Nutritionist Wendy Oddy likens growing babies to nurturing a small plant – if they’re not given the right nourishment right from the start they never really recover.

Dr Oddy, an associate professor and researcher at the Telethon Institute for Child Health Research, says there are compelling reasons for mums-to-be to drop the junk food and soft drinks and focus on good, healthy eating during pregnancy.

Apart from preventing optimal brain development in the baby, inadequate nutrient intake can retard the growth of the placenta, and may increase the risk of miscarriage and premature birth, with low birth weight. Babies with low birth weight are more vulnerable at birth and continue to be so throughout life.

“A well-nourished mother will produce a good-sized, healthy baby and if the baby’s a good size, it will be more active, it will be more mentally alert, will have less colic, diarrhoea, anaemia and infections,” Dr Oddy says.

Mums also need to beware of “eating for two”. they need increase their calorie intake by only 300-500 calories a day – the equivalent of a cheese and tomato sandwich on wholemeal or a little tub of yoghurt – and should avoid empty foods such as takeaways, lollies, chocolates and soft drinks. Excessive weight gain or existing obesity can put them at risk of high blood pressure and gestational diabetes and put the baby at risk of obesity and diabetes in later life.

“Go for nutrient-dense foods rather than just kilojoules – solid, heavy wholemeal breads and cereals, lots of vegetables and fresh fruit, legumes, fish, chicken and low-fat dairy,” Dr Oddy says.

Pregnant women also need to up their folate intake before and early in pregnancy to prevent neural tube defects, and maintain a good intake of iron, calcium and omega-3 fatty acids. Omega-3 fatty acids, also available in breast milk, are vital for brain development and the lack of them has been associated with depression.

“Looking after your health during pregnancy by having a nutritious diet is the most important thing, because if the mother isn’t well or not having a healthy diet that will affect the baby,” Dr Oddy says. “She might have more anaemia, pre-eclampsia, she might have more fatigue and mood swings, and morning sickness and cramps and other complaints. but if the nutrition is at optimum that will help keep away those negative symptoms of pregnancy.”