Key content

• There are currently more than 100 different population-based and customised charts in use, hence definitions of small-for-gestational-age (SGA) are inconsistent.
• Over 130 countries have adopted the World Health Organization Child Growth Standards. These standards recognise that all children can achieve similar growth if environment, nutrition and health are optimal.
• The INTERGROWTH-21st Project was a large-scale, multicountry study that measured fetal growth of babies in utero and at birth in mothers in whom environmental, social, medical and pregnancy conditions were optimal.
• International standards for fetal measurement and the assessment of newborn size at birth will enable continuity of measurement from the pregnancy to childhood.

Learning objectives

• Understand that 97% of variation in fetal growth is caused by factors unrelated to ethnicity.
• When conditions for growth are optimal, fetal growth is strikingly similar around the world.

Ethical issues

• Consider poor fetal growth as a human rights issue: what is the legacy for individuals and societies where undernutrition has occurred in the first 1000 days of life?
• Recognise that, as obstetricians, we have a duty to help the most disadvantaged. The practice of ‘customising’ for ethnicity could normalise suboptimal growth.

The Obstetrician & Gynaecologist: Hirst, JE, Papageorghiou, AT, for the International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st). INTERGROWTH-21st: a new paradigm for fetal growth in the 21st century. The Obstetrician & Gynaecologist 2016; 18: 137– 141.