Using 24-Hour Weight as Reference for Weight Loss Calculation Reduces Supplementation and Promotes Exclusive Breastfeeding in Infants Born by Cesarean Section

Abstract

Background and Objectives:

To promote exclusive breastfeeding, supplements are not recommended without medical indications such as clinical evidence of dehydration. Loss of ≥10% of birth weight (BW) often triggers supplementation due to nursery staff's concern for dehydration. Studies have demonstrated that transplacental passage of maternal intrapartum intravenous fluids for anesthesia may inflate BW. Researchers have proposed using newborn's 24-hour weight (24HW), after fluid diuresis, as preferred reference for weight loss calculation. The mother–infant unit at Hartford Hospital, a Baby-Friendly Hospital, implemented this recommendation into routine practice in March 2014. This study was conducted to evaluate this practice change's safety and effectiveness in decreasing supplementation.

Methods:

We performed a retrospective chart review on healthy full-term newborns delivered by C-section in 12 months before (n = 404) and a 12-month period after (n = 263) incorporating the 24HW into routine practice. Overall supplementation rate, maximum weight loss, length of stay (LoS), and peak transcutaneous bilirubin (TcB) were compared.

Results:

Overall supplementation rate decreased from 43.6% pre- to 27.4% postintervention and in first-time mothers from 51.9% to 31.0%. Among infants losing ≥10% of BW, the supplementation rate decreased from 63.9% to 26.2%. There was no significant increase in maximum weight loss, peak TcB level, or LoS overall or in those with ≥10% weight loss from birth.

Conclusion:

Routine use of 24HW as the reference for newborn weight loss calculation reduced supplementation and did not increase untoward effects during the hospital stay.

Introduction

In the policy statement, Breastfeeding and the Use of Human Milk, the American Academy of Pediatrics (AAP)¹ summarized the positive infant and maternal outcomes from exclusive breastfeeding. Introducing supplementations in the nursery strongly associated with early breastfeeding cessation,² decreasing the benefits of breastfeeding to mother and child.^1,3 Breastfeeding duration is influenced by maternal perception of self-efficacy in breastfeeding^4,5; and early initiation of supplementation can interfere with maternal confidence and impede lactogenesis.^6–8 Recognition of the public health importance of exclusive breastfeeding led the Healthy People 2020 Initiative⁹ to set goals of reducing the proportion of breastfed newborns receiving formula supplementation within the first 2 days of life from 24.2% to 14.2%. The WHO/UNICEF Baby-Friendly Hospital Initiative (BFHI) aims to reduce hospital practices which interfere with and enhance those that promote successful breastfeeding through its blueprint, the 10 Steps to Successful Breastfeeding.¹⁰ Step 6 specifically addresses supplementation, namely “to give newborns no food or drink other than breast milk unless medically indicated.” The Joint Commission on Hospital Accreditation has also charged hospitals to increase their exclusive breastfeeding rates and avoid unnecessary formula supplementation.¹⁰

Dehydration is considered a medical indication for supplementation if based not only on neonatal weight loss but also on the presence of clinical signs such as dry mucus membranes, sunken fontanelle, tenting, decreased urine output, and abnormal blood chemistries. In the nursery, newborns are routinely weighed on the night shift, and a weight loss of ≥10% from birth frequently triggers concern of mother and nursery staff for insufficient intake of breast milk and dehydration. This may lead to supplementation when other signs of dehydration are absent or not assessed. Studies have shown that the transfer of maternal intrapartum fluid may augment the infant's birth weight (BW).^11,12 Diuresis of this fluid by the infant occurs largely in the first 24 hours of life.^13–15 Some researchers have recommended using the 24-hour weight (24HW) instead of BW as the reference in calculating percentage weight loss for infants whose mothers received fluid during labor.^13,16 The mother–infant unit at Hartford Hospital, a designated Baby-Friendly Hospital since 2000, adopted this recommendation in March 2014, as a potential means to decrease unnecessary supplementation of breastfeeding infants.

