Researchers have warned that women who are overweight upon conception are at higher risk of having unhealthy embryos, with lower survival chances and major health problems during later life.
This first study of its kind shows the huge disparity in early embryo development between women who are a healthy weight and those who are overweight or obese.
Researchers based at the Hull York Medical School (HYMS) and the Hull IVF Unit, said that even the eggs of fat women appear to be smaller which places risk on the chances of a pregnancy being successful.
About 15% of mothers in the UK are obese during pregnancy, which is a 7% increase compared to 20 years ago.
Doctors have warned that the obesity epidemic among pregnant females is a burden on the NHS and a threat to the health of the next generation.
However, this is the first instance where potentially harmful changes at the point of conception have been linked to the mother’s weight.
According to Dr Roger Sturmey, from the HYMS Centre for Cardiovascular and Metabolic Research at Hull University, previous studies have shown that the weight of the mother at conception was linked to an increased risk of metabolic and cardiovascular diseases in the children during later life.
He said that this study has shown that being overweight at the time of conception appears to cause changes to the embryo at an early stage, which are more than likely related to the ovarian conditions in which the egg matured. These changes could reduce the chances of conception for women who are overweight and could result in long-term health implications for their children.
The study also found that the eggs of overweight or obese females are much smaller than those from females of a healthy weight, and are less likely to reach a very important development stage, named the ‘blastocyst’, which occurs around five days after fertilisation. They found that embryos from overweight and obese females reached this stage around 17 hours faster than those of healthy weight females.
The acceleration implied that fewer cells are formed in blastocysts which could result in a deleterious effect on the placenta.
The study discovered that embryos from overweight women offered a different biochemistry when compared to those from females of healthy weight. The embryos indicated altered amino acid metabolism.
The research involved the study of 368 fertilised eggs taken from 58 women whose weights ranged from healthy to overweight and obese, based on Body Mass Index (BMI) measurements. All these women were in the process of receiving fertility treatment at the Hull IVF Unit and the ‘spare’ embryos which were donated for this research were not harmed at all.
Dr Sturmey stated that the results of the study highlight the importance of maintaining a healthy pre-pregnancy weight, not only to boost the chances of conception, but also to ensure the good health of both mother and child.
Image Credit: Tony Alter