The Foetal Hypothesis – Our health starts in the womb

Is chronic illness pre-determined from our time in the womb? If so, can we reverse any harmful effects, to improve our health and longevity later on? 

Professor David Barker was an eminent scientist, who established the 'Fetal Origins Hypothesis’ in 1995. Is it still valid and relevant today? 

What was his theory? 

Professor Barker researched the long term health effects of low birth weight in a range of different countries. He concluded that lower birth weight (and/or possibly a smaller surface area of the placenta) typically led to a higher incidence of adult chronic disease. This included cardiovascular disease (heart attack and stroke), cancer and type-2 diabetes. 

  • He proposed that there is a hierarchy of priorities in the womb. The brain has top priority and those organs that do not function in the womb, like the kidneys and lungs, have the lowest priority. So if the foetus is receiving insufficient nutrition, the low priority organs will receive less nutrition, leaving them weaker and more vulnerable. This means crucial genes are not being switched on, as they should during foetal development. This results in permanent change to the structure and function of the unborn baby, which will affect it for the rest of its life. 
  • His research suggested that the main long term health risks were for babies who were small because they grew slowly, rather than for premature babies. However, more recent research suggests that being born prematurely modestly increases the risk of diabetes in later life.    

Other studies have continued to show that health in the womb and low birth weight appear to be related to future chronic illnesses – including as recently as 2011.  

Is this relevant to me? 

  • 7% of babies born in the UK in 2009 had a low birth weight (less than 2,500g/5 pounds 8 ounces after 37 weeks of pregnancy).
  • That means the vast majority of births in the UK were notunderweight. So, while Barker’s hypothesis maybe true, most of us need to address other factors to ensure a long and healthy life.
  • However, 7% of a UK population of 63 million people is still a sizeable number. Over 4 million people are potentially affected. 

Can we prevent low birth weight? 

One factor mothers-to-be can influence is eating a balanced and varied diet. This appears to increase the chances of healthy birth weight babies, whatever your background. 

What can you do if you are born with a low birth weight? 

If you are born with a low birth weight, regular moderate exercise may help reduce the health risks associated with the condition. 

One European study didn’t find that exercise helped compensate for low birthweight in healthy children and adolescents.

However, it noted that higher levels of physical activity are beneficial for metabolic risk - reducing the risk of heart disease, stroke or diabetes throughout life. It also noted that the compensating effect on birth weight may only become apparent later in adult life or for people at greater metabolic risk. 

How reliable is the Barker hypothesis? 

The Hypothesis is well respected in the scientific world and continues to be a useful tool when considering what may affect a person later in life. However, it should probably be considered alongside other factors, as part of the broader life course i.e. what happens after birth as well as what happens before birth.

So how much of our adult health and longevity are we responsible for? 

  • Around 7% of the UK population (i.e. around 4 million people) are potentially affected by Barker’s theory, as they have a low birth weight.
  • We remain responsible for ensuring we exercise, eat well and maintain a healthy lifestyle. This should reduce the risk of developing chronic illness, whatever our birthweight.

Conclusion 

  • There appears to be an association between low birth weight and increased risk of type-2 diabetes and coronary heart disease in adult life. 
  • Lower socio economic status had been seen as increasing the risk of low birth weight and remains a risk in the developing world.
  • Currently, in the UK, being a single parent appears to be a more significant factor.
  • Improving the nutrition of girls and young women is likely to prove beneficial. 
  • We need to eat a balanced and varied diet and to take regular, moderate exercise. Whatever our birth weight, this increases the chances of ourselves (and our children) having healthy lives and living longer.

Emma Juhasz

Reviewed 23 July 2014, next review date November 2018