Considering in vitro fertilisation? Then let nutrition boost your success rate: according to new research, a diet lower in carbohydrates and higher in protein may have a favourable impact on embryo quality and therefore IVF outcome.

Study details

Lead researcher Jeffrey Russell, MD, explained that his team looked at the developing eggs and embryos of women who attended his IVF programme. The scientists observed poor quality embryos among healthy women with a normal body weight and decided to investigate how nutritional components of a woman’s diet, rather than BMI, correlate with fertility.

Between January 2010 and December 2011, the researchers asked women undergoing IVF treatment to fill in a three-day diet journal prior to the embryo transfer, which was then analysed to determine their daily intake of carbohydrates, fats and proteins.

Study findings

The nutritional analysis revealed that 48 women had an average daily intake of at least 25% of total calories from protein while the remaining 72 had less than 25%. For some of these women, carbohydrates made up a whopping 60 to 70% of total calories.

Among these 48 women, 32 (67%) became pregnant compared to only 23 (32%) of the participants who consumed less dietary protein. The researchers also found that the clinical pregnancy rate increased by as much as 80% with lower carbohydrate intakes — less than 40% of total calories — and at least 25% of total calories from protein. The lower carbohydrate diets appeared to improve embryo quality and the number of embryos available for transfer.

The researchers found no difference in BMI between the two groups and concluded that although excessive or insufficient body fat stores reduce fertility, the overall dietary intake also affects pregnancy outcome irrespective of BMI.

Study implications

Dr Russell explained that “protein is essential for good quality embryos and better egg quality.” The researchers speculate that elevated blood glucose concentrations caused by high carbohydrate diets create an adverse environment for the egg even before fertilisation.

“Although the blood glucose is not high enough to be in the diabetic range, it is enough to be toxic to the developing blastocyst,” Sharon Phelan, MD and member of the American College of Obstetricians and Gynecologist (ACOG) Scientific Program Committee told Medscape Medical News.

It is also possible that the women who had a higher protein intake automatically ate fewer processed foods, which are typical of the Standard American Diet. Processed foods are often rich in simple sugars and trans fats both of which have adverse effects on fertility.

Experts warn that this study’s findings do not mean that women with fertility issues should gorge on steaks, eggs and cheese but that they should pay attention to what they “feed” their eggs.

The study’s findings were presented at the 2013 Annual Clinical Meeting of the ACOG.


    Russell et al. Daily protein content correlates with increased fertility and pregnancy outcome. ACOG 2013. Abstract Poster 96.