Comparison of the Effects of Different Skin-to-Skin Contact Onset Times on Breastfeeding Behavior

Abstract

Objective:

Skin-to-skin contact (SSC) between mother and child improves the rates of exclusive breastfeeding (EBF) in the neonatal period. This study evaluated the effects of two SSC onset times on breastfeeding behavior in the neonatal period.

Materials and Methods:

A multicenter clinical trial was conducted, with random allocation of participants to two different SSC onset times: immediate (at birth) and early (at 60 minutes of life). Low-risk neonates at birth were included. The researchers responsible for analyzing the data were blinded. The outcomes evaluated were early breastfeeding; EBF in the hospital, in the first week of life, and in the first month; and breastfeeding effectiveness in the neonatal period. Bivariate analyses were performed to evaluate the effect of the onset of SSC on breastfeeding indicators. The relative risk (RR) was reported as an effect measure.

Results:

A total of 297 neonates were included (immediate SSC, n = 148; and early SSC, n = 149). No differences were found in early breastfeeding (93.6% versus 90.6%; RR 1.6, 95% confidence interval 0.07–3.82), breastfeeding effectiveness, or EBF in the neonatal period. There was an earlier initiation of breastfeeding in the immediate SSC group (22 versus 27 minutes, p < 0.001).

Conclusions:

No differences in breastfeeding indicators in the neonatal period were observed between groups with different onset times of SSC (immediate versus early) in the neonatal sensitive period among low-risk neonates at birth.

Clinical Trial Registration Number: NCT02687685.

Introduction

Neonatal mortality is the leading cause of childhood death worldwide and occurs mainly in low- and medium-income countries.^1,2 This holds true in Colombia, where neonatal mortality represents 62% of deaths in children under 1 year, mainly in rural areas and areas with higher concentrations of poverty.³ There is also increased morbidity from preventable causes in low-risk neonates at birth in Colombia.^1,3,4 Within this framework, the Sustainable Development Goals for 2030 propose reducing neonatal mortality by ending preventable deaths.⁵

A determinant of the health outlook of low-risk neonates is suboptimal breastfeeding as falling ill and dying in the neonatal period are correlated with late initiation of breastfeeding and use of other food sources in this period.^6,7 For example, initiation of breastfeeding after the first hour of life doubles the risk of dying in the first month of life. In addition, partial breastfeeding increases the risk of neonatal sepsis and other infections (diarrhea and respiratory infection) compared with exclusive breastfeeding (EBF).⁸

The newborn's first 2 hours of life are a sensitive period and a critical window of time to achieve adequate EBF for the short and medium term.⁹ Mother–child separation in this period negatively impacts newborn breastfeeding, while skin-to-skin contact (SSC) between mother and child in the sensitive period improves breastfeeding indicators in the newborn.¹⁰ However, the prevalence of SSC and early and EBF in the neonatal period is low in Colombia and worldwide.^11–14 Consequently, improving the rate of SSC and breastfeeding in newborns is essential for newborn health.¹⁵

To the best of our knowledge, no studies have evaluated the effects of two different SSC onset times during the neonatal sensitive period (first 2 hours of life) on neonatal breastfeeding. This information would be useful to increase the evidence of the intervention, helping to standardize the intervention and improve its use in newborn care and leading to improved breastfeeding rates in the neonatal period.

This study evaluated the effects of two SSC onset times (immediate versus early) during the neonatal sensitive period on breastfeeding behavior in the neonatal period. Data for this study were obtained from the clinical trial, “Effect of the onset time of skin-to-skin contact at birth, immediate compared to early, on the duration of breastfeeding in full-term newborns,”¹⁶ which aimed to determine the effects of two SSC onset times, immediate (at the time of birth) and early (at 60 minutes of life), on EBF in the first 6 months of life.

Materials and Methods

The clinical trial protocol has been published.¹⁷ In this study, we present a summary of the original study. The protocol was approved by the ethics committee of the Universidad de La Sabana and La Samaritana University Hospital. The parents signed an informed consent form before inclusion in the study. A multicenter, parallel, randomized clinical trial was conducted in two secondary university and referral hospitals in Cundinamarca, Colombia.

