Maternal hemoglobin concentration and its association with birth weight in newborns of mothers with preeclampsia

Abstract

Objective. Maternal hemoglobin concentration is inversely related to newborn size presumably through plasma volume constriction. We sought to determine whether birth weight would show an inverse relationship to hemoglobin concentration in a group of infants whose mothers had preeclampsia, where plasma volume constriction is common.Methods. Electronic and paper chart review identified 142 nulliparous women with preeclampsia (excluding hemolysis, elevated liver enzymes, low platelets syndrome). Birth weight percentile was determined based on cross-sectional hybrid growth curves. Maximal third trimester maternal hemoglobin concentrations were obtained and standardised to z-scores based on gestational age matched normative data. Birth weight percentile was examined as a function of hemoglobin z-score using appropriate statistics.Results. Average gestational age at delivery was 35.9 ± 1.9 weeks. Mean birth weight percentile for infants of preeclamptic mothers was 34 ± 32. Mean hemoglobin z-score for mothers with preeclampsia was 0.3 ± 1.5, significantly higher than a control population (p = 0.04). Maternal hemoglobin z-score was inversely associated with birth weight percentile (r = −0.18, p = 0.03).Conclusion. Maternal hemoglobin concentrations are significantly elevated prior to delivery in women with preeclampsia. There is a statistically significant inverse correlation of maternal hemoglobin concentration to birth weight percentile.