The impact of teat and bottle design on nipple confusion: a double-blind randomized controlled trial

Abstract

Background: Nipple confusion has been reported in some infants who receive both breastfeeding and bottle feeding at early stage. Two types of nipple confusion including breast refusal (type A) and bottle refusal (type B) are described. Breast refusal may decrease maternal breast stimulation and result in low breast milk production while bottle refusal could create stress and prevent mothers from resuming their normal lives. This study aimed to explore whether the design of teat and bottle could influence the nipple confusion incidence, infant growth, feeding type and infant behaviors.
Method: A double-blind randomized controlled trial study has been conducted during June 2016 and September 2019. Forty normal eligible exclusively breastfed newborn-mother dyads with given informed consent were prospectively enrolled for 8 weeks of mixed feeding due to maternal return to work or study. They were randomly allocated into group A (Pigeon, Peristaltic PlusTM nipple, SS size) and group B (Philips, Avent NaturalTM Slow Flow nipple, SS size). All data including feeding type, milk intake, nipple confusion rate and infant behavior were collected for statistical analysis.
Result: Between 21 pairs of group A and 19 pairs of group B, nipple confusion was increasing from 22.5% to 50% during the study. Initially, bottle refusal was found 22.5% while breast refusal was more detected (32.5%) lately. Infant growth and development including weight, length, and head circumference were comparable in both groups. Infants in group A seemed to have lower breast refusal rate than infants in group B (28.6% vs 36.8%). Nevertheless, the bottle refusal rate was rather higher in group A than group B (23.8% vs 10.5%). The earlier the mixed feeding (< 5 weeks), the higher the nipple confusion rate (15% vs 7.5% at 4 weeks; 15% vs 35% at 12 weeks). Infant aerophagia, crying, abnormal latch-on and milk aspiration could be observed in both groups with no statistical difference while constipation was only observed in group B (5.3-15.8 %).
Conclusion: Nipple confusion could be found in exclusive breastfed infants after switching to mixed feeding. In Phillips’ group, nipple confusion rate was about 2 times higher than Pigeon’s group at 4 weeks, then, the rate was increasing to approximately 50% in both groups by 12 weeks. Aerophagia was more observed in Pigeon’s group while constipation was commonly found in Philips’ group. Early infant mixed feeding before 5 weeks could cause the higher nipple confusion rate and should be discouraged. As each product has both pros and cons, it has to be thoughtful to choose the proper design to achieve the infant’s need.

Full text

Page 1/16
The impact of teat and bottle design on nipple
confusion: a double-blind randomized controlled
trial
Pharuhas Chanprapaph (  pharuhasc@gmail.com )
Breastfeeding Unit, Department of Obstetrics and Gynaecology, Faculty of Medicine Siriraj Hospital,
Mahidol University
Sureelak Sutchritpongsa
Division of Developmental and Behavioral Pediatrics, Department of Pediatrics, Faculty of Medicine
Siriraj Hospital, Mahidol University
Pat Rojmahamongkol
Division of Developmental and Behavioral Pediatrics, Department of Pediatrics, Faculty of Medicine
Siriraj Hospital, Mahidol University
Siripan Chuchoang
Division of Developmental and Behavioral Pediatrics, Department of Pediatrics, Faculty of Medicine
Siriraj Hospital, Mahidol University
Jenjira Arthan
Breastfeeding Unit, Department of Obstetrics and Gynaecology, Faculty of Medicine Siriraj Hospital,
Mahidol University
Chulaluk Komoltri
Clinical Epidemiology Unit, Department of Research and Development, Faculty of Medicine Siriraj
Hospital, Mahidol University
Research Article
Keywords: bottle refusal, breast refusal, design, nipple confusion, randomized controlled trial
Posted Date: April 4th, 2022
DOI: https://doi.org/10.21203/rs.3.rs-1494783/v1
License:   This work is licensed under a Creative Commons Attribution 4.0 International License. 
Read Full License