A total of 297 newborns delivered vaginally and with low-risk criteria at birth were included. Newborns with congenital malformations or the need for resuscitation and newborns and/or mothers with indications for hospitalization in the immediate neonatal period or with known contraindications to breastfeeding were excluded. Potential participating mothers were included from week 35 of gestation, and the inclusion criteria were confirmed at the time of admission for delivery in the maternity ward. Allocation to the interventions was performed in the expulsive phase of labor based on randomly permuted blocks of size six. The allocation was kept hidden in an opaque envelope until the birth of the head. The researchers who performed the data analysis were blinded to the allocation.

SSC was defined as placing the naked newborn, with the head covered by a hat, on the mother's naked breasts, both covered by warm blankets for 60 continuous minutes. The intervention group had immediate SSC. It consisted of initiating SSC immediately after birth, performing thermoregulation and umbilical cord clamping during SSC, and postponing interventions for the newborn (evaluations, screenings, and vitamin K administration) until after the end of 60 minutes of SSC. The control group had early SSC. In this group, once the umbilical cord had been clamped by the attending physician, the neonate was laid under a radiant heat lamp, where newborn interventions were performed. Once finished, the neonate was dressed and placed in the mother's arms. When the neonate reached 60 minutes of life, SSC between mother and child was initiated. In both study groups, early breastfeeding was promoted and supported by the mother–child care group.

During the study, data were collected on indicators of lactation in the neonatal period such as early breastfeeding; Infant Breastfeeding Assessment Tool (IBFAT) score at discharge from the rooming-in unit and in the first week of life; and type of feeding in the hospital, in the first week of life, and in the first month of life. Based on these data, the following outcomes were defined:

Early breastfeeding: whether the newborn managed to complete effective breastfeeding in the first hour of life.

Time (in minutes) of early breastfeeding: the length of time the newborn spent breastfeeding in the first hour. With these first two observations and the time of birth, we calculated the baby's age (in minutes) at which this first breastfeed was completed.

Effectiveness of breastfeeding in the rooming-in unit (breastfeeding in the hospital) and in the first week of life (5–7 days): this was obtained using the IBFAT, which consists of six items, four of which are scored from 0 to 3, with a minimum score of 0 and a maximum of 12. The total score was recorded and categorized into effective (total score ≥10) and noneffective (total score <10) breastfeeding. The IBFAT also has a category to qualitatively evaluate the mother's satisfaction with breastfeeding: very pleased, pleased, fairly pleased, and not pleased.

EBF in the hospital (rooming-in unit), first week of life (5–7 days), and first month of life: for this outcome, a questionnaire was constructed based on the breastfeeding index, which was applied by direct interview with the mother before discharge from the rooming-in unit, at the 1-week follow-up, and by telephone at the first month. The mother was asked about the food offered to the newborn since the last assessment, which was categorized into EBF (exclusively offered breast milk as a source of food) and non-EBF (if some type of food and/or fluid different from breast milk was offered).

Statistical analyses

The qualitative variables are described as absolute and relative frequencies, and the quantitative variables, according to their distribution, are expressed as measures of central tendency, dispersion, and location. The distribution of quantitative variables was evaluated with the Shapiro–Wilk test.

To evaluate the effect of SSC onset time on qualitative variables (early breastfeeding, EBF, effective breastfeeding, and maternal satisfaction with breastfeeding), the chi-squared test was applied. Fisher's exact test was performed according to the number of expected cases per cell. The effect of SSC onset time on quantitative outcomes (time of initiation in minutes of early breastfeeding and IBFAT score) was evaluated with Student's t-test and/or the Mann–Whitney U test according to the distribution of the variable. As an effect measure, the relative risk (RR) was reported with its 95% confidence interval (CI). A p-value <0.05 was defined as statistically significant. Data were collected and managed on the REDCap platform, and the analyses were performed with IBM SPSS 26 software.

