How diet and lifestyle affects your baby's outcome

By Annemarie Aburrow RD

This article provides a summary of the BNF Task Force Report entitled “Nutrition and development: short- and long-term consequences for health", which was published in May 2013.

Most mums-to-be know that a healthy diet and lifestyle in pregnancy will improve the health of their baby. But just how much of an effect do our diets have on the baby? A successful pregnancy involves many complicated processes happening at the correct time. There are periods during pregnancy where the baby is particularly vulnerable. Poor growth and development during these periods may lead to chronic diseases in later life. We need the right nutrition to make the most of these 'windows of opportunity' in the baby's growth and development.

Pre-conception diet is really important in the baby's development. The organs begin to take shape around week 6 of pregnancy, when many women have only just realised they're pregnant. This 'window of opportunity' may be missed unless good nutrition and lifestyle habits have been establish beforehand.

Research suggests that not only mum-to-be's pregnancy and pre-pregnancy diet and lifestyle affects the baby's outcome, but also her mother's diet (baby's maternal grandmother). Amazingly, the environment in which the baby develops in the womb has a greater influence on growth than genetics itself. The ability of the placenta to transfer the right nutrients to the baby is 'programmed' by this inter-generational affect.

Why birth weight is important

Your baby's birth weight can determine their future health. The average birth weight of babies born in the UK is 3.4kg (7lb 8oz). Babies are classed as 'low birth-weight' if they're born under 2.5kg. High birth-weight babies weigh more than 4kg. Both low and high birth-weight babies are more likely to develop health conditions like heart disease, diabetes and osteoporosis in later life. This is usually because they have not received optimum nutrition during pregnancy (they have been exposed to too much or too little nutrition).

How poor nutrition in pregnancy affects baby's outcome

Babies born to obese mums

The number of overweight and obese mothers has significantly increased over the last 10 years, which has a direct affect on birth-weight. Obese mums-to-be have higher blood sugar levels, meaning their babies have higher birth weights and are more likely to become obese later on. Babies born to obese mums are more likely to become obese themselves in childhood and adulthood.

Increases obesity in later life

When a baby faces inadequate nutrition, it channels nutrients to its vital organs (heart, brain, adrenal glands and placenta), and other organs (e.g. bones, pancreas, muscles and lungs) suffer. Low birth-weight babies are more likely to become obese when they have periods of plentiful nutrition later in childhood and adulthood.

Low birth-weight is also related to higher adult blood pressure and therefore a higher risk of heart disease. Babies born small for gestational age who rapidly gain weight in the first 6-12 months of life ('catch up growth') are likely to develop increased body fat in later life, increasing obesity risk. Increasing weight at a slower rate in these babies would be beneficial.

Increases risk of diabetes

If organs including the pancreas have received poor nutrition during development in the womb, they don't develop properly. The pancreas makes insulin, the hormone responsible for controlling blood sugar levels by enabling cells to convert sugar to energy. If the pancreas hasn't developed properly, it may produce less insulin, increasing risk of diabetes. Being overweight or obese in later life also increases risk of diabetes.

Increases risk of heart disease

Babies born with low or high birth weights are at increased risk of heart disease. The risk is much greater for babies that become overweight or obese in later life.

Link with cancer

Studies have found higher risk of breast cancer in babies born with high birth weights. A healthy pre-conception diet may help reduce the risk of her baby developing cancer.

Development of healthy gut bacteria

Our guts contain colonies of healthy bacteria, which help to stop harmful bacteria from growing, help with the absorption of certain nutrients and are beneficial for the immune system. Gut bacteria become established through the birth process, milk feeding and then weaning, and stabilise around the age of 2. Low birth-weight babies or babies born premature have lower numbers and less variety of bacteria in their guts. Links have been found between certain bacteria varieties and development of autism, ulcerative colitis, Crohn's disease and colorectal cancer.


If a mother does not have enough energy (calories), protein, micronutrients and essential fatty acids (e.g. omega-3), the development and function of her baby's brain can be affected. It babies are born small or large for gestational age or are born prematurely, this may affect baby's brain structure and development and therefore IQ.

What can you do to improve your baby's outcome?

Before pregnancy:

During pregnancy:

Post-pregnancy & into the future:

You might also like:

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Weight gain during pregnancy

Your guide to first trimester nutrition

Your guide to second trimester nutrition

Your guide to third trimester nutrition

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Healthy nutrition tips for the vegetarian mothers-to-be


Your New Pregnancy Bible

The experts' guide to pregnancy and early parenthood - by Dr Anne Deans


Your guide to second trimester nutrition

Your guide to third trimester nutrition

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Caffeine in pregnancy: How much is too much?

“Pass the sick bag”: Eating your way through Hyperemesis Gravidarum

The role of probiotics in breastfeeding

Digestive problems during pregnancy

Calcium during pregnancy – what you need to know

Your guide to first trimester nutrition

Trying to Conceive? Foods you should avoid

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