The Neonatal Bowel Output Study: Indicators of Adequate Breast Milk Intake in Neonates

Linda C. Shrago; Elizabeth Reifsnider; Kathleen Insel


Pediatr Nurs. 2006;32(3):195-201. 

In This Article


The study was conducted at the Family Birth Place at Mercy Health Center, Oklahoma City, Oklahoma, during the 12-month period from August 1995 to August 1996. The study protocol and an informed consent form were approved by the Institutional Review Board at Mercy Health Center.

A convenience sample was recruited from among individuals who met inclusion criteria, which were the following: (a) inpatients of the Family Birth Place; (b) ability to read and understand English; (c) hearing sufficient to comprehend verbal instructions; (d) lived within driving distance of the health center, for ease in returning the scale; (e) had a telephone, for ease in contacting them to encourage return of the scale; (f) had not experienced blood loss in excess of 2500 ml; and (g) did not plan to give formula to their infant during the study period. Inclusion criteria for infants were: (a) singletons, (b) not less than 38 weeks gestation, (c) weighed not less than 2500 grams, (d) had no congenital defects or neurological injuries documented in the medical record, and (e) were healthy enough to be discharged from the hospital with their mothers.

At the conclusion of the study, mothers completed a questionnaire that provided information about whether the infant should be excluded from the study because he or she had met exclusion criteria. Infants were excluded at the end of the study if (a) the infant had received phototherapy or antibiotics during the study period, as these can increase the frequency of stools and can affect the color of stools, or (b) the infant received treatment from a physician for an illness, as illness could influence the infant's ability to feed, or (c) the mother had taken laxatives, as some formulations can increase the frequency of the infant's stools (Hagemann, 1998), or (d) the infant had received infant formula, as infant formula can influence the frequency and color of bowel movements. Receiving infant formula also meant that the infant was not exclusively breastfed. An infant who received water or glucose water or expressed breast milk was not excluded from the study. One hundred thirty one subjects were enrolled in the study; 58 subjects were excluded at the end of the study due to meeting exclusion criteria or due to incomplete record keeping; 73 subjects completed the study. Table 2 summarizes reasons infants were excluded from the study at its conclusion.

Breastfeeding was defined as an occurrence of the infant taking breast tissue into his or her mouth, sucking, and swallowing for a period of at least 3 minutes. If the second breast was taken within 30 minutes of the first breast, it was considered one breastfeeding. If more than 30 minutes elapsed between the first and second breast, it was considered a separate breastfeeding. Breast milk could be given directly or indirectly. A bowel movement was recorded only if the amount was judged by the mother to be as large as, or larger than, a quarter (American coin), which is 2.5 cm in diameter.

The term "maximum percentage weight gain" was used to mean "percent of birth weight at 14 days." A baby who is back to birth weight is at 100% of birth weight. A baby who has exceeded birth weight has a weight that is greater than 100%. A baby who is under birth weight has a weight that is less than 100% of birth weight.

The infant intake/output/weight log was a pre-printed form on which mother recorded each of the infant's breastfeedings from birth through and including the entire 14th day following birth. The mother recorded on the log every bowel movement during the study period, recording the stool color based on a color chart that was provided. At approximately the same time each day during the study period, the mother weighed the infant naked and recorded the weight on the log.

The scale used in the study was an electronic infant scale, brand name BabyWeigh, manufactured and distributed by Medela, Inc., McHenry, IL. This scale weighs to the nearest 2 grams and is designed for home use. Accuracy of this scale was investigated by Meier and colleagues (1994) and was found to be comparable to the Smart Model 20 (Olympic Medical, Seattle, Washington, USA), whose accuracy had been previously documented (Meier, Lysakowski, Engstrom, Kavanaugh, & Mangurten, 1990). Mothers were given verbal instructions, written instructions, and a demonstration of how to weigh the infant on the research scale. Mothers performed a return demonstration of the weighing technique.


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