Results

A total of 297 infants were included in the study (n = 148 in the immediate SSC group and n = 149 in the early SSC group). The maternal and newborn characteristics are shown in Table 1. Seven neonates were lost to follow-up at 1 month (n = 4 in the immediate SSC group and n = 3 in the early SSC group), and no differences in the characteristics of patients who were lost to follow-up were observed (Fig. 1).

FIG. 1.

Flow diagram.

Table 1.

Baseline Characteristics of Groups

	Immediate skin-to-skin contact (n = 148)	Early skin-to-skin contact (n = 149)
Maternal sociodemographic characteristics
Age, years (median—IQR)	23 (8)	24 (5)
Marital status, n (%)
Domestic partnership	112 (75.7)	109 (73.2)
Separated/divorced	0	1 (0.6)
Married	14 (9.5)	11 (7.4)
Single	22 (14.9)	28 (18.8)
Socioeconomic stratum, n (%)
1	91 (61.5)	100 (67.1)
2	53 (35.8)	47 (31.5)
3	2 (1.3)	2 (1.3)
4	1 (0.6)	0
5	1 (0.6)	0
6	0	0
Educational level, n (%)
Primary education	12 (8.1)	19 (12.7)
Secondary education	95 (64.2)	85 (57)
Higher education	16 (10.8)	20 (13.4)
Graduate education	2 (1.3)	1 (0.7)
Technical, professional, and/or technological education	22 (14.9)	17 (11.4)
University or equivalent	1 (0.6)	7 (4.7)
Working mother, n (%)
Yes	107 (72.3)	109 (73.1)
No	41 (27.7)	40 (26.8)
Maternal clinical characteristics
Parity, n (%)
Yes	79 (53.4)	81 (54.4)
No	69 (46.6)	68 (45.6)
Antenatal appointments, n (%)
<4	12 (8.1%)	13 (8.7)
4–8	83 (56.1)	92 (61.7)
>8	53 (35.8)	44 (29.5)
Previous breastfeeding, n (%)
Yes	75 (94.9)	77 (95.1)
No	4 (5.1)	4 (4.9)
Live births, n (%)
1	41 (27.7)	50 (33.6)
2	30 (20.3)	17 (11.4)
3	6 (4.1)	9 (6)
4	2 (1.4)	3 (2)
5	0	1 (0.7)
6	0	1 (0.7)
Gravidity, n (%)
1	65 (43.9)	60 (40.3)
2	43 (29.1)	52 (34.9)
3	25 (16.9)	19 (12.8)
4	10 (6.8)	11 (7.4)
5	4 (2.7)	4 (2.7)
6	1 (0.7)	2 (1.3)
7	0	1 (0.7)
Intergenesic period, months (median—IQR)	36 (57)	34 (55)
BMI (median—IQR)	23 (4)	23 (3.7)
BMI classification, n (%)
Normal	105 (70.9)	95 (63.8)
Overweight	26 (17.6)	32 (21.5)
Obesity	13 (8.8)	12 (8.1)
Low weight	4 (2.7)	10 (6.7)
Smoking, n (%)
Yes	1 (0.7)	1 (0.7)
No	147 (99.3)	148 (99.3)
Newborn characteristics
Sex, n (%)
Male	66 (44.1)	71 (47.7)
Female	82 (55.4)	78 (52.3)
Birthweight, g (median—IQR)	3085 (535)	3130 (480)
Gestational age, Ballard score (median—IQR)	39 (2)	39 (1.5)
Height, cms (median—IQR)	49 (3)	50 (3)

BMI, body–mass index; IQR, interquartile range.

There were no differences in the percentage of neonates who achieved early breastfeeding (93.9% versus 90.6%; RR 1.6, 95% CI 0.67–3.82). However, breastfeeding was started earlier in the immediate SSC group (22 versus 27 minutes, p < 0.001) (Table 2). The time of initiation of breastfeeding (in minutes) was not associated with EBF in the hospital (p = 0.83) or in the first week of life (p = 0.4) (Table 3). Other outcomes also showed no differences between the study groups (Table 2).

Table 2.