Materials and Methods

Study design

We performed a retrospective chart review of breastfeeding infants born by C-sections before and after the implementation of the 24HW measurement into routine practice. The study excluded vaginal births as these infants are typically discharged 2 days after birth, whereas following C-section births, infants usually stay 3–4 days allowing for a longer monitoring period. All data were collected after discharge, and informed consent was waived. Patients were identified using the Women's Health perinatal dataset.

Outcome measures

We compared the supplementation rate during the hospital stay for infants born 1 year before and 1 year after implementation of the practice change. Subgroup analyses were performed for infants of primiparous and multiparous mothers. Three potential untoward outcomes during the hospital stay were assessed: infant's maximum percentage weight loss from BW, length of stay (LoS), and hyperbilirubinemia determined by peak transcutaneous bilirubin (TcB). Routine bilirubin screening is performed on all newborns at Hartford Hospital around 48 hours or for concern for jaundice.

Study period and subjects

Preintervention data were collected from January 1, 2013 to December 31, 2013 and postintervention from June 1, 2014 to May 31, 2015, allowing for a 2-month washout period after start of the implementation on March 25, 2014. Newborns of mothers who planned to breastfeed were included in the study if they met the following criteria: full term (39^0/7–41^6/7 weeks), appropriate for gestational age, singletons, delivered by Caesarean section with an Apgar score ≥8 at 5 minutes, did not require Neonatal Intensive Care Unit (NICU) transfer, and no formula supplements were received in the first 24 hours of life (Fig. 1). Twenty-three newborns in the postintervention group were excluded, as no 24HW was documented at the time when the chart was still lacking a specific place for recording it. The final study sample was 404 preintervention and 263 postintervention subjects.

FIG. 1.

Inclusion criteria and study sample. BW, birth weight; 24HW, 24-hour weight; NICU, Neonatal Intensive Care Unit.

Maternal data included age, parity, previous breastfeeding experience, insurance status, C-section type (planned or unplanned), length of labor, and volume of fluid received. Infant data included BW, 24HW (for the postintervention group only), number of voids and feeds in the first 24 hours of life, lowest weight achieved, maximum TcB level, LoS, and whether the baby was ever supplemented with formula during the hospital stay.

Weight measurement

All infants were routinely weighed at birth using Scale-Tronix^® Pediatric Scales 4802D (accurate to the nearest 1 g). The intervention required that nurses obtain the weight of all infants at 24(±1) hours of life. Subsequent daily weights were obtained per nursery routine on the evening shift. Nurses and providers were educated about the scientific evidence behind the 24HW and instructed to routinely consider this weight as baseline for subsequent weight loss calculation and assessment of feeding adequacy before initiating supplements based on BW alone. Before weighing infants, nurses were encouraged to counsel mothers that the infant weight loss in the first 24 hours was largely due to diuresis of intrapartum fluids and that the 24HW would serve as baseline for further weight loss. Nurses' feedback on how to integrate the practice change into their workflow resulted in clustering measurement of 24HW with the critical congenital heart disease screening mandated by the State of Connecticut. The infant flow sheet was revised to include a specific place to document 24HW, allowing for easy comparison with BW and daily weight. Subsequent daily weights were obtained as per routine on the night shift.

Statistical analyses

Group sample sizes of 194 preintervention (assuming a proportion of 0.4 infants supplemented with formula in this cohort) and 127 in postintervention (assuming a proportion of 0.25 infants supplemented with formula) achieve 80% power to detect a difference between the pre- and postintervention group proportions of 0.15. The test statistic used is a two-sided Z test with pooled variance. The larger sample sizes in the project (404 preintervention and 263 postintervention) allowed for subgroup analysis with sufficient power.

A significance level of 0.05 was used for all statistical tests. Chi-square and Fisher's exact tests were used to compare discrete variables and independent sample t-tests to compare continuous variables between groups.

Results

Demographics

There was no statistically significant difference between the two groups of subjects in terms of maternal ethnicity, insurance status and age, infant gender ratio, estimated gestational age, Apgar score at 5 minutes of life, BW, percentage delivered with labor, and the number of voids and feeds in the first 24 hours of life (Table 1).

