Neonatal weight measurements are used as a key indicator of breastfeeding adequacy. The purpose of this study was to explore non-feeding factors that might be related to newborn weight loss. The relationship between the intravenous (IV) fluids women receive during parturition (the act of giving birth including time in labour or prior to a cesarean section) and their newborn's weight loss during the first 72 hours postpartum was the primary interest.
Three hypotheses guided the thesis. Specifically, the hypotheses stated that in the first 72 hours postpartum, there is a positive association between: (a) the amount of IV fluid given to a woman during parturition and the amount of weight her infant loses; (b) the amount of IV fluid given to a woman during parturition and the amount her infant eliminates; and (c) the amount an infant eliminates and the infant's weight loss.
In an effort to clarify patterns of weight loss, a systematic review was completed to determine reference weight loss, and the results are reported in this thesis. Additionally, the issue of who should consent for neonates in lactation and breastfeeding research studies was raised during the ethics review, and the results of an examination of the underpinning principles for such consent are presented in this thesis.
A prospective observational cohort study was conducted to explore associations between maternal fluids during parturition, neonatal output, and newborn weight loss. During labour or before a cesarean section, maternal IV and oral fluids were recorded. Participants weighed their newborns every 12 hours for 72 hours, then weight was measured daily from Day 4 to Day 14. Parents weighed all output (i.e. diapers) in the first 72 hours.
Results of the systematic review show that the 7% maximum allowable weight loss recommended in four clinical practice guidelines appears to be based on mean weight loss and does not account for standard deviation. Although we determined patterns of weight loss, causes of weight loss and implications for morbidity and mortality were not established. Completing the systematic review clarified assumptions about how birth weight is used as the baseline for calculating weight loss and how clinical decisions are based on the percentage of loss from birth weight.
The three hypotheses were supported. At 60 hours postpartum (point of maximum weight loss), mean loss was 237.2 grams (SD 98; n = 96, range 70-467 grams) and the percentage lost was 6.57 (SD 2.51; n = 96, range 1.83-13.06%). There was a positive relationship between maternal IV fluids from admission to birth and neonatal weight loss in grams (r(83) = .199, p = .035). Mean neonatal output for the first 24 hours was 83.04 grams (SD 47.81; n = 107, range 0-314 grams). There was a positive relationship between maternal IV fluids given in the final 2 hours before birth and neonatal output at 24 hours (r(17) = .426, p = .044) which explained 18% of the variability in weight loss. On Day 1, there was a positive relationship between output and weight loss (r(96) = .341, P < .0001) which explained 12% of the variability in weight loss. When groups, based on maternal fluids, were compared (≤1200 mls [n = 21] versus> 1200 [n =53]), newborns lost 5.51% versus 6.93% (p = 0.03). A hierarchical regression analysis indicated gestational age and birth weight were additional predictors of weight loss. It appears neonates experience diuresis in the first 24 hours with a related weight loss.
Overall, the results indicate that maternal IV fluids before birth are related to weight loss in the early postpartum period. It appears neonate's experience varying degrees of diuresis, and consequent weight loss, in the first 24 hours is a correction. Clinicians (e.g. nurses, lactation consultants, and physicians working with breastfeeding women) should reconsider using birth weight as baseline when assessing newborn weight loss. These findings support using weight measured at 24 hours postpartum as the baseline for assessing newborn weight loss.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/30114 |
| Date | January 2011 |
| Creators | Noel-Weiss, Joy |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 173 p. |
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