Page 2/16
Abstract
Background: Nipple confusion has been reported in some infants who receive both breastfeeding and
bottle feeding at early stage. Two types of nipple confusion including breast refusal (type A) and bottle
refusal (type B) are described.Breast refusal may decrease maternal breast stimulation and result in low
breast milk production while bottle refusal could create stress and prevent mothers from resuming their
normal lives.This study aimed to explore whether the design of teat and bottle could inuence the nipple
confusion incidence, infant growth, feeding type and infant behaviors.
Method: A double-blind randomized controlled trial study has been conducted during June 2016 and
September 2019. Forty normal eligible exclusively breastfed newborn-mother dyads with given informed
consent were prospectively enrolled for 8 weeks of mixed feeding due to maternal return to work or
study.They were randomly allocated into group A (Pigeon, Peristaltic PlusTM nipple, SS size) and group B
(Philips, Avent NaturalTM Slow Flow nipple, SS size).All data including feeding type, milk intake, nipple
confusion rate and infant behavior were collected for statistical analysis.
Result: Between 21 pairs of group A and 19 pairs of group B, nipple confusion was increasing from 22.5%
to 50% during the study.Initially, bottle refusal was found 22.5% while breast refusal was more detected
(32.5%) lately. Infant growth and development including weight, length, and head circumference were
comparable in both groups.Infants in group A seemed to have lower breast refusal rate than infants in
group B (28.6% vs 36.8%). Nevertheless, the bottle refusal rate was rather higher in group A than group B
(23.8% vs 10.5%). The earlier the mixed feeding (< 5 weeks), the higher the nipple confusion rate (15% vs
7.5% at 4 weeks; 15% vs 35% at 12 weeks). Infant aerophagia, crying, abnormal latch-on and milk
aspiration could be observed in both groups with no statistical difference while constipation was only
observed in group B (5.3-15.8 %).
Conclusion: Nipple confusion could be found in exclusive breastfed infants after switching to mixed
feeding.In Phillips’ group, nipple confusion rate was about 2 times higher than Pigeon’s group at 4 weeks,
then, the rate was increasing to approximately 50% in both groups by 12 weeks.Aerophagia was more
observed in Pigeon’s group while constipation was commonly found in Philips’ group.Early infant mixed
feeding before 5 weeks could cause the higher nipple confusion rate and should be discouraged. As each
product has both pros and cons, it has to be thoughtful to choose the proper design to achieve the
infant’s need.
Background
The benet of breastfeeding to both mothers and neonates has been widely accepted. In term of
nourishment, breast milk is customized to match infant necessity. It is full of essential elements required
for early neonatal development.  Secretory IgA found in breast milk helps enhancing newborns’ immune
system and prevents them from severe infection.  Breastfeeding is also associated with mother-infant
bonding and improves both physical and mental development in the offspring.  For decades since World

Page 3/16
Health Organization (WHO) and United Nations International Children’s Emergency Fund (UNICEF) have
been supporting 6-month exclusive breastfeeding policy. They had launched “the Baby-friendly hospital
Initiative” to encourage health services globally to support breastfeeding by following “Ten steps to
successful breastfeeding”.(1)Nevertheless, breastfeeding rate still varies substantially between low- and
middle-income, and high-income countries. In European region, 6-month exclusive breastfeeding rate
varies from 22 % in United Kingdom to 72% in Sweden.(2) The study from Canada revealed that 73.65 %
of mothers discontinued breastfeeding before 6 months due to exhaustion (22.6%), uncertainty of
adequate milk volume (21.6%), return to work or study (20%) and medical complications.(3) Therefore,
several designs of infant feeding bottle and nipple that mimic natural infant suckling have been
introduced for breastfeeding contiunation. Thus, the baby can get breast milk through the bottle in day
time while the mother can directly breastfed her baby in the night time. However, nipple confusion can be
developed in some newborns.  Nifert M, et al. has described 2 types including breast refusal (type A) and
bottle refusal (type B).(4)Without immediate proper management, infant with breast refusal may decrease
maternal breast stimulation and result in breast milk production deterioration. In contrast, infant with
bottle refusal if left untreated, it can be very stressful for parents and prevent mother from going back to
normal life.
    In 2012, an experimental study in 63 exclusively formula-fed term infants found that bottle design
(the anti-vacuum infant feeding bottle from Philips AventTMvs the internal venting system from Dr
BrownsTM) had no signicant effects on infant milk intake or growth. However, infants who used the
former bottle had signicantly less reported fussing than those using the latter.(5)Later on, an
observational non-comparative prospective trial of ecacy of using a new design of bottle and nipple
(Pigeon Peristaltic PLUSTM, Japan) for continuation of breast feeding of neonates has been conducted
by the researchers from Russia.(6) The trial included 33 breastfed infants (20 full-term and 13 premature
newborns), age of 1-10 weeks, having mild or moderate perinatal lesions of central nervous system, with
low birth weight and/or premature infants capable of suckling without assistance. All of them required
temporary weaning due to supplementary or mixed feeding requirement, prolonged conjugated jaundice.
They were all switched to bottle feeding for 14 days before bringing back to breastfeeding. The data
revealed that 10 infants (30.3 %) with breast refusal at the beginning were clinically improved and there
was no breast refusal found by the end of the study. Furthermore, the number of children receiving
primarily breastfeeding was increased from 42.42 % to 78.78 %. Regarding functional digestive disorders
which may develop during bottle feeding, the study showed that the rate of aerophagia and colonics were
decreased by using this new devices. However, the lack of the control group in this study make the
ecacy of this novel design inconclusive and more information is still required. Currently, there are 2
different designs of infant nipples widely used including Pigeon Peristaltic PlusTM and Philips Avent
NaturalTM Slow Flow.
Methods

