Fatty ovaries can upset embryonic development and lead to failed pregnancies, research suggests. The findings, from a study on cow eggs, support advice to women to avoid being overweight if they want babies.

They may help explain why obese women and those with diabetes often struggle to conceive, say researchers.

These individuals tend to metabolise more stored fat, leading to higher fatty acid levels in the ovary.

The study involved exposing eggs from cows to high concentrations of saturated fatty acids.

Researchers discovered that embryos created from the fat-exposed eggs had fewer cells, and underwent changes in gene and metabolic activity. Lead scientist professor Jo Leroy, from the University of Antwerp in The Netherlands, said: “We know from our previous research that high levels of fatty acids can affect the development of eggs in the ovary, but this is the first time we’ve been able to follow through to show a negative impact on the surviving embryo.”