Table 1.

Demographic Information of Subjects

Characteristics	Preintervention, n = 404	Postintervention, n = 263	p
Maternal ethnicity, n (%)
White	299 (74.0)	186 (70.7)	0.134^a
Hispanic	49 (12.1)	33 (12.6)
Black	42 (10.4)	23 (8.8)
Asian	12 (3.0)	17 (6.5)
Other	2 (0.5)	4 (1.5)
Insurance status, n (%)
Private	318 (78.7)	208 (79.1)	0.304^a
State	78 (19.3)	45 (17.1)
Uninsured	8 (2.0)	10 (3.8)
Maternal age, mean (SD), years	32.0 (5.1)	32.4 (5.3)	0.360^b
Infant gender, n (%)
Male	216 (53.5)	138 (52.5)	0.802^a
Female	188 (46.5)	125 (47.5)	0.802^a
EGA, mean (SD), weeks	39.3 (0.6)	39.4 (0.6)	0.371^b
5 Minutes Apgar score, mean (SD)	9.0 (0.1)	9.0 (0.2)	0.053^b
BW, mean (SD), grams	3503.9 (329.6)	3464.8 (312.0)	0.127^b
Delivery with labor, n (%)	146 (36.1)	78 (29.7)	0.083^a
No. of voids in 24 hours, mean (SD)	3.4 (1.8)	3.4 (1.7)	0.672^b
No. of feeds in 24 hours, mean (SD)	6.7 (2.4)	7.0 (2.4)	0.116

p-Value generated from chi-square test.

p-Value generated from independent t-test.

EGA, estimated gestational age; BW, birth weight; SD, standard deviation.

Supplementation

In the postintervention group, 27.4% of infants were supplemented, in comparison with 43.6% preintervention (p < 0.001; Table 2). Among primiparous mothers, the proportion of infants supplemented fell from 51.9% to 31.0% after the intervention (p < 0.001), whereas, in infants of multiparous mothers, the proportion supplemented showed a smaller but still significant decrease from 36.8% to 24.5% (p = 0.017).

Table 2.

Supplementation During the Hospital Stay

	Preintervention	Postintervention	p^a
Overall	n = 404	n = 263
Supplemented with formula, n (%)	176 (43.6)	72 (27.4)	<0.001^b
Exclusively breastfed, n (%)	228 (56.5)	191 (72.6)
Primiparous mothers	n = 181	n = 116
Supplemented with formula, n (%)	94 (51.9)	36 (31.0)	<0.001^b
Exclusively breastfed, n (%)	87 (48.1)	80 (69.0)
Multiparous mothers	n = 223	n = 147
Supplemented with formula, n (%)	82 (36.8)	36 (24.5)	0.017^c
Exclusively breastfed, n (%)	141 (63.2)	111 (75.5)
Infants losing ≥8% BW	n = 244	n = 164
Supplemented with formula, n (%)	121 (49.6)	43 (26.2)	<0.001^b
Exclusively breastfed, n (%)	123 (50.4)	121 (73.8)
Infants losing ≥10% BW	n = 97	n = 84
Supplemented with formula, n (%)	62 (64)	22 (26)	<0.001^b
Exclusively breastfed, n (%)	35 (36)	62 (74)

p-Values generated from Fisher's exact tests.

p < 0.001.

p < 0.05.

Among infants losing ≥8% of BW (a cutoff for clinical intervention recommended by the AAP¹), the supplementation rate dropped from 49.6% to 26.2% (p < 0.001) after the practice change. When a cutoff point of ≥10% weight loss from BW (commonly known as the “rule of thumb”) was used, 64% were supplemented preintervention compared with only 26% preintervention (p < 0.001).

Infant weight loss

Comparison between the pre- and postintervention group showed no significant difference in the distribution (p = 0.053; Table 3) or mean maximum percentage weight loss (p = 0.309; Table 4). No infant in either group experienced clinical dehydration requiring transfer to the neonatal intensive care unit during the hospitalization.

Table 3.