Page 4/16
Study aims
Theprimarily goal of the study aimed to explore whether the design of infant nipple and bottle could
inuence the nipple confusion incidence.Secondary, whether or not the nipple and bottle design could
affect infant growth, feeding type and behaviors would be explored.
Study design
The randomized controlled study design has been used to evaluate the inuence of nipple and bottle
design on nipple confusion, infant growth, feeding type and fetal behaviors
Study setting
During June 2016 and September 2019, the study has been conducted and collaborated between
Breastfeeding Unit, Department of Obstetrics and Gynaecology and Division of Developmental and
Behavioral Pediatrics, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University.
Participants
Healthy normal term singleton infants (37 weeks completed gestation, birthweight >= 2.5 kg), age 15-45
years old were recruited from postpartum ward. Exclusion criteria were: mother with abnormal breasts or
nipples, inadequate maternal milk volume, unable to speak Thai, infant with suckling and swallowing
disorders. All infants must have exclusively breastfed for at least 4-6 weeks with normal growth and
development and switching between breastfeeding and bottle feeding is required due to maternal return
to work or study.
Randomization
Mothers and newborns were routinely appointed from the postpartum ward to attend “Well Baby Clinic” at
the 4th week after delivery. The eligible participants were invited into the study and informed about the
research project. After having the written informed consent, a sealed opaque envelope containing a
specic code inside was chosen for each participant. The nQuery software was used to randomly
generate group A and group B in sequential order. All women will receive a package box lled with devices
accordingly (group A: Pigeon Peristaltic PLUSTM nipples (SS size), 160-ml Pigeon milk bottles x 4 sets;
group B: Philips, Avent NaturalTM Slow Flow nipples (SS size) and 160-ml Avent milk bottlesx 4 sets).
Each participant was also given one manual breast pump and breast milk storage bags for3 months.
Names and logos on any devices were deleted before giving to the participants. The research assistant
will demonstrate how to use and clean all instruments appropriately. Allparticipantsand
theirinfantswereasked to revisit at 4 and 12 weeks after enrollment according to their baby’s vaccination

