First international growth standards for the developing baby could help combat stunting and obesity

New international standards for fetal growth and newborn size provide the first accurate measurements of ideal growth and development from conception to birth. Published in The Lancet, these new standards depict a healthy pattern of growth that is desirable for all fetuses and newborns everywhere, regardless of ethnic origin.

"Healthcare practitioners already have WHO international growth standards for children from birth up to the age of 5 that are used in 140 countries worldwide. Now they will have international standards for the developing fetus and newborn too", explained José Villar, lead author and Professor of Perinatal Medicine at the Nuffield Department of Obstetrics & Gynaecology, University of Oxford in the UK.*

"With these international standards, we will know when the nutrition and healthcare needs of the developing baby are not being met. Across the world, this will help identify signs of under-nutrition, stunting, wasting**, and overweight at an earlier stage to implement preventive actions to reduce long-term health problems, such as diabetes and hypertension."*

Currently, fetal growth and newborn size are evaluated around the world using over 100 different locally produced growth charts. They describe only how children grew in a particular population or region at a given time, rather than how a baby in the womb should grow when mothers have adequate health, nutrition, and socioeconomic status: the new international standards correct this situation.

Stephen Kennedy, one of the senior authors and Professor of Reproductive Medicine at the University of Oxford in the UK explained, "In one part of a city or country a fetus or newborn can be judged as small, but a healthy size in another. This can lead to inaccurate diagnosis and ultimately unnecessary, or a lack of appropriate, treatment."*

The INTERGROWTH-21st Project collected growth and size data, using the same equipment and methods, from eight diverse populations of babies born to 4607 healthy, well-nourished women in selected urban areas in Brazil, China, India, Italy, Kenya, Oman, the UK, and the USA. Women were selected based on an ideal environment for healthy growth, such as adequate nutrition, education, low environmental contaminants, and good healthcare.

To generate the first international standards for fetal growth, ultrasound scans were performed every 5 weeks from early pregnancy (14 weeks) to delivery to assess five growth measures - head circumference, biparietal diameter, occipitofrontal diameter, abdominal circumference, and femur length - using identical machines and measures in all countries.

In the second complementary study, new international centiles for weight, length, and head circumference for babies born between 33 and 42 weeks' gestation were obtained from more than 20 000 deliveries to healthy mothers selected using identical criteria as in the fetal growth study. The measurements were obtained within 12 hours of birth by centrally trained teams using identical equipment in all countries.

According to Professor Villar, "These new standards allow, for the first time, international comparisons of newborn size from 33 to 42 weeks' gestation, complementing the existing WHO Child Growth Standards, which start at birth but do not differentiate according to gestational age. From now on, international standards can be used worldwide to make judgements on growth and size from conception to 5 years."*

Commenting on the research, Ola Didrik Saugstad, Professor of Paediatrics at the University of Oslo in Norway calls for the new growth charts to be endorsed by the international community. He writes, "These newborn growth charts are essential to guide clinical practice and could become a basic way to promote global child health...The charts show that previously recorded geographical differences in fetal growth are caused mainly by different environments. These growth charts could become a valuable method to identify non-optimum conditions for the newborn infant. Surveillance of a child's somatic growth against a reference standard can assess child health and development. Deviation from the standard should be identified quickly to detect stunting, which might also be related to adult disease. The new international standards are also more appropriate for early detection of overweight at birth and hence might contribute to earlier prevention of obesity worldwide."