Weight Loss During Hospital Stay

Weight loss during hospital stay as percentage BW				p = 0.053^a
	<8%	8–10%	10–12%	12–14%	≥14%
Preintervention, n = 404	160 (39.6%)	147 (36.4%)	80 (19.8%)	17 (4.2%)	0 (0%)
Postintervention, n = 263	99 (37.6%)	80 (30.4%)	65 (24.7%)	16 (6.1%)	3 (1.1%)

Maximum weight loss as percentage 24HW (postintervention group only)
	<8%	8–10%	10–12%	12–14%	≥14%
Postintervention, n = 263	258 (98.1%)	5 (1.9%)	0 (0%)	0 (0%)	0 (0%)

p-Values generated from chi-square tests.

24HW, 24-hour weight.

Table 4.

Mean Maximum Weight Loss, Peak Transcutaneous Bilirubin, and Length Of Stay

	Preintervention, n = 404		Postintervention, n = 263
	Number	Percentage	Number	Percentage	p^a
TcB ≥15 mg/dL	5	1.3	0	0	0.176
	Mean (SD)	Range	Mean (SD)	Range	p^b
Peak TcB level, mg/dL	7.7 (3.7)	0–18.9	7.7 (3.5)	0–14.5	0.874
Maximum weight loss, % of BW	8.5 (2.1)	0.5–13.4	8.7 (2.4)	3.4–14.7	0.309
Maximum weight loss, % of 24HW	/	/	3.6 (2.1)	0–9.7	/
Length of stay, days	3.6 (0.6)	3–6	3.5 (0.6)	3–4	0.004^c

p-Values generated from chi-square tests.

p-Values generated from independent t-tests.

p < 0.01.

TcB, transcutaneous bilirubin.

TcB level and LoS

There was no significant difference between the two groups in mean peak TcB attained or the proportion of infants with a level ≥15 mg/dL (phototherapy level per AAP guidelines¹⁷ for full-term low-risk infants at 48 hours or high intermediate risk zone at 72 hours of life per the Bhutani nomogram¹⁸). There was a small decrease in mean LoS after the intervention from 3.6 to 3.5 days (p = 0.004). Notably, there was no significant difference in mean peak TcB or LoS pre- and postintervention for infants who lost ≥8% or ≥10% BW.

Weight loss at 24 hours (postintervention group only)

On average, infants lost 5.3% (standard deviation = 1.4%) of their BW in the first 24 hours with a range of 1.2–11.5%.

Those experiencing labor lost less weight (4.8% versus 5.5%; p < 0.001), had fewer voids (2.7 versus 3.8, p < 0.001), and fed less frequently (6.4 times versus 7.4 times, p < 0.001) in the first 24 hours of life, and their mothers received less fluid compared with those without labor. There was no statistical difference in their maximum weight loss during the hospital stay that occurred typically on day 2 or 3 of life (Table 5).

Table 5.

Effect of Labor on Infant Weight Loss

	Delivered with labor, n = 78	Delivered without labor, n = 165	p^a
Volume of fluid received, mean (SD)	1504.5 (458.4)	1638.9 (408.8)	0.023^b
No. of feeds in first 24 hours of life, mean (SD)	6.4 (2.3)	7.4 (2.4)	0.004^c
No. of voids in first 24 hours of life, mean (SD)	2.7 (1.4)	3.8 (1.7)	<0.001^d
24HW loss, % of BW (SD)	4.8 (1.3)	5.5 (1.3)	<0.001^d
Maximum weight loss, % of BW (SD)	8.7 (2.3)	8.6 (2.6)	0.850

Of the 263 postintervention infants, 20 did not have length of labor recorded and were thus excluded from this analysis.

p-Values generated from independent t-tests.

p < 0.05.

p < 0.01.

p < 0.001.

Discussion

This study demonstrates a reduction in supplementation of healthy term infants delivered by Cesarean sections after incorporating simple practice changes into routine care: namely measurement of 24HW and utilization of this weight rather than BW as baseline for calculation of neonatal weight loss, education of nurses, lactation consultants and providers, and counseling of parents on the effect of intrapartum fluid transfer on their infants' weight and the utility of 24HW.

