Birth-weight charts and immigrant populations: A critical review

- Differences in birth weight (BW), low birth weight (LBW), and small for gestational age (SGA) between minority groups are difficult to interpret.
- Misclassification of abnormal newborn size may lead to unnecessary intervention or conversely, overlooking babies requiring special care.
- Newborn size charts should be used as screening tools, not as diagnostic tools.
- Local population-based BW references, including minority-specific charts, are appropriate for research but not for clinical practice.

There is an increasing body of literature focusing on differences in newborn size between different population subgroups defined by racial, ethnic, and immigration status. The interpretation of these differences as pathological or as merely reflecting normal variability is not straightforward and may have consequences for the provision of obstetric and neonatal care to minority populations. In this review, we critically assess some methodological issues affecting the assessment of newborn size and their potential implications for minority populations. In particular, we discuss the pros and cons of different types of newborn birth-weight (BW) charts (i.e., single local population-based references, minority-specific references, and a single international standard) to determine abnormal newborn size, with emphasis on immigrant populations. We conclude that size alone is not enough to inform clinical decisions and that all newborn size charts should be used as screening tools, not as diagnostic tools. Parental minority status may be regarded as a marker and used to further inquire about individual risk factors, particularly among immigrants who may not have a complete medical history in the new country. Finally, we outline areas for further research and recommendations for clinical practice.