Original Articleped_2892 817..820
Feeding on one side or both sides in a breast-feeding session
Meda Kondolot,1S. Songül Yalçin2and Kadriye Yurdakök2
1Social Pediatrics Unit, Department of Pediatrics, Erciyes University Faculty of Medicine, Kayseri and 2Social Pediatrics
Unit, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
Abstract Background: The aim of the present study was to examine the effects of breast-feeding method (on only one or on two
sides in a single feeding session) on growth, sleep duration and sucking period, and stool frequency.
Methods: Exclusively breast-fed healthy infants, aged 1–6 months, were included in the study during child health
follow-up visits. Mothers were given a questionnaire on sleep duration, sucking periods, and stool frequencies of their
Results: The height-for-age and weight-for-age z scores were signiﬁcantly higher in infants breast-fed from one side
during a single session than from both sides (P=0.002, P<0.001; respectively). Infants sucking on only one breast in
a breast-feeding session defecated signiﬁcantly less at night (P=0.005), their maximum sucking periods at night were
Conclusion: Breast-feeding at one side only during a single breast-feeding session increases growth, decreases stool
frequency and the maximum sucking period at night and does not inﬂuence the overall sleep pattern.
Key words breast-feeding method, defecation, growth, sleep, sucking period.
Breast-feeding has been the key for the survival of the human
species and its exclusive supply, for at least the ﬁrst 6 months of
life, should be provided to every infant.1–5 Mothers of healthy
babies who are breast-feeding should have no restrictions placed
on the frequency or length of their babies’ breast-feed. They
should be advised to breast-feed their babies whenever they are
hungry or as often as the baby wants.3,6 Fixed breast-feeding
schedules were introduced at the beginning of the 20th century in
an attempt to make infant feeding scientiﬁc and safe.7–9 These
ideas still prevail in some places, but more generally it is now
accepted that scheduling feeds leads to breast-feeding problems
and insufﬁcient milk production, which may cause mothers to
start artiﬁcial feeding. Restricting feed length may result in the
baby getting less of the energy-rich hindmilk.10 With demand
feeding, also known as ‘unrestricted’ or ‘baby led’ or ‘in response
to the baby’s cues’, the frequency and length of feeds varies both
between infants and from day to day.11 Breast-feeding from the
ﬁrst breast should be unlimited in time and both breasts need not
be routinely used at each feed.12
Various programs are currently being carried out to promote
breast-feeding,4as well as to investigate the impact of breast-
feeding methods, duration, and frequency of breast-feeding on
mother–infant pairs. The best method is baby-led breast-feeding.
Recommended breast-feeding starts with the breast not used in
the last breast-feeding period and continues until the infant stops
sucking; thus, it is ensured that the infant takes the hindmilk and
there is no need to offer the second breast unless the infant wants
it, which is again determined by the infant itself.10–13 Despite this
advice on breast-feeding method, there are limited studies on
infants fed on one side or both sides at a single feeding
The aim of the present study was therefore to compare infants
fed one or both breasts in a single feeding session in terms of
weight gain, sucking period in a breast-feeding session, sleep
duration, and stool frequency.
The study group included exclusively breast-fed healthy infants,
aged 1–6 months, who were admitted to Department of Social
Pediatrics of the Institute of Child Health at Hacettepe University
between October 2007 and February 2008 for child health
follow-up visits. This is a descriptive study and mothers were
asked to describe their babies’ breast-feeding method. Feeding
pattern was not taken into consideration in the ﬁrst 15 days. After
the 15 day postpartum period, infants taking only one breast in a
breast-feeding session were included in group S (n=105), infants
taking both breasts within 30 min of the session formed group D
(n=82). Infants using both breast-feeding methods, that is, one
breast in one session and both in the other one, infants with
partial breast-feeding or bottle feeding and infants who were
hospitalized, were not included in the study. We enrolled volun-
tary mothers if they fulﬁlled all entry criteria. Two hundred and
ten mothers fulﬁlled all entry criteria and 187 (89%) agreed to
participate in the interview. Mothers participating in the study
Correspondence: Meda Kondolot, MD, Erciyes University Faculty of
Medicine Department of Pediatrics, Unit of Social Pediatrics, 38010,
Kayseri, Turkey. Email: email@example.com
Received 19 September 2008; revised 17 March 2009; accepted 24
Pediatrics International (2009) 51, 817–820 doi: 10.1111/j.1442-200X.2009.02892.x
© 2009 Japan Pediatric Society
were given a questionnaire regarding their educational status and
sociodemographic characteristics of the family, and the infants’
age, sex, gestational week, birth order, birthweight, sucking
periods and sleep durations during the day and night, stool fre-
quencies, paciﬁer use, and unusual crying.
Anthropometry was measured on admission of the infants and
their previous measurements, if any, were recorded from their
ﬁles. Only recorded measurements were taken into consideration.