Onset of Skin-to-Skin Contact and Neonatal Breastfeeding

	Immediate SSC	Early SSC	RR	95% CI	p
Early breastfeeding, n (%)
Yes	139 (93.9)	135 (90.6)	1.6	0.67–3.82	0.28
No	9 (6.1)	14 (9.4)	1.6	0.67–3.82	0.28
Time of early breastfeeding, minutes (median—IQR)	22 (20)	27 (13)			<0.001^*
EBF in the maternity ward, n (%)
Yes	147 (99.3)	147 (98.7)	2	0.17–22.29	0.50^**
No	1 (0.7)	2 (1.3)	2	0.17–22.29	0.50^**
Effectiveness of breastfeeding in the maternity ward, n (%)
Effective	134 (90.5)	132 (88.6)	1.23	0.58–2.6	0.58
Noneffective	14 (9.5)	17 (11.4)	1.23	0.58–2.6	0.58
IBFAT score in the maternity ward (median—IQR)	12 (1)	12 (1)			0.99^*
Mother's satisfaction with breastfeeding in the maternity ward, n (%)
Very pleased	101 (68.2)	105 (70.5)	1		0.75
Pleased	45 (30.4)	40 (26.8)	0.85	0.51–1.41	0.54
Fairly pleased	2 (1.4)	3 (2)	1.44	0.23–8.81	0.69
Not pleased
EBF in the first week, n (%)
Yes	139 (95.9)	140 (95.2)	1.1	0.38–3.53	0.79
No	6 (4.1)	7 (4.8)	1.1	0.38–3.53	0.79
Effectiveness of breastfeeding in the first week, n (%)
Effective	128 (88.3)	134 (91.2)	0.73	0.34–1.56	0.41
Noneffective	17 (11.7)	13 (8.8)	0.73	0.34–1.56	0.41
IBFAT score in the first week
Median (IQR)	12 (0)	12 (0)			0.99^*
Mother's satisfaction with breastfeeding in the first week, n (%)
Very pleased	102 (70.3)	100 (68)	1		0.60
Pleased	38 (26.2)	37 (25.2)	0.99	0.58–1.68	0.98
Fairly pleased	4 (2.8)	9 (6.1)	2.29	0.68–7.69	0.17
Not pleased	1 (0.7)	1 (0.7)	1.02	0.06–16.53	0.98
EBF in the first month, n (%)
Yes	138 (95.8)	138 (94.5)	1.33	0.45–3.94	0.60
No	6 (4.2)	8 (5.5)

Mann–Whitney U test.

Fisher's exact test.

CI, confidence interval; EBF, exclusive breastfeeding; IBFAT, Infant Breastfeeding Assessment Tool; IQR, interquartile range; RR, relative risk comparing immediate SSC versus early SSC; SSC, skin-to-skin contact.

Table 3.

Exclusive Breastfeeding of the Neonate and Time of Early Breastfeeding

	Yes	No	p^*
EBF at maternity ward discharge
Time of early breastfeeding, minutes (median—IQR)	25 (17)	24 (15)	0.83
EBF in the first week
Time of early breastfeeding, minutes (median—IQR)	25 (17)	23 (14)	0.4

Mann–Whitney U test.

EBF, exclusive breastfeeding; IQR, interquartile range.

Discussion

This study found that when SSC began at two different time points during the neonatal sensitive period (immediate versus early), no differences were observed between the two groups in terms of key indicators of breastfeeding in the neonatal period. In comparison with permanent separation at birth, SSC increases the rate of early breastfeeding, decreases the age at which the first breastfeed occurs, improves the effectiveness of the first breastfeed, and raises the likelihood of EBF in the first month of life.^18–20 In contrast, the results of the present study show that if SSC is applied in the first 2 hours of life (the sensitive period), avoiding permanent separation with no SSC in this time, there are no differences in these breastfeeding outcomes in the first month of life.

Although breastfeeding started at an earlier age in the immediate SSC group, when we evaluated whether this onset time was associated with the EBF status in the rooming-in unit, in the first week of life, and in the first month of life, we did not observe differences between the two groups. Safari et al.²¹ suggested that although they found an earlier initiation of breastfeeding in the SSC group than in the separation group (2.41 ± 1.38 versus 5.48 ± 5.7 minutes, p < 0.001), they opined that this difference was not clinically significant. Their conclusion is in line with the findings of the present study.

