Prevalence of small-for-gestational-age and its mortality risk varies by choice of birth-weight-for-gestation reference population

• Published in: PloS one 2014-03, Vol.9 (3), p.e92074-e92074
• Main Authors: Katz, Joanne, Wu, Lauren A, Mullany, Luke C, Coles, Christian L, Lee, Anne C C, Kozuki, Naoko, Tielsch, James M
• Format: Article
• Language: English
• Subjects: Age; Biology and Life Sciences; Birth; Birth Weight; Childbirth & labor; Childrens health; Female; Females; Gestation; Gestational Age; Health aspects; Humans; Income; India - epidemiology; Infant; Infant mortality; Infant Mortality - ethnology; Infant, Newborn; Infant, Premature; Infant, Small for Gestational Age; Infants; Intensive farming; Low income groups; Male; Males; Medicine and Health Sciences; Mortality; Neonates; Nepal - epidemiology; Newborn babies; Newborn infants; Physical Sciences; Population; Population studies; Populations; Pregnancy; Prenatal development; Prevalence; Public health; Reference Values; Research and Analysis Methods; Risk; Rural Population; Sex Factors; Small-for-gestational age; Womens health
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0092074

We use data from rural Nepal and South India to compare the prevalence of small-for-gestational-age (SGA) and neonatal mortality risk associated with SGA using different birth-weight-for-gestation reference populations. We identified 46 reference populations in low-, middle-, and high-income countries, of which 26 met the inclusion criteria of being commonly cited and having numeric 10th percentile cut points published. Those reference populations were then applied to populations from two community-based studies to determine SGA prevalence and its relative risk of neonatal mortality. The prevalence of SGA ranged from 10.5% to 72.5% in Nepal, and 12.0% to 78.4% in India, depending on the reference population. Females had higher rates of SGA than males using reference populations that were not sex specific. SGA prevalence was lowest when using reference populations from low-income countries. Infants who were both preterm and SGA had much higher mortality risk than those who were term and appropriate-for-gestational-age. Risk ratios for those who are both preterm and SGA ranged from 7.34-17.98 in Nepal and 5.29-11.98 in India, depending on the reference population. These results demonstrate the value of a common birth-weight-for-gestation reference population that will facilitate comparisons of SGA prevalence and mortality risk across research studies.