Cochrane Review: Restricted versus liberal water intake for preventing morbidity and mortality in preterm infants

Background Most premature infants are not sufficiently mature physiologically to ingest all of their required water and nutrients orally. Therefore, premature infants rely on their caregivers to regulate their volume of water intake. Thus, the caregiver must determine the amount of water to be given each day to such infants. Objectives To determine the effect of water intake on postnatal weight loss, the risks of dehydration, and other morbidities and mortality in premature infants. Search strategy Randomized clinical trials (RCTs) identified in previous versions of this review were re-examined and, in each case, retained. Additional trials were sought that compared the outcomes of interest in groups of premature infants who were given different levels of water intake according to experimental protocol. Such trials were sought in a list of trials provided by the Cochrane Neonatal Review Group, with a PubMed search, and in the authors' personal files. This search was updated in 2010. Selection criteria Only RCTs of varying water intake in premature infants are included. The review was limited to trials that included infants whose water intake was provided mainly or entirely by intravascular infusion. Data collection and analysis Standard methods of the Cochrane Collaboration were used. Study selection and data abstraction was performed independently by each reviewer. The adverse event rates were calculated for the restricted and liberal water intake groups for each dichotomous outcome, and the relative risk and risk difference were computed. In addition, the maximal weight loss results were recorded, and the weighted mean difference was computed. Main results The analysis of the five studies taken together indicates that restricted water intake significantly increases postnatal weight loss and significantly reduces the risks of patent ductus arteriosus and necrotizing enterocolitis. With restricted water intake, there are trends toward increased risk of dehydration and reduced risks of bronchopulmonary dysplasia, intracranial hemorrhage, and death, but these trends are not statistically significant. Authors' conclusions Based on this analysis, the most prudent prescription for water intake to premature infants would seem to be careful restriction of water intake so that physiological needs are met without allowing significant dehydration. This practice could be expected to decrease the risks of patent ductus arteriosus and necrotizing enterocolitis without significantly increasing the risk of adverse consequences. Plain Language Summary Restricted versus liberal water intake for preventing morbidity and mortality in preterm infants Most babies born before 37 weeks of pregnancy (preterm babies) are not developed enough to take all the water and nutrients they need by mouth. As a result, they are unable to regulate their intake of water. Inadequate water intake can cause the baby to become dehydrated. Excessive water intake can cause heart and lung problems or intestinal damage. Systematic review of trials related to this issue leads to the conclusion that careful restriction of water for preterm babies, to amounts that meets their physical needs without causing dehydration, reduces the risk of certain complications. More research on this topic is needed.