Page 5/16
schedule. Each infant underwent physical examination, growth and development assessment, suckling
ecacyevaluation by pediatricians specialized in child development and behavior. A log book was given
to mother since the rst visit for recording her infant feeding type, breast milk intake, type & onset
ofnipple confusionand infant behavior twice a week. Finally, all information from log books were
collected for statistical analysis.
Denition
Nipple confusion
This term refers to an infant’s struggle with or preference for one feeding method over another after
exposure to bottle feeding or articial nipple. Two types of nipple confusion including breast refusal (type
A) and bottle refusal (type B) are classied.(4) After bottle feeding exposure, the exclusively breastfed
infant who denies breastfeeding will be diagnosed of breast refusal. On the other hand, the infant who
refuses bottle feeding will be diagnosed of bottle refusal.
Infant behaviors
Aerophagia is dened as a condition of excessive air swallowing while feeding and can cause
subsequent abdominal distention.(7) This functional digestive disorder could be found in premature
infants due to immaturity or infants with tongue and possible lip tie.(8) Aerophagia symptoms may
include cry at feeding, breast refusal, gastroesophageal reux disease (GERD)-like symptoms, colics and
vomiting.
From maternal observation, all infant behaviors including aerophagia (air swallowing), crying and
defecation were observed twice a week. Then, the occurrence of each behavior was graded into 3 levels
of none, few (2-3 times a day) and often (1 time in a hour).
From pediatrician observation, all infant behaviors including abnormal latch on, milk aspiration,
defecation were observed in every visit. The frequency of each behavior was graded into 3 levels of none,
few (2-3 times a day) and often (1 time in a hour).
Data collection
Maternal and infant demographic data such as age, ethnicity, parity, obstetrics history, infant gender,
route of delivery and birth weight were recorded. All information from the log book including feeding type,
milk intake, type and onset of nipple confusion and infant behavior were collected for statistical analysis
using.

Page 6/16
Data analysis
Descriptive statistics were used as appropriate, including N (%), mean ± standard deviation (SD). Median,
maximum and minimum were used for abnormal distribution data. Either Fisher Exact test or
independent samples T-test was used accordingly for the comparison of categorical or non-categorical
variables. P < 0.05 was considered statistically signicant. Statistical analysis was performed using
PASWÒ Statistics version 18.0 software (SPSS Inc., Chicago, IL, USA).
Ethic approval
Ethical approval was granted by the Institute of Research Board Committee, Siriraj Hospital Mahidol
University No. 318/2558 (EC1). The research project had been approved for registration at Thai Clinical
Trial Registry (TCTR20160516001).
Results
Initially, 90 mother-infant couples plus 10% of loss to follow-up cases were required with the total number
of 100 dyads were aimed to be enrolled. Due to time strain and mother’s work obligation, most of eligible
candidates were unable to make multiple visits accordingly. Although sample collection period has been
extended from 1.5 year into 3 years, there were nally 40 mother-infants dyads accomplished the
protocol. There were 21 cases allocated in group A and 19 cases in group B. Demographic data of all
participants in both groups at delivery and enrollment were indifferent. Mean maternal age, gestational
age, baby's birth weight and infant age at recruitment were 30.6 ± 6.70 years, 38.70 ± 0.89 weeks, 3,137.5
± 372.30 gram and 4.67 ± 0.5 weeks, respectively. Infant growth and development including weight,
length, and head circumference were comparable observed in both groups during the study. (Table 1) 
From Table 2, thenipple confusionrate was increasingly detected from 22.5% to 50% during 8 weeks. At
the beginning, only bottle refusal was found 9 out of 40 cases (22.5%). Later on, breast refusal was more
detected than bottle refusal (32.5 % vs 17.5%). Infant numbers with mixed feeding decreased from 31
(77.5%) to 20 (50 %) during the study. 
Regarding the impact of nipple and bottle design,nipple confusionrate in group A was lower than group
B at the beginning (14.3 % vs 31.6 %), then, it became higher in group A at 12 weeks (52.4% vs 47.4%).
Breast refusal was more prevalent in group B than group A (36.8 %vs 28.6%). However, there was no
signicantly difference of infant feeding types observed between 2 groups. (Table 2)
Concerning the onset of mixed feeding,nipple confusionrate in infants with early switching (before 5
weeks) was higher than infants with later switching (24 % vs 20% at 4 weeks and 56% vs 40% at 12
weeks). Nevertheless, there was no statistical signicance of infant feeding types found between 2
groups. (Table 2)

