Low-density lipoprotein cholesterol (LDL-C), sometimes called “bad cholesterol,” carries cholesterol from the liver out to the rest of the body. High-density lipoprotein cholesterol (HDL-C), or “good cholesterol,” brings the cholesterol back to the liver so it can be disposed of. If too much cholesterol is going out into the body, it can build up in the walls of the arteries. This increases the risk of heart attack and stroke.

Cholesterol is also important in reproduction. Both LDL-C and HDL-C are important in bringing cholesterol to the ovaries, which transform it into estrogen. Lipid levels in the lining of the uterus may affect how receptive it is to an embryo implanting. Also, during pregnancy, the placenta creates hormones for the baby using cholesterol from the mother’s blood.

Some studies have found that cholesterol and lipid levels may affect pregnancy rates for couples trying to conceive. However, it is not clear whether lipid levels affect the infertility treatment in vitro fertilization (IVF).

This study used records from 2011 women who used IVF or a related procedure, intracytoplasmic sperm injection (ICSI). All of the patients had their blood lipid levels tested before treatment. It was the first cycle of IVF or ICSI for all of the women. Most of the women had a normal weight (average body mass index of 21.7 kg/m²).

51.2% of the women had a pregnancy visible on ultrasound. Patients with low “bad” LDL-C had 41% higher odds of getting pregnant. Lower triglycerides and higher “good” HDL-C also significantly raised the odds of pregnancy. These results were adjusted for other factors, including body weight.

Patients with low LDL-C and high HDL-C were also significantly less likely to have a miscarriage. Women were divided into four groups based on their LDL-C levels. The patients with the lowest LDL-C had a 56% lower risk of miscarriage than average.

Low LDL-C, low triglycerides, and high HDL-C were all related to higher birth rates after adjusting for other factors. Patients with the lowest quarter of LDL-C had 2.22 times higher odds of having a baby.

This study found that low LDL-C, low triglycerides, and high HDL-C levels are related to better IVF outcomes.

It is not fully understood how blood lipid levels influence fertility and IVF outcomes. While the study adjusted for body weight, other factors such as diet may also be important.

Ask your doctor about whether your lipid levels are in a healthy range.