Mother's fat can harm embryos - at least in cows

European researchers have shown a correlation between impaired embryo development and the fat levels of mother cows. Exposing eggs to high levels of saturated fatty acids affected the health of embryos produced by fertilising those eggs. These findings may shed light on the fertility problems faced by women with type 2 diabetes and obesity whose ovaries are known to contain increased levels of saturated fatty acids.

'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', said Professor Jo Leroy of the University of Antwerp, Belgium, who led the study.

Researchers analysed eight-day old embryos taken from cattle exposed to high levels of saturated fatty acids. These embryos had fewer cells, increased expression of genes associated with stress, and increased metabolic activity – all of which pointed towards reduced viability. This may explain why women with obesity and type 2 diabetes have difficulty conceiving, as in both conditions increased metabolism of stored fat is common, leading to increased fatty acid levels in the ovaries.

'In cows we can induce very similar metabolic disorders leading to reduced fertility in these animals and compromised egg quality in particular. This is one of the reasons that bovine eggs are a very interesting model for human reproductive research', said Professor Leroy.

Future research aims to investigate these findings in humans and determine if detrimental effects of high maternal fat levels can be detected after birth. Dr Roger Sturmey of the University of Hull, who was also involved in the study, said: 'Our findings add further weight to the public health recommendations which emphasise the importance of women being a healthy weight before starting a pregnancy'.

This study was published in the journal PLoS ONE.