The IBFAT allows us to objectively evaluate the breastfeeding skills of the newborn and observe changes over time (first week).^22,23 Different studies using the IBFAT to evaluate the effectiveness of the first breastfeed have shown that SSC compared with separation at birth improves the success of the first breastfeed.^18,24 In contrast, in the present study, we used the IBFAT to evaluate the effectiveness of breastfeeding at different key moments of the neonatal period and observe its progression in the first week of life. The data we obtained show that there were no differences between the two SSC groups in breastfeeding effectiveness at the follow-ups performed. Additionally, the total IBFAT score in our study (median of 12 in both groups) was higher than that reported in other studies.¹⁸ We consider these reports important because a higher IBFAT score indicates better performance on the test and therefore better neonate breastfeeding skills at key moments.

Last, the breastfeeding status (EBF) in the hospital, in the first week, and in the first month was not different between the study groups. Again, SSC versus separation shows improvement in EBF at these key moments in the neonatal period.²⁵ The present study allows us to consider the nondifference in the percentage of neonates with EBF in the neonatal period when it begins at two different moments in the sensitive period of the neonate.

We propose that the findings of the present study regarding the nondifference in the neonatal breastfeeding indicators between the two SSC onset times can be explained by two factors. First is the strategy employed in the study. The intervention was carried out in institutions certified by the Baby-Friendly Hospital Initiative (BFHI), with personnel trained to give support for and resolve breastfeeding-related problems. Likewise, before data collection, an educational strategy was carried out to reinforce skills of the staff in breastfeeding and in the evaluation and monitoring of the mother and child using the IBFAT. BFHI certification and maternal and health personnel education are strategies that improve breastfeeding indicators.^10,26,27 Second, we propose that the mechanism of action of SSC is independent of the time of onset as long as it begins in the neonatal sensitive period and permanent separation is avoided (no SSC in this time). The mechanism of action of SSC has to do with its effect on the oxytocinergic system as a direct relationship is observed between SSC and oxytocin circulation in both mother and child.^28,29

During the neonatal sensitive period, SSC favors oxytocin release and neonatal physiological stability and increases the probability of breastfeeding success.³⁰ In the sensitive period, the neonate shows a sequential behavior known as breast crawl, which is associated with successful sucking.^9,31 Within this sequence, the neonate massages the nipple, stimulating the release of oxytocin,³² and at the same time, a mother–child interaction occurs that stimulates visual, tactile, auditory, and skin afferent sensory pathways in the mother and child, which lead to greater oxytocin release in both.³³ Thus, SSC allows multifactorial activation of the oxytocinergic system in the mother and child, and there is a direct relationship between SSC and the oxytocin levels of the mother and child.

Therefore, we propose that when this sensory and biochemical influx occurs in the neonatal sensitive period through the onset of SSC in the first hour of life, immediately or only early, it effectively improves the breastfeeding behavior, which together with the impact on milk letdown, the mother–child relationship, and bonding resulted in equal breastfeeding rates in both evaluated groups. These data shed light on the importance of SSC during the sensitive period, having a multidisciplinary breastfeeding team, and the support and monitoring of the mother–child at key moments in improving breastfeeding indicators. We propose that future research should address questions about the measurement of oxytocin and cortisol levels in the mother and child through prospective studies to establish the association between the onset times of SSC and serum levels of these markers. Likewise, such studies should address the impact of the onset of SSC on the medium- and long-term health outcomes of the mother and child.

A limitation of this study is the analysis of data collected in a controlled clinical trial to evaluate the impact of the onset of SSC on EBF in the first 6 months, as the sample size was calculated for this primary outcome. The sample size used and the few losses to follow-up for these outcomes stand out as strengths.

Conclusions

In summary, when SSC is applied to a group of low-risk neonates at birth at two different onset times in the neonatal sensitive period (immediate versus early) and permanent separation (no SSC) is avoided, no differences are observed between the groups in breastfeeding behavior during the neonatal period. Our findings suggest that the mechanism of action of SSC is maintained if it is initiated and maintained in the neonatal sensitive period.

