In a 2013 study published by the American Journal of Obstetrics and Gynecology, lead author Dr. Gillian Hanley, a post-doctoral fellow with UBC’s School of Population and Public Health (SPPH) and the Child & Family Research Institute (CFRI), states that “When we expect Chinese, South Asian and Caucasian babies to be the same size at birth, we risk misclassifying small but healthy Chinese and South Asian babies as small for gestational age.

Small for gestational age (SGA) classification is associated with higher risk of hypothermia, hypoglycemia and infection, and likely to lead to admission to the neonatal intensive care unit.

Dr. Hanley and Dr. Patricia Janssen, an SPPH professor and CFRI scientist, examined data from more than 100,000 newborns in Washington state against two birth-weight standards:

1. A population-based birth weight chart used by most hospitals
2. A birth weight chart that accounts for the ethnicity of infants.

Their findings show that a considerable number of babies, classified as small for gestational age by the conventional birth weight chart, were actually healthy babies. The study findings showed that newborns considered SGA by ethnicity-specific weight distributions were significantly more accurate in determining risk and need for intervention (Apgar score less than 7 at 5 minutes, admission to the neonatal intensive care unit, ventilation, extended length of stay in hospital, hypoglycemia, hypothermia and infection). “In contrast, newborns considered SGA by population-based birth weight distributions alone were at no higher risk of any adverse outcome except hypothermia and neonatal intensive care unit admission.”

The study demonstrates that using standard weight charts to determine infant risk factors can lead to healthy babies receiving medical intervention they don’t really need, and to increased parental anxiety, unnecessary testing and increased health care costs. The study outcomes indicate that developing and implementing ethnicity-based standards can assist in directing attention to babies who need it most.