They were evaluated using the World Health Organization Mul-
ticentre Growth Reference Study (MGRS).15
All analyses were compared using SPSS for Windows (SPSS,
Chicago, IL, USA). The normality of data distribution was
checked using the Kolmogorov–Smirnov test. To compare
means, Student’s t-test was used for data with normal distribution
and Mann–Whitney U-test for skewed data. Covariance analysis
was used to detect the differences between group S and group D
for height-for-age and weight-for-age z scores after adjusting
birthweight, maternal education and maternal smoking and, for
birthweight after adjusting maternal education and maternal
smoking. The difference of case distribution between the groups
was analyzed using c2test. Fisher’s exact test was used when
applicable. P<0.05 was considered signiﬁcant.
Of the exclusively breast-fed infants who were included in the
study, 105 were breast-fed at one side only during a single
feeding session (group S), and 82 were breast-fed on both sides
(group D). The factors of age, gestational age, birthweight, sex,
maternal educational status, maternal smoking and birth order
were similar in both groups (Table 1). In group D birthweight
(and weight-for-age z score at birth) was slightly lower, maternal
smoking rate was higher and the level of maternal education was
lower than group S, but these are not statistically signiﬁcant (P>
0.05). After adjusting for maternal education level and maternal
smoking, no differences were detected in terms of birthweight
and z scores between the groups.
Although there were no signiﬁcant differences between the
two groups in terms of birthweight, it was detected that height-
for-age and weight-for-age z scores of group S were signiﬁcantly
higher than those for group D (P=0.002, P<0.001, respec-
tively). No signiﬁcant difference, however, was found with regard
to weight-for-height z scores (Table 2). After adjusting for birth-
weight, maternal education and maternal smoking, signiﬁcant
differences were found in height-for-age and weight-for-age z
scores of group S and group D (height-for-age z score [mean 1
SEM]: 0.63 10.09, 0.17 10.10 P=0.001; weight-for-age z score
[mean 1SEM]: 0.73 10.07, 0.34 10.09, P=0.001, respectively).
Stool frequency at night was found to be signiﬁcantly lower in
group S than group D (P=0.005). The mean maximum sucking
period in a breast-feeding session at night was signiﬁcantly lower
in group S (P=0.049). The mean maximum daytime sucking
period in a breast-feeding session was shorter in group S (19 min)
than group D (21 min), but the difference was not signiﬁcant.
Sleep duration was similar in the two groups. No difference was
observed between the groups in terms of paciﬁer use and unusual
crying (Table 2).
Current recommendation is to feed babies on demand, therefore
there is no prescribed pattern to breast-feed babies.16 During a
breast-feeding session, the baby may feed from one breast only,
feed from both breasts within 30 min, or the baby may have a
cluster of breast-feeds (feeding again from the ﬁrst breast within
30 min of feeding on the second).17 In a recent study of exclu-
sively breast-feeding infants between 1 and 6 months old in
Western Australia, 13% of infants always took both breasts, 30%
of infants always took one breast, and 57% of infants alternated.14
Breast milk lipids provide approximately 50% of the calories
in the milk, and the lipid content of breast milk increases through
a single feeding session from foremilk to hindmilk. Foremilk is
watered down milk, which is thirst-quenching, high in lactose but
low in fat and protein.18 It is known that the fat content of human
milk increases along with the emptying of the breast,19,20 while
other macronutrient compositions seem to change only slightly
or not at all.19,21 Hindmilk contains two–threefold the amount of
fat compared to foremilk, consequently supplying 104–146 kJ/
100 mL more energy, on average, than foremilk.21 Babies taking
hindmilk, rich in fat, although sucking one breast only during a
breast-feeding session are usually satisﬁed and do not want to
suckle the second breast. Ogechi et al. have shown that preterm,
very low-birthweight babies fed hindmilk gain weight signiﬁ-
cantly faster than those fed composite milk.18
In the present study weight-for-age and height-for-age z
scores were signiﬁcantly higher in infants breast-fed from one
Table 1 Infant characteristics vs breast-feeding method in a single
Fed one side only
Fed both sides
Age (months), mean 1SD 2.86 11.25 2.65 11.52
Male infants 62 (59) 43 (52)
Gestational age (weeks),
38.47 11.31 38.39 11.38
First child 61 (58) 42 (51)
Second 36 (34) 36 (44)
Third or higher range 8 (7.6) 4 (5)
Maternal education (years)
<11 9 (8.6) 13 (15.9)
311 96 (91.4) 69 (84.1)
Smoking at home
Yes 36 (34.3) 31 (37.8)
No 69 (65.7) 51 (62.2)
Yes 9 (8.6) 14 (17.1)
No 96 (91.4) 68 (82.9)
Birthweight (g), mean 1SD 3300 1434 3213 1424
Weight-for-age z score
(at birth), mean 1SD
-0.04 10.93 -0.21 10.91
*P>0.05 for comparison between groups.