Page 7/16
From maternal log book’s record, aerophagia was more commonly found in infants group A (71.4 % vs
57.9 %), thereafter, it was decreasing in both groups (52.4 % vs 42.1 %).  Infant crying was more
prevalent in group A than group B (76.1 % vs 68.5 %), however, the number was declining at the end with
less prevalence in group A than group B (47.5 % vs 57.9 %). At rst, the number of infants with
constipation in group A was less than group B (19 % vs 26.3%), then, the number was increasing in both
groups (52.4 % vs 52.6%). (Table 4) 
From pediatricians’ observation, there was only one case of abnormal latch-on observed in group B
(5.3%). At rst, milk aspiration was not detected in both groups, thereafter, infants developed milk
aspiration in group B more than group A (57.9 % vs 47.6%).   Constipation was not found in infants
group A while in group B it was found increasing from 5.3 % to 15.8 %. (Table 5)

Discussion
In modern world, it is dicult for working mothers to prolong their breastfeeding as long as they need.
Although bottle feeding becomes more supportive, the early switching of feeding may be complicated by
nipple confusion in infants.(9)Our data conrmed thatnipple confusioncould be found in exclusively
breast-fed infants who switched tomix-fed infants from 22.5% to 50% during 8 weeks of mixed feeding. 
At the beginning, breast refusalwas more prevalent, thereafter, bottle refusal became more
detected.Interestingly, the onset of feeding switch seemed to affect thenipple confusionincidence. The
change from exclusive breastfeeding to mixed feeding before 5 weeks can cause the highernipple
confusionrate. Therefore, the early feeding switch should be extensively considered to avoid this
undesired consequence. 
To get success in breastfeeding, infant needs to establish good latch-on to maternal nipple and areola
and performs nutritive suckling and breast milk swallowing. Therefore, the design of nipple must replicate
maternal nipple both physical and functional features to establish nutritive suckling and minimizenipple
confusion. According to product’s information, the textured soft silicon surface of Pigeon Peristaltic
PlusTM nipple with widened base was designed to ease the baby to latch on, secure the attachment and
support peristaltic tongue movement during suckling.  On the other hand,the wide breast-shape nipple
with a exible spiral tip and unique petals of Philips Avent Natural Slow FlowTM nipple was applied to
make the nipple softer, more exible to promote latch-on and natural tongue movement. 
Apparently, nipple confusion found in both groups were not signicantly different. At rst, nipple
confusion rate in group B (Philips) was about 2 times higher than group A (Pigeon), thereafter, the rate
was increasing to approximately 50% in both groups.  Finally, the higher number of bottle refusal rate in
group A was noted (23.8 % vs 10.5%). According to product’s information, the contour and radius of
nipple-12mm for SS size in group A are crafted to t the baby’s mouth while its small hole is designed to

Page 8/16
make the baby drinking slowly and prevent milk aspiration. On the other hand, group B nipple is designed
with 2 small holes that offer a slow ow and features twin anti-colic valves which claimed to reduce colic
and discomfort. From maternal records, aerophagia was more commonly found in infants group A than
group B. For infant crying, it was initially more prevalent in group A than group B, then, it was declining
with the less prevalence in group A than group B later on. There was only one case of abnormal latch-on
noted in group B and milk aspiration rate was more observed in group B than group A. Regarding
constipation, it was commonly found in group B infants. This nding was unlikely to be associated with
nipple design but could possibly relate to the higher rate of breast refusal in this group.
According to Turti TV, et al, infants withbreast refusal were clinically corrected after using Pigeon’s nipple
and bottle for 2 weeks.(6) Our study found that infants using Pigeon’s nipple and bottle seemed to have
lower breast refusal rate than infants using Philips’ products (28.6% vs 36.8%). Nevertheless, the bottle
refusal rate was rather higher in Pigeon’s group than Philips’ group (23.8% vs 10.5%). While aerophagia
was more common in Pigeon’s group, constipation was prevalent in Philips’ group. Considering that each
product design has both pros and cons, it has to be thoughtful to choose the proper design to achieve the
infant’s need.  
Strength and limitation
To our best knowledge, this is the rst prospective experimental study that compares the impact of nipple
and bottle design on nipple confusion rate. Owing to the double-blind, randomized controlled study
design in which neither the participants nor the evaluators know which group they belonged to. This
strongly prevents bias in the research results. In term of data collection,infant physical examination,
growth and development assessment, suckling ecacyhave been thoroughly evaluated by specialists
while infant behavior was observed by both mother and clinicians. As a result, the study has high
reliability and validity. 
Initially, 100 mother-infant pairs were aimed to recruit for this study. Due to time strain and maternal
work obligation, most of eligible candidates were unable to make multiple visits accordingly. Despite
sample collection extension, there were only 40 mother-infants dyads accomplished the protocol. In the
future, the larger studied population and the longer study period (up to 6 months) should be encouraged.
Conclusion
Nipple confusion could be found in exclusively breast-fed infants from 22.5% to 50% after 12 weeks of
mixed feeding. In Phillips’ group, nipple confusion rate was about 2 times higher than Pigeon’s group at 4
weeks, then, the rate was increasing to approximately 50% in both groups by 12 weeks. Aerophagia was
more observed in Pigeon’s group while constipation was commonly found in Philips’ group. Early infant
mixed feeding before 5 weeks can cause the higher nipple confusion rate and should be discouraged.