The overall supplementation rate decreased from 43.6% to 27.4% after implementation of the intervention. Although the proportion of supplemented infants of multiparous mothers dropped significantly (36.8% to 24.5%), the effect was most dramatic (51.9% to 31.0%) in infants of primiparous mothers. Primiparous mothers experience greater anxiety about breastfeeding and are more likely to perceive an insufficient milk supply and request supplementation for their infants when notified of weight loss by nurses during routine weighing on the night shift. Education of staff and mothers about the effect of intrapartum fluids on BW and use of the 24HW as reference point for calculating weight loss may have alleviated some anxiety and reduced unnecessary supplementation. It is also possible that first-time mothers are more receptive to this information than multiparous women, who are less likely to change their feeding practices due to prior experience.

The high percentage of neonates losing ≥8% and ≥10% BW in both pre- and postintervention groups in our study is consistent with the study of Flaherman et al. on weight loss in infants delivered by C-sections.¹⁹ Our study found a dramatic reduction in supplementation of infants losing ≥8% BW (26.2% versus 49.6%) and ≥10% BW (26% versus 64%) after the intervention (Table 2). Thus, utilization of 24HW rather than BW as the baseline for estimation of infant weight loss may have prevented a rush to supplement. Since increased infant weight loss is common after C-sections, it is important that decisions to supplement these infants are not based on percentage weight loss from birth alone, but on clinical assessment of feeding and dehydration.

Only 5 of the 263 infants (2%) in the postintervention group lost ≥8% of 24HW (only 1 was supplemented) and none lost ≥10%. The low frequency of ≥8% weight loss from 24HW suggests the need for close monitoring, assessment, and possible intervention in infants reaching this level of weight loss.

It was important to consider potential untoward effects of the intervention. Statistical analyses showed that the mean and distribution of maximum percentage weight loss from BW did not differ significantly between the pre- and postintervention groups, despite less supplementation in the latter. However, the reduced supplementation rate in the postintervention group may explain a small increase in the proportion of infants losing ≥10% of BW (31.9% versus 24.0%). Since any infant with clinical concerns for dehydration would have received medically indicated supplementation, this finding may indicate a decreased tendency to supplement based on weight criteria alone.

There was no significant difference in hyperbilirubinemia between the two groups as measured by mean peak TcB level or percentage of infants with a level ≥15 mg/dL. The small but statistically significant shorter LoS in the postintervention group was possibly due to our institution's trend toward discharging mothers on the third rather than fourth day post-C-section, if doing well, and it is the mother's preference. It is reassuring that among infants who lost ≥8 or 10% BW, there were no significant differences in the three potential negative outcomes studied even though the supplementation rate was dramatically reduced postintervention.

The strength of this study is its large sample size and original nature. To our knowledge, using 24HW as the reference for weight loss calculation has surfaced in the literature only as a recommendation.^13,16 This study is the first to report its implementation into routine care in a Level 1 nursery and to demonstrate reduced in-hospital supplementation after its introduction. In addition, the study sought to assess safety of this practice change with respect to the three potential adverse effects measured and showed no increase in maximum weight loss, or hyperbilirubinemia during the 3–4 day hospitalization and no increased LoS in infants born in the year following the intervention.

A number of limitations of the study must be noted. We were unable to determine if there was an increase in the hospital readmission rate of newborns for dehydration and/or hypernatremia after implementation of the intervention. However, it was reassuring that there was no significant difference in maximum weight loss or hyperbilirubinemia between the two groups of infants over the hospital stay, and all infants met the same set of discharge criteria. Our study did not establish causality. We cannot exclude the possibility that unidentified secular trends in our mother–infant unit of our Baby-Friendly Hospital played a role in the overall reduction of supplementation, although this explanation is less likely in those losing ≥10% BW. We were also unable to determine which factors in the intervention contributed to the decrease in supplementation: 24HW measurement, utilization of this weight as reference for neonatal weight loss, nursery staff education, counseling of mothers, or a combination. The 24HW measurement itself increased awareness of nursing, pediatric, and lactation staff of usual weight loss on the first day of life when infant's intake is universally limited. Infants born by vaginal births were excluded from the study due to the inability to follow their feeding and weight for more than 2 days during their stay. However, since epidural anesthesia, accompanied by intravenous fluids and fluid boluses, is almost universal during vaginal births at our institution, we believe that using 24HW for subsequent weight loss calculation may also make clinical sense in these infants and will reduce unnecessary supplementation. This requires additional study for confirmation. Finally, we urge caution in extrapolating the results to early and late preterm infants who were also excluded from the study.