818 M Kondolot et al.
© 2009 Japan Pediatric Society
side than both sides, but there was no signiﬁcant difference
between the two groups in terms of the weight-for-height z
scores. This situation has been attributed to the fact that the
hindmilk intake was fully completed in infants fed from one
breast only during a single breast-feeding session and thus, their
energy and calorie intake were higher than those infants breast-
fed from both sides and subsequently fed more foremilk richer in
lactose, with less fat content; causing their weight gain to be
lower when compared to the other group fed only one breast. This
is supported by the fact that there was no difference between the
birthweight-for-age z scores of the two groups. Furthermore, it
has been suggested that breast-feeding protects infants from
becoming overweight or obese. Although the precise magnitude
of this association remains unclear, several biological mecha-
nisms could explain the association. It was reported that breast-
feeding affects intake of calories and protein; insulin secretion;
and modulation of fat deposition and adipocyte development.22,23
Buyken et al. suggested that breast-feeding could offset a poten-
tial programming effect for childhood adiposity.24
Foremilk, poorer in fat content and calories than hindmilk, but
larger in volume, immediately ﬁlls up the stomach capacity,
which is still small in babies, leading to shorter gastric discharge
periods and more stool output in infants fed both sides. Because
the baby is not satisﬁed due to the relatively low fat content, the
infant continues sucking for a longer time and quickly gets
hungry. Also both stool frequency and the risk of the infantile
colic might be higher due to the lactose-rich content. In the
present study, defecation frequency of infants fed on one breast at
night were signiﬁcantly lower than in the other group (P=0.005).
These results conﬁrm those of previous studies.25,26 No signiﬁcant
relationship, however, has been detected between unusual crying
and breast-feeding from one or both sides during a single feeding
session. Furthermore, the mean of maximum sucking periods at
night in infants fed on one side was signiﬁcantly shorter than that
of infants fed on both sides (P=0.049). Daytime maximum
sucking periods were also shorter in infants fed on one side only,
but the difference was not signiﬁcant. It was suggested that these
infants were quickly satisﬁed due to their intake of hindmilk and
completed sucking in a shorter period of time.
Because of the aforementioned reasons, it was also suggested
that the sleep duration of infants fed on both sides was shorter,
causing them to get hungry more quickly, and initiate colic
attacks, but impact of the difference in breast-feeding method on
sleep duration and infantile colic was detected. This may be due
to the limited number of cases involved.
In some studies it was demonstrated that paciﬁer use short-
ened both sucking period in a breast-feeding session and duration
of breast-feeding.27–30 It has been shown that the sucking periods
during 24 h in infants who used paciﬁers during the ﬁrst 4 months
were 15–30 min shorter than in those who did not use paciﬁers,
and that they sucked less in a daily feeding session.30 The plau-
sible explanation for this is that mostly paciﬁer use within the
ﬁrst months of life hinders breast-feeding.11 In the present study
no difference was found for paciﬁer use in the two groups.
Because breast-feeding period and frequency are preferably
baby led, it is wise to ensure that the ﬁrst breast in each breast-
feeding session is fully emptied by the infant, because that will
help the infant to obtain hindmilk, which is richer in fat and
calories. This will enhance the growth in infants fed on one breast
only during a single feeding session. Also the maximum sucking
periods are shorter; and the stool frequency lower.
1 World Health Organization (WHO). Exclusive Breastfeeding.
[Accessed July 2008.] Available from: http://www.who.int/
2 Kamudoni P, Maleta K, Shi Z, Holmboe-Ottesen G. Infant feeding
practices in the ﬁrst 6 months and associated factors in a rural and
semiurban community in Mangochi district, Malawi. J. Hum. Lact.
2007; 23: 325–32.
Table 2 Height and weight vs breast-feeding method during a single feeding session
Fed one side only
Mean 1SD (median)
Fed both sides
Mean 1SD (median)
Height for age (z score) 0.65 11.06 (0.74) 0.14 11.13 (0.28) 0.002
Weight for age (z score) 0.77 10.82 (0.67) 0.28 11.00 (0.30) <0.001
Weight for height (z score) 0.51 10.96 (0.47) 0.33 11.06 (0.24) n.s.
Stool frequency in daytime 3.09 11.86 (3) 3.05 12.04 (3) n.s.
Stool frequency at night 0.64 10.78 (0) 1.03 10.98 (1) 0.005
Sleep duration (min)
Night-time 520 180 (480) 499 185 (480) n.s.
Daytime 331 1142 (360) 350 1121 (360) n.s.
Maximum sucking period in a breast-feeding session (min)
Night-time 16 17 (15) 20 112 (17.5) 0.049
Daytime 19 110 (15) 21 113 (17.5) n.s.
Minimum sucking period in a breast-feeding session (min)
Night-time 8 15 (5) 9 16 (5) n.s.
Daytime 8 16 (5) 7 15 (5) n.s.
Paciﬁer use, n(%) 36 (34.3) 30 (36.6) n.s.
Unusual crying, n(%) 30 (28.6) 30 (36.6) n.s.
daytime, 08.00–20.00 hours; night-time, 20.00–08.00 hours; n.s., not signiﬁcant.
Breast-feeding method 819
© 2009 Japan Pediatric Society
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© 2009 Japan Pediatric Society