Page 9/16
Declarations
Acknowledgement
None
Author’s contributions
P.C. developed research project, analyzed data and wrote the main manuscript.
S.S. developed research project, performed case follow-up, reviewed the manuscript.
P.R. performed case follow-up.
S.C. and J.A. collected all data.
C.K. performed statistical analysis.
Funding
The authors are grateful to Moong Pattana International Public Company Limited, Bangkok, Thailand for
funding and the supply of the devices for use in this study. 
Availability of data and materials
The datasets generated and/or analysed during the current study are not publicly available due to lack of
ethical approval for sharing but may be available from the corresponding author on reasonable request.
Declarations
Ethical approval [No. 318/2558 (EC1)] was granted by the Institute of Research Board Committee, Siriraj
Hospital Mahidol University. The research project had been approved for registration at Thai Clinical Trial
Registry (TCTR20160516001).
Consent for publication
Not applicable.
Competing interests
The authors have no conict of interest to declare. 
Author details
1. Breastfeeding Unit, Department of Obstetrics and Gynaecology, Faculty of Medicine Siriraj
Hospital,Mahidol University, 2 Wanglang Road, Bangkoknoi, Siririaj, Bangkok, Thailand 10700.

Page 10/16
2. Division of Developmental and Behavioral Pediatrics, Department of Pediatrics, Faculty of Medicine
Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkoknoi, Siririaj, Bangkok, Thailand
10700.
3. Clinical Epidemiology unit, Department of Research and Development, Faculty of Medicine Siriraj 
Hospital, Mahidol University, 2 Wanglang Road, Bangkoknoi, Siririaj, Bangkok, Thailand 10700.

References
1. Baby-Friendly Hospital Initiative: Revised, Updated and Expanded for Integrated Care. Geneva: World
Health Organization; 2009.
2. Bartington S, Griths LJ, Tate AR, Dezateux C, Millennium Cohort Study Health G. Are breastfeeding
rates higher among mothers delivering in Baby Friendly accredited maternity units in the UK? Int J
Epidemiol 2006; 35: 1178-86.
3. Brown CR, Dodds L, Legge A, Bryanton J, Semenic S. Factors inuencing the reasons why mothers
stop breastfeeding. Can J Public Health 2014; 105: e179-85.
4. Neifert M, Lawrence R, Seacat J. Nipple confusion: toward a formal denition. J Pediatr 1995; 126:
S125-9.
5. Fewtrell MS, Kennedy K, Nicholl R, Khakoo A, Lucas A. Infant feeding bottle design, growth and
behaviour: results from a randomised trial. BMC Res Notes 2012; 5: 150.
. Turti TV, Namazova-Baranova LS, Belyaeva IA, Zimina EP, Mitish MD, Bakovich EA, et al. Modern
methods of breast feeding maintenance in children with intestinal colics. Ped pharmacol 2014; 11:
55-8.
7. Chitkara DK, Bredenoord AJ, Wang M, Rucker MJ, Talley NJ. Aerophagia in children: characterization
of a functional gastrointestinal disorder. Neurogastroenterol Motil 2005; 17: 518–22.
. Siegel S. Aeropohagia induced reux in breastfeeding infants with ankyloglossia and shortened
maxillary labial frenula (tongue and lip tie). Int J Clin Pediatr 2017; 5: 6–8.
9. Zimmerman E, Thompson K. Clarifying nipple confusion. J Perinatol 2015; 35: 895-9.
Tables
Table 1
Patients’ demographic data in each group

