Of the 73 mothers who completed the study, 59 (81%) of the mothers experienced vaginal births and 14 (19%) experienced Cesarean births; 36 were primiparous mothers and 37 multiparous mothers; 55 (75%) were primilactas, mothers who had not breastfed a previous infant. The infant sample consisted of 35 females and 38 males. Demographic data about mothers' ages, racial, ethnic, economic background, or marital status were not collected, as the study focused on the relationship between infant bowel output and infant weight rather than on possible influences of maternal demographic factors on the infants' bowel output or weight. All mothers in the study had private medical insurance. Infants in the study were older than or equal to 38 weeks gestation. Birth weights ranged from 5 lb 13 oz to 11 lb 4 oz with a mean of 7 lb 8 oz.
Feedings per day ranged from 6.2-11.4 with a mean of 8.5. Bowel movements per day ranged from 1.6-8.5 with a mean of 4.8. The first occurrence of yellow bowel movement ranged from 3-15 days, with 15 days meaning that the baby's bowel movements had not yet transitioned to yellow by the 14th day, the end of the study. The mean for transition to yellow bowel output was 6.8 days. Twenty infants (27.39 %) lost < 7% of birth weight. Forty infants (54.79 %) lost 7%-10% of birth weight. Thirteen infants (17.80%) lost > 10% (range 11%-14%). The mean day of regaining birth weight was 9.4, and 66% of infants had regained birth weight by 10 days of age. None of the infants in the study required hospitalization for dehydration or developed any health problems that required hospitalization. The sample is described in Table 3 .
Among the 73 infant subjects, those with the highest average of daily bowel movements during the first 14 days had the lowest initial weight loss and had the earliest transition to yellow bowel movements (see Table 4 for description). Those infants with the lowest number of average daily bowel movements had the highest percentage weight loss and the latest transition to yellow bowel movements. The first day of yellow bowel movement was a significant predictor (p < .007) of the percentage of weight lost, while the number of average daily bowel movements was a non-significant predictor of percentage of weight lost.
Among the infants who failed to regain birth weight by 14 days, the average number of daily bowel movements during the 14-day study period was 3.59 and the mean day of transition to yellow bowel movements was 9 days of age (see Table 5 ).
The correlation matrix of variables (see Table 6 ) demonstrates relationships pertinent to clinical practice. An increased number of bowel movements per 24 hours during the first 5 days following birth is significantly and positively related (r = .26, p < .05) to the infant's initial weight loss being less than 7% and the infant's percent of weight gain being higher at 14 days (r = .34, p < .001). The number of bowel movements per 24 hours during the first 5 days following birth is significantly and negatively associated (r = -.47, p < .001) with the day the bowel movements transition to yellow and with the likelihood that the baby will lose more than 10% of birth weight (r = -.26, p < .05). In summary, a greater number of daily bowel movements during the first 5 days following birth is associated with desirable outcomes for the infant, including initial weight loss less than 7% (r = .26, p < .05), earlier transition to yellow bowel movements (r = -.47, p < .001), earlier day of return to birth weight (r = -.42, p < .001), less likelihood of losing more than 10% of birth weight (r = -.26, p < .001), and heavier weight at 14 days (r = .34, p < .001).
A greater number of bowel movements per day during the entire 14-day study period was associated with earlier regaining of birth weight (r = -.26, p < .05) and a heavier weight at 14 days (r = .33, p < .005). Therefore, ample bowel output is associated with good infant weight gain. Other findings include the correlation between the baby having a day without any bowel movements and a later transition to yellow bowel movements (r = .28, p < .05). The day of transition to yellow bowel movements is negatively associated with maximum percentage weight gain (r = -.56, p < .001). Thus, early transition of stools is associated with a heavier infant weight at 14 days. Number of breastfeedings per day was not significantly related to initial weight loss, onset of weight gain, day of regaining birth weight, or weight at 14 days. All research study hypotheses were supported.
The following variables were entered hierarchically into a regression model to determine which would predict weight gain in a neonate: (a) number of breast feedings in 24 hours, (b) number of bowel movements per day during the first 5 days, (c) number of bowel movements per day during the 14 days of the study, and (d) day of first occurrence of yellow stool. The variables "number of breast feedings in 24 hours" and "number of bowel movements per day during the 14 days of the study" were non-significant. The variable "day of first occurrence of yellow stool" contributed 20.5% (p < .001) of the variance related to a neonate's weight gain, even after controlling for the number of times the infant was breast-fed and the number of bowel movements per day in the first 5 days and over the 14-day monitoring period. The statistical regression model, which included the variables "first day of yellow stool" and "number of bowel movements during the first 5 days," predicted 32.5% (p < .005) of the variation present in a neonate's weight and was significantly predictive of weight gain in an exclusively breastfed newborn infant.
Pediatr Nurs. 2006;32(3):195-201. © 2006 Jannetti Publications, Inc.
Cite this: The Neonatal Bowel Output Study: Indicators of Adequate Breast Milk Intake in Neonates - Medscape - May 01, 2006.