In this study with prospective neurodevelopmental assessment of children who experienced neonatal dehydration, we found little evidence of adverse effects. Although our results cannot be generalized to catastrophic dehydration, they do provide reassurance that the more common possible adverse effects of dehydration, such as mild cognitive, behavioral, or motor impairment, are unlikely to occur in the type of dehydration usually seen by primary care physicians.
Because dehydrated newborns tend to be hypernatremic(1
) the pathophysiology relevant to neonatal dehydration relates to hypernatremic states and to problems resulting from the intravenous fluid correction of such states.(7
) If dehydration persists long enough, the adverse effects are similar to those mediated by acidosis and hypovolemic shock(34
). However, we did not find any significant differences between cases and controls. We did not find such differences even when restricting the comparisons to the group of newborns with the greatest degree of dehydration.
Important limitations of our study must be noted. First, it is possible that favorable parent-infant interactions might be masking deficits due to the adverse effects of dehydration. Second, none of our study subjects had shock, respiratory failure, infarcts, or gangrene during their dehydration episode. Thus, our findings apply to cases of neonatal dehydration that is detected before these catastrophic events and cannot be generalized to cases of severe dehydration that have end organ damage. Third, we had a higher participation rate among dehydrated subjects than among controls. This is not surprising, because the research questions for the study were inherently les s interesting for parents of the control children. If children in the participant control group were at higher risk of bad outcome than the control group as a whole, this could introduce a bias that would make the outcome among participating controls appear worse than it would have been with a more representative sample, and thus make the outcomes in the dehydration group look better in comparison. Based upon data from perinatal medical records and birth certificates, we have little evidence that this occurred. It is also reassuring that means on standardized tests in the dehydration group were uniformly and solidly average compared to national norms. Fourth, 5 years is still a young age. If non-catastrophic dehydration has subtle effects on higher cortical function, which would be manifested in difficulties with more complex tasks, assessment at 5 years might be too early to detect such effects.
Findings from our study may not be generalizable to different populations in developed nations. Our sample came from an insured population with a fairly high education level as well as a high rate of breastfeeding. These families had ready access to a number of support services (follow-up clinics and phone advice banks staffed by registered nurses) and no barriers to prompt rehospitalization.
In conclusion, our findings support current American Academy of Pediatrics recommendations for the follow-up of newborns, which specify the need to assess newborn hydration.(35
) They also suggest that parents of infants who experienced rehospitalization for dehydration in the newborn period can be reassured that the episode is unlikely to have had significant adverse neurological effects.