Group A: Pigeon PeristalticPlusTM nipple (size SS), 160-ml Pigeon milk bottle

Page 11/16
Characteristic Data Group 
Total
N = 40
P-
value
A
(n =21)
B
(n = 19)
Maternal age (yr) 30.1 ± 6.69 31.21 ± 6.85 30.63 ± 6.70 0.606
Gestational age at delivery
(wk) 38.51 ± 0.99 38.91 ± 0.71 38.70 ± 0.89 0.161
Baby’s birth weight (g) 3,144.29 ±
409.90 3,130 ± 336.93 3,137.5 ± 372.30 0.905
At enrollment    
 Infant age (wk) 4.68 ± 047 4.66 ± 0.55 4.67 ± 0.5 0.909
 Infant weight (g) 4,279.29 ±
480.41 4,346.58 ±
422.39 4,311.25 ±
449.29 0.642
 Infant length (cm) 54.02 ± 2.18 54.10 ± 2.38 54.06 ± 2.25 0.916
 Infant head circumference
(cm) 37.06 ± 0.95 36.64 ± 1.33 36.86 ± 1.15 0.253
4 weeks after enrollment    
 Infant age (wk) 8.56 ± 0.6 8.44 ± 0.44 8.47 ± 0.53 0.724
 Infant weight (g) 5,208.33 ±
434.68 5,137.37 ±
923.31 5,174.63 ±
701.18 0.754
 Infant length (cm) 57.46 ± 2.17 57.24 ± 1.77 57.35 ± 1.97 0.729
 Infant head circumference
(cm) 38.63 ± 0.85 37.99 ± 1.23 38.33 ± 1.08 0.064
12 weeks after enrollment    
 Infant age (wk) 17.10 ± 0.68 17.25 ± 0.51 17.17 ± 0.6 0.427
 Infant weight (g) 6,485.48 ±
602.51 6,717.89 ±
678.99 6,595.87 ±
642.95 0.259
 Infant length (cm) 62.19 ± 2.73 62.28 ± 1.59 62.23 ± 2.24 0.891
 Infant head circumference
(cm) 40.77 ± 0.91 40.65 ± 1.05 40.72 ± 0.97 0.704
Group B: Philips, Avent NaturalTM Slow Flow nipple (size SS), 160-ml Avent milk bottle
Analysis test: independent samples T-test
Table 2

Page 12/16
Infant feeding type in both groups
Duration of study

Infant feeding type
4 weeks 

12 weeks
A
(n =21)
B
(n =19)
P-
value A
(n =21)
B
(n =19)
P-
value
Exclusive breastfeeding
(Bottle refusal or nipple confusion
type B)
3
(14.3
%)
6
(31.6
%)
0.265 5
(23.8
%)
2
(10.5
%)
0.583
Mixed feeding 18
(85.7
%)
13
(68.4
%)
10
(47.6
%)
10
(52.6%)
Bottle feeding only
(Breast refusal or nipple confusion
type A)
0

0 6
(28.6
%)
7
(36.8
%)
Group A: Pigeon PeristalticPlusTM nipple (SS), 160-ml Pigeon milk bottle
Group B: Philips, Avent NaturalTM Slow Flow nipple (SS), 160-ml Avent milk bottle
Analysis test: Fischer Exact test
Table 3
Onset of feeding type switching and infant feeding type in 2 groups

