4.3 Limitations
The main limitation of this study was inadequate documentation of maternal fluid balance. This limitation has been encountered by other researchers investigating intrapartum IV fluids practices. (11, 31, 32) In our study inadequate documentation necessitated the exclusion of certain cases and the assumption of consistent IV fluids administration rates continued between bags. Whilst this approached helped to mitigate selection bias and uphold the study’s internal validity, there remains the potential that non-differential misclassification of IV fluids volume occurred. Moreover, the necessity to categorise IV fluids intake into two groups may have diluted our findings and increased the risk of a Type 2 error (failing to reject a false null hypothesis).
A second limitation of this study was the visual estimation of maternal blood loss. Maternal blood loss at birth can be underestimated when visual estimation is used.(7, 33) Consequently, maternal blood loss may have been systematically underestimated, particularly given the infrequent documentation of cumulative blood loss within the initial 24 hours postpartum.