Intrapartum intravenous fluids for caesarean delivery and newborn weight loss: a retrospective cohort study

OBJECTIVE: To examine weight loss (WL) and excess weight loss (EWL) among newborns of caesarean delivery, comparing colloids plus crystalloids versus crystalloids only. Also, to examine different doses of intrapartum intravenous fluids on WL and EWL. DESIGN: Comparative safety retrospective cohort study. SETTING: University Teaching Hospital, Moncton, Canada. PATIENTS: Mothers exposed to intravenous fluids with caesarean delivery between 2008 and 2016. INTERVENTIONS: Exposure to colloids plus crystalloids was compared with crystalloids only, and dose-response analyses were performed for colloids, crystalloids and total intravenous fluids doses. Linear and logistic regression models were used, adjusting for potential confounders. MAIN OUTCOME MEASURES: Infants’ WL was measured at days 1, 2 and 3 post partum, and EWL defined as loss of >7% of birth weight. RESULTS: From 801 mother-infant pairs, 176 were exposed to colloids plus crystalloids and 625 were exposed to crystalloids only (overall mean birth weight=3416 g, EWL=2%, 41.4% and 55.5% on days 1, 2 and 3, respectively). No significant difference in newborns’ WL was observed on any of the days assessed. Adjusted OR (95% CI) of EWL was 1.0 (0.3 to 3.3) at 24 hours, 1.0 (0.7 to 1.5) at 48 hours and 1.4 (0.9 to 2.2) at 72 hours. No dose-response relationship was detected with type-specific and total intravenous fluids exposures. CONCLUSIONS: The risk of EWL was similar with colloids plus crystalloids and crystalloids only, suggesting that both therapeutic options can be considered during caesarean delivery. The absence of dose-response relationships adds confirmatory evidence to the intravenous fluids safety profiles.