Footnotes

Authors' Contributions

S.I.A was involved in conception and design of the work; analysis and interpretation of data; drafting the work or revising it critically for important intellectual content; and final approval of the version to be published. C.F.M., O.A.G., and E.A. were involved in the design of the work; acquisition, analysis, and interpretation of data; drafting the work or revising it critically for important intellectual content; and final approval of the version to be published. All authors agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All authors approved the final version of the manuscript.

Acknowledgment

The authors are grateful for the support provided by Hospital Universitario de La Samaritana Unidad Funcional de Zipaquira y Hospital El Salvador de Ubaté.

Disclosure Statement

No competing financial interests exist.

Funding Information

This research was funded by the Administrative Department of Science, Technology and Innovation (Departamento Administrativo de Ciencia, Tecnología e Innovación—COLCIENCIAS) (777-2017). Registration code 58068. Contract number 829 of 2017.

References

Lawn

, Blencowe

, Oza

, et al. Every newborn: Progress, priorities, and potential beyond survival. Lancet, 2014; 384:189–205.

Liu

, Oza

, Hogan

, et al. Global, regional, and national causes of under-5 mortality in 2000–15: An updated systematic analysis with implications for the Sustainable Development Goals. Lancet, 2016; 388:3027–3035.

Ministerio de salud. Análisis de Situación de Salud. Colombia, 2018. Published 2018. Available at https://www.minsalud.gov.co/sites/rid/Lists/BibliotecaDigital/RIDE/VS/ED/PSP/asis-colombia-2018.pdf (accessed February 9, 2021).

Jaramillo-Mejía

, Chernichovsky

, Martínez-Blanco

, et al. Exploratory analysis of preventable first day mortality in Colombia. Public Health, 2016; 138:74–85.

Medina

. Objetivos y metas de desarrollo sostenible. Desarrollo Sostenible. Available at https://www.un.org/sustainabledevelopment/es/objetivos-de-desarrollo-sostenible/ (accessed April 26, 2018).

Victora

, Bahl

, Barros

AJD

, et al. Breastfeeding in the 21st century: Epidemiology, mechanisms, and lifelong effect. Lancet, 2016; 387:475–490.

Debes

, Kohli

, Walker

, et al. Time to initiation of breastfeeding and neonatal mortality and morbidity: A systematic review. BMC Public Health, 2013; 13 Suppl 3(Suppl 3):S19.

Khan

, Vesel

, Bahl

, et al. Timing of breastfeeding initiation and exclusivity of breastfeeding during the first month of life: Effects on neonatal mortality and morbidity—A systematic review and meta-analysis. Matern Child Health J, 2015; 19:468–479.

Dani

, Cecchi

, Commare

, et al. Behavior of the newborn during skin-to-skin. J Hum Lact, 2015; 31:452–457.

10.

Bass

, Gartley

, Kleinman

. World Health Organization Baby-Friendly Hospital Initiative Guideline and 2018 Implementation Guidance. JAMA Pediatr, 2019; 173:93–94.

11.

Abdulghani

, Edvardsson

, Amir

. Worldwide prevalence of mother-infant skin-to-skin contact after vaginal birth: {A} systematic review. PLoS One, 2018; 13:1–19.

12.

Rojas-Higuera

, Londoño-Cardona

, Arango-Gómez

. Prácticas clínicas en el cuidado de gestantes y recién nacidos en algunos hospitales de Bogotá, Colombia. Rev Salud Pública, 2006; 8:223–234.

13.

Takahashi

, Ganchimeg

, Ota

, et al. Prevalence of early initiation of breastfeeding and determinants of delayed initiation of breastfeeding: Secondary analysis of the WHO Global Survey. Sci Rep, 2017; 7:44868.

14.

Encuesta Nacional de La Situación Nutricional ENSIN 2015. Colombia; 2018. https://www.minsalud.gov.co/sites/rid/Lists/BibliotecaDigital/RIDE/VS/ED/GCFI/libro-ensin-2015.pdf (accessed October 15, 2020).