The relationship between labor and infant weight loss after C-sections warrants further investigation. In our study, infants who experienced labor lost less weight by 24 hours than those delivered without labor (4.8% versus 5.5% of BW), despite fewer voids and feeds. Over the entire hospital stay, however, there was no significant difference in their maximum weight loss (Table 5). Although accurate estimation of maternal fluid balance was unavailable, the decreased intravenous fluid volume in mothers who experienced labor before C-section is a possible explanation. An additional factor is labor-induced vasopressin release, promoting neonatal fluid retention and decreased voiding, resulting in less initial weight loss.^20–25

Conclusion

We have demonstrated that a simple practice change of measuring and using infant's 24HW for neonatal weight loss calculation, along with staff and parental education, can reduce supplementation and promote exclusive breastfeeding in healthy term infants delivered by Cesarean sections. This practice change was not associated with increased in-hospital weight loss, bilirubin, or LoS. Further studies should investigate the utilization of the 24HW in infants delivered vaginally, and early-term and late-preterm infants as well as post-discharge readmission rates for dehydration to confirm the safety of this practice before widespread implementation. However, results of this study infer that 24HW is an important additional parameter to include in the assessment of weight loss and hydration in healthy term breastfeeding newborn infants delivered by C-sections and whose mothers receive intrapartum intravenous fluids. If adopted by other mother–infant units, this practice may help toward meeting the public health goals of increasing the rate and duration of exclusive breastfeeding as recommended by the WHO/UNICEF BFHI,¹⁰ the AAP,¹ Healthy People 2020 National Goals,^9,26 and the perinatal core measures of the Joint Commission on Hospital Accreditation.¹⁰

Footnotes

Acknowledgment

The authors acknowledge and thank Dr. Sandra Motta, MD, FAAP, newborn hospitalist at Connecticut Children's Medical Center, for the initial literature search for the study; Mary A. Marshall-Crim, MSN, APRN, FNP, IBCLC, Department of Women's Health, Hartford Hospital, for contributing in the interpretation of results; Trudy Lerer, Dr. Zhu Wang, PhD, and the Research Department at Connecticut Children's Medical Center for statistical help, the nursing staff and lactation consultants of the Mother-Infant Unit at Hartford Hospital for their support and encouragement. The authors also thank Dr. Alison J. Draper, PhD, Maryann McGuire, RN, MPH, and Kathy Mallinson at Trinity College, Hartford, CT, for providing Ms. Deng the opportunity to participate in this project through the Health Fellows Program during her undergraduate study.

Disclosure Statement

No competing financial interests exist.

References

American Academy of Pediatrics Section on Breastfeeding. Breastfeeding and the use of human milk. Pediatrics, 2012; 129:e827–e841.

Howard

, Howard

, Lanphear

, et al. Randomized clinical trial of pacifier use and bottle-feeding or cupfeeding and their effect on breastfeeding. Pediatrics, 2003; 111:511–518.

Kramer

, Kakuma

. The optimal duration of exclusive breastfeeding: A systematic review. Geneva: WHO, 2002.

Ertem

, Votto

, Leventhal

. The timing and predictors of the early termination of breastfeeding. Pediatrics, 2001; 107:543–548.

Noel-Weiss

, Rupp

, Cragg

, et al. Randomized controlled trial to determine effects of prenatal breastfeeding workshop on maternal breastfeeding Self-Efficacy and breastfeeding duration. J Obstet Gynecol Neonatal Nurs, 2006; 35:616–624.

