Maternal body height is a stronger predictor of birth weight than ethnicity: analysis of birth weight percentile charts.

BACKGROUND: Anthropometric parameters such as birth weight (BW) and adult body height vary between ethnic groups. Ethnic-specific percentile charts are currently being used for the assessment of newborns. However, due to globalization and interethnic families, it is unclear which charts should be used. A correlation between a mother's height and her child's BW (1 cm accounts for a 17 g increase in BW) has been observed. The study aims to test differences in small for gestational age (SGA) and large for gestational age (LGA) rates, employing BW percentile charts based on maternal height between ethnic groups.

METHODS: This retrospective study of 2.3 million mother/newborn pairs analyzed BW, gestational age, sex, maternal height and ethnicity from the German perinatal survey (1995-2000). These data were stratified for maternal height (≤157, 158-163, 164-169, 170-175, ≥176 cm) and region of origin (Germany, Central and Northern Europe, North America, Mediterranean region, Eastern Europe, Middle East and North Africa, and Asia excluding Middle East). Percentile charts were calculated for each maternal height group.

RESULTS: The average BW and maternal height differ significantly between ethnic groups. On current percentile charts, newborns of taller mothers (≥176 cm) have a low rate of SGA and a high rate of LGA, whereas newborns of shorter mothers (≤157 cm) have a high rate of SGA and a low rate of LGA. When the BW data are stratified based on the maternal height, mothers of similar height from different ethnic groups show similar average BWs, SGA and LGA rates.

CONCLUSION: Maternal body height has a greater influence on BW than maternal ethnicity. The use of BW percentile charts for maternal height should be considered.