Page 13/16
Onset of feeding
type switching Infant feeding type 4 weeks after
enrollment 12 weeks after enrollment
A (n
=21) B (n
=19) P-
value A (n
=21) B (n
=19) P-
value
Early (< 5week) Exclusive
breastfeeding
(Bottle refusal or nipple
confusion type B)
2
(18.2
%)
4
(28.6
%)
0.661 3
(27.3
%)
1
(7.1%)
0.491
Mixed feeding 9
(81.8
%)
10
(71.4
%)
4
(36.4
%)
7
(50.0%)
Bottle feeding only
(Breast refusal or
nipple confusion type
A)
0 0 4
(36.4%)
6
(42.9%)
Late
(³5th week)
Exclusive
breastfeeding
(Bottle refusal or nipple
confusion type B)
1
(10.0
%)
2
(50
%)
0.242 2
(20.0
%)
1
(20.0
%)
1.0
Mixed feeding 9
(30.0
%)
3
(60
%)
6
(60.0
%)
3
(60.0
%)
Bottle feeding only
(Breast refusal or
nipple confusion type
A)
0 0 2
(20.0%)
1
(20.0%)
Group A: Pigeon Peristaltic PlusTM nipple (SS), 160-ml Pigeon milk bottle
Group B: Philips, Avent NaturalTM Slow Flow nipple (SS), 160-ml Avent milk bottle
Analysis test: Fischer Exact test
Table 4
 Fetal behavior observed by mother in both groups

Page 14/16
Fetal Behavior 4 weeks after enrollment 12 weeks after enrollment
A (n
=21) B (n
=19) P-
value A (n
=21) B (n
=19) P-
value
Aerophagia

None 6
(28 .6%)
8
(42.1 %)
0.728 10
(47.6 %)
11
(57.9 %)
0.545
Few
(2-3 times a day)
13
(61.9 %)
9
(47.4 %)
11
(52.4 %)
8
(42.1 %)
Often
(1 time in an
hour)
2
(9.5 %)
2
(10.5 %)
0
(0 %)
0
(0 %)
Crying None 5
(23.8 %)
6
(31.6 %)
0.480 11
(52.4 %)
8
(42.1 %)
0.897
Few
(2-3 times a day)
12
(57.1 %)
12
(63.2 %)
8
(38.1 %)
9
(47.4 %)
Often
(>3 times a day)
4
(19.0 %)
1
(5.3 %)
2
(9.5 %)
2
(10.5 %)
Defecation None 4
(19 %)
5
(26.3 %)
0.758 11
(52.4 %)
10
(52.6 %)
1.00
Few
(2-3 times a day)
13
(61.9 %)
9
(47.4 %)
8
(38.1 %)
8
(42.1 %)
Often
(>3 times a day)
4
(19.0 %)
5
(26.3 %)
2
(9.5 %)
1
(5.3 %)
Group A: Pigeon Peristaltic PlusTM nipple (SS), 160-ml Pigeon milk bottle
Group B: Philips, Avent NaturalTM Slow Flow nipple (SS), 160-ml Avent milk bottle
Analysis test: Fischer Exact
Table 5
 Fetal behavior observed by pediatrician in both groups.

Page 15/16
Fetal Behavior 4 weeks after enrollment 12 weeks after enrollment
A (n
=21) B (n
=19) P-
value A (n
=21) B (n
=19) P-
value 
Abnormal latch
on None 21
(100 %)
18
(94.7
%)
0.475 21
(100 %)
18
(94.7
%)
0.475 
Few 0
(0 %)
1
(5.3 %)
0
(0 %)
1
(5.3 %)

Milk aspiration None 21
(100%)
19
(100 %)
0.354 11
(52.4
%)
8
(42.1
%)
0.897 
Few
(2-3 times a
day)
0
(0 %)
0
(0 %)
8
(38.1
%)
9
(47.4
%)

Often
(>3 times a
day)
0
(0 %)
0
(0 %)
2
(9.5 %)
2
(10.5
%)

Defecation None 0
(0 %)
1
(5.3%)
0.098 0
(0 %)
3
(15.8
%)
0.042 
Few
(2-3 times a
day)
21
(100 %)
16
(84.2
%)
21
(100 %)
15
(78.9
%)

Often
(>3 times a
day)
0
(0 %)
2
(100 %)
0
(0 %)
1
(5.3 %)

Group A: Pigeon Peristaltic PlusTM nipple (SS), 160-ml Pigeon milk bottle
Group B: Philips, Avent NaturalTM Slow Flow nipple (SS), 160-ml Avent milk bottle
Analysis test: Fischer Exact
Figures

Page 16/16
Figure 1
A) Pigeon Peristaltic PlusTM nipple (size SS), 160-ml Pigeon milk bottle B) Philips, Avent NaturalTM Slow
Flow nipple (size SS), 160-mlAvent milk bottle
Figure 2
Study ow