Birthweight charts customised for maternal height optimises the classification of small and large‐for‐gestational age newborns

Abstract

AbstractAimTo construct birthweight charts customised for maternal height and evaluate the effect of customization on SGA and LGA classification.MethodsData were extracted (n = 21 350) from the MiCaS project in the Netherlands (2012–2020). We constructed the MiCaS‐birthweight chart customised for maternal height using Hadlock's method. We defined seven 5‐centimetre height categories from 153 to 157 cm until 183–187 cm and calculated SGA and LGA prevalences for each category, using MiCaS and current Dutch birthweight charts.ResultsThe MiCaS‐chart showed substantially higher birthweight values between identical percentiles with increasing maternal height. In the Dutch birthweight chart, not customised for maternal height, the prevalence of SGA (<p10) decreased with increasing maternal height category, from 19.7% in the lowest height category to 3.4% in the highest category (range 16.3%). Conversely, the prevalence of LGA (>p90) increased with increasing height category, from 1.4% in the lowest height category to 21.8% in the highest category (range 20.4%). In the MiCaS‐birthweight chart, SGA and LGA prevalences were more constant across maternal heights, similar to overall prevalences (SGA range 3.3% and LGA range 1.7%).ConclusionCompared to the current Dutch birthweight chart, the MiCaS‐birthweight chart customised for maternal height shows a more even distribution of SGA and LGA prevalences across maternal heights.