15.

Nimbalkar

, Patel

, Nimbalkar

, et al. Infant and young child feeding practices in infants receiving skin to skin care at birth: Follow-up of randomized cohort. J Clin Diagn Res, 2016; 10:SC09–SC12.

16.

Agudelo

, Gamboa

, Acuña

, et al. Randomized clinical trial of the effect of the onset time of skin-to-skin contact at birth, immediate compared to early, on the duration of breastfeeding in full term newborns. Int Breastfeed J, 2021; 16:33.

17.

Agudelo

, Gamboa

, Rodríguez

, et al. The effect of skin-to-skin contact at birth, early versus immediate, on the duration of exclusive human lactancy in full-term newborns treated at the Clínica Universidad de La Sabana: Study protocol for a randomized clinical trial. Trials, 2016; 17:521.

18.

Karimi

, Sadeghi

, Maleki-Saghooni

, et al. The effect of mother-infant skin to skin contact on success and duration of first breastfeeding: A systematic review and meta-analysis. Taiwan J Obstet Gynecol, 2019; 58:1–9.

19.

Villa-Candel

, Duke

, Soriano-Vidal

, et al. Effect of early skin-to-skin mother-infant contact in the maintenance of exclusive breastfeeding. J Hum Lact, 2017; 34:304–312.

20.

Mahmood

, Jamal

, Khan

. Effect of mother-infant early skin-to-skin contact on breastfeeding status: A randomized controlled trial. J Coll Physicians Surg Pak, 2011; 21:601–605.

21.

Safari

, Saeed

, Hasan

, et al. The effect of mother and newborn early skin-to-skin contact on initiation of breastfeeding, newborn temperature and duration of third stage of labor. Int Breastfeed J, 2018; 13:1–8.

22.

Matthews

. Developing an instrument to assess infant breastfeeding behaviour in the early neonatal period. Midwifery, 1988; 4:154–165.

23.

Pados

, Park

, Estrem

, et al. Assessment tools for evaluation of oral feeding in infants less than six months old. Adv Neonatal Care, 2016; 16:143.

24.

Khadivzadeh

, Karimi

. The effects of post-birth mother-infant skin to skin contact on first breastfeeding. Iran J Nurs Midwifery Res, 2009; 14:111–116.

25.

Bramson

, Lee

, Moore

, et al. Effect of early skin-to-skin mother—infant contact during the first 3 hours following birth on exclusive breastfeeding during the maternity hospital stay. J Hum Lact, 2010; 26:130–137.

26.

Kalmakoff

, Gray

, Baddock

. Predictors of supplementation for breastfed babies in a Baby-Friendly hospital. Women Birth, 2018; 31:202–209.

27.

Balogun

, O'Sullivan

, McFadden

, et al. Interventions for promoting the initiation of breastfeeding. Cochrane Database Syst Rev, 2016; 11:CD001688.

28.

Vittner

, McGrath

, Robinson

, et al. Increase in oxytocin from skin-to-skin contact enhances development of parent-infant relationship. Biol Res Nurs, 2018; 20:54–62.

29.

Scatliffe

, Casavant

, Vittner

, et al. Oxytocin and early parent-infant interactions: A systematic review. Int J Nurs Sci, 2019; 6:445–453.

30.

Gómez

, Baiges

, Batiste

, et al. Kangaroo method in delivery room for full-term babies. An Esp Pediatr, 1998; 48:631–633.

31.

Widström

, Lilja

, Aaltomaa-Michalias

, et al. Newborn behaviour to locate the breast when skin-to-skin: A possible method for enabling early self-regulation. Acta Paediatr, 2011; 100:79–85.

32.

Thukral

, Sankar

, Agarwal

, et al. Early skin-to-skin contact and breast-feeding behavior in term neonates: A randomized controlled trial. Neonatology, 2012; 102:114–119.

33.

Moberg

, Handlin

, Petersson

. Neuroendocrine mechanisms involved in the physiological effects caused by skin-to-skin contact–With a particular focus on the oxytocinergic system. Infant Behav Dev, 2020; 61:101482.