Nommsen-Rivers

, Chantry

, Peerson

, et al. Delayed onset of lactogenesis among first-time mothers is related to maternal obesity and factors associated with ineffective breastfeeding. Am J Clin Nutr, 2010; 92:574–584.

Marsha

. Delayed lactogenesis II. 2015. http://breastfeedingthegoldstandard.org/wordpress/wp-content/uploads/DelayedlactogenesisII-G4.pdf (accessed January 15, 2018).

Fewtrell

, Morgan

, Duggan

, et al. Optimal duration of exclusive breastfeeding: What is the evidence to support current recommendations?. Am J Clin Nutr, 2007; 85:635S–638S.

ODPHP, Maternal, Infant, and Child Health. www.healthypeople.gov/2020/topics-objectives/topic/maternal-infant-and-child-health/objectives

10.

World Health Organization UNICEF. Baby-friendly hospital initiative: Revised, updated and expanded for integrated care. Geneva: World Health Organization, 2009.

11.

Martens

, Romphf

. Factors associated with newborn in-hospital weight loss: Comparisons by feeding method, demographics, and birthing procedures. J Hum Lact, 2007; 23:233–241, quiz 242–245.

12.

Hirth

, Weitkamp

, Dwivedi

. Maternal intravenous fluids and infant weight. Clin Lact, 2012; 3:59–63.

13.

Noel-Weiss

, Woodend

, Peterson

, et al. An observational study of associations among maternal fluids during parturition, neonatal output, and breastfed newborn weight loss. Int Breastfeed J, 2011; 6:9.

14.

Chantry

, Nommsen-Rivers

, Peerson

, et al. Excess weight loss in first-born breastfed newborns relates to maternal intrapartum fluid balance. Pediatrics, 2011; 127:e171–e179.

15.

Mulder

, Johnson

, Baker

. Excessive weight loss in breastfed infants during the postpartum hospitalization. J Obstet Gynecol Neonatal Nurs, 2010; 39:15–26.

16.

Merry

, Montgomery

. Do breastfed babies whose mothers have had labor epidurals lose more weight in the first 24 hours of life. Academy of Breastfeeding Medicine News and Views. 2000; 6:3.

17.

American Academy of Pediatrics Subcommittee on Hyperbilirubinemia. Management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation. Pediatrics, 2004; 114:297–316.

18.

Bhutani

, Johnson

, Sivieri

. Predictive ability of a predischarge hour-specific serum bilirubin for subsequent significant hyperbilirubinemia in healthy term and near-term newborns. Pediatrics, 1999; 103:6.

19.

Flaherman

, Schaefer

, Kuzniewicz

, et al. Early weight loss nomograms for exclusively breastfed newborns. Pediatrics, 2015; 135:e16–e23.

20.

Pohjavuori

, Fyhrquist

. Hemodynamic significance of vasopressin in the newborn infant. J Pediatr, 1980; 97:462–465.

21.

Oosterbaan

, Swaab

. Amniotic oxytocin and vasopressin in relation to human fetal development and labour. Early Hum Dev, 1989; 19:253–262.

22.

DeVane

, Porter

. An apparent stress-induced release of arginine vasopressin by human neonates. J Clin Endocrinol Metab, 1980; 51:1412–1416.

23.

Leung

, McArthur

, McMillan

, et al. Circulating antidiuretic hormone during labour and in the newborn. Acta Paediatrica, 1980; 69:505–510.

24.

Rees

, Forsling

, Brook

. Vasopressin concentrations in the neonatal period. Clin Endocrinol (Oxf), 1980; 12:357–362.

25.

Parboosingh

, Lederis

, Ko

, et al. Vasopressin concentration in cord blood: Correlation with method of delivery and cord pH. Obstet Gynecol, 1982; 60:179–183.

26.

US Department of Health and Human Services, Office of Disease Prevention and Health Promotion. Healthy People 2020. Washington, DC, 2012. Retrieved from: https://www.healthypeople.gov/2020/topics-objectives/topic/maternal-infant-and-child-health/objectives (accessed January 15, 2018).