Babies the world over are strikingly similar in size if they are born to healthy, well-educated mothers, a new study has found.

It looked at almost 60,000 pregnancies in eight countries, including the UK, the US, Brazil, China and Kenya.

Currently, there are wide disparities in the average size of babies born worldwide. The size of a baby can have long-term consequences for their health. For example, babies who are small for their gestational age may have problems at birth such as breathing difficulties and hypoglycaemia (low blood sugar), but they also have an increased risk of developing conditions as adults, such as diabetes and heart disease.

Meanwhile increasing rates of obesity are also resulting in more large babies being born. Larger babies can be more difficult to deliver.

Previous studies have suggested that race and ethnicity may play a role in the size of babies born in different places. However, these latest results indicate that what matters more is the health, nutritional status and education of the mother, along with the level of care provided during the pregnancy.

The researchers measured the bone growth of the babies using ultrasound scans throughout the pregnancy. Each baby's length and head circumference were also measured when they were born.

The study found that irrespective of where a child is born, they are likely to be the same size if their mother is healthy, well-nourished and well-educated. In fact, their measurements - bone growth, length and head circumference - are described as ‘strikingly similar' throughout the world.

The researchers believe they have demonstrated that if a mother's health, nutrition, education status and care during pregnancy are all equally good, their babies will have an equal chance of healthy growth.

"Currently we are not all equal at birth. But we can be. We can create a similar start for all by making sure mothers are well educated and nourished, by treating infection and by providing adequate antenatal care. Don't say that women in some parts of the world have small children because they are predestined to do so. It's simply not true," insisted the study's lead author, Prof Jose Villar, of the University of Oxford.

Meanwhile, also commenting on the results, Prof Zulfiqar Bhutta of the Aga Khan University in Pakistan, who is chairperson of the steering committee of this global research team, insisted that ‘the fact that when mothers are in good health, babies grow in the womb in very similar ways the world over is a tremendously positive message of hope for all women and their families'.

"But there is a challenge as well. There are implications in terms of the way we think about public health. This is about the health and life chances of future citizens everywhere on the planet. All those who are responsible for healthcare will have to think about providing the best possible maternal and child health," he added.

Details of these findings are published in the journal, The Lancet, Diabetes & Endocrinology.

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