Postnatal Prediction of Gestational Age Using Newborn Fetal Hemoglobin Levels

INTRODUCTION In many parts of the developing world procurement of antenatal gestational age estimates is not possible, challenging provision of appropriate perinatal care. This study aimed to develop a model for postnatal gestational age estimation utilizing measures of the newborn hemoglobin levels and other metabolic analyte data derived from newborn blood spot samples. METHODS We conducted a retrospective cohort analysis of 159,215 infants born January 2012-December 2014 in Ontario, Canada. Multivariable linear and logistic regression analyses were used to evaluate the precision of developed models. RESULTS Models derived from a combination of hemoglobin ratios and birthweight were more precise at predicting gestational age (RMSE1·23weeks) than models limited to birthweight (RMSE1·34). Models including birthweight, hemoglobin, TSH and 17-OHP levels were able to accurately estimate gestational age to ±2weeks in 95·3% of the cohort and discriminate ≤34 versus >34 (c-statistic, 0·98). This model also performed well in small for gestational age infants (c-statistic, 0·998). DISCUSSION The development of a point-of-care mechanism to allow widespread implementation of postnatal gestational age prediction tools that make use of hemoglobin or non-mass spectromietry-derived metabolites could serve areas where antenatal gestational age dating is not routinely available.