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Introduction
Pacifiers are widely used in many parts of the world, despite the
fact that both the World Health Organization ()
and the American Academy of Pediatrics ()
advise against their use, especially with children who are being
breastfed. Research carried out in Brazil into all of the state
capitals with the exception of Rio de Janeiro, in October 1999,
revealed that 53% of children less than one year old were using
pacifiers ().
Many studies have shown an association between the use of a pacifier
and a shorter duration of maternal breastfeeding ().
The first study to be designed specifically to test this association
was carried out in Pelotas, in the south of Brazil, by Victora et
al. ().
In the study it was found that children who were still being breastfed
at one month of life and who frequently used a pacifier had a 2.4
times greater chance of being weaned in between one and six months.
This risk was reduced, but still significant (1.7 times), for children
using a pacifier less often.
According to some authors (),
the "suction confusion" caused by the differences in suction
techniques between a pacifier and the breast can interfere with
successful breastfeeding. Furthermore, children who use a pacifier
feed at the breast less often (),
which can interfere with maternal milk production.
Starting from the premise that bottles and pacifiers can be obstacles
to successful breastfeeding, the World Health Organization, in conjunction
with UNICEF, included not using bottles or pacifiers in maternity
units with breastfed children in their "Ten Steps to Successful
Breastfeeding" ().
As a result, Child-Friendly Hospitals (Hospitais Amigo da Criança), in addition to not using bottles or pacifiers in their
maternity units, also advise mothers to avoid these practices after
hospital discharge. There are no known studies investigating the
practice of pacifier use and its relationship with early weaning
of children born at Child-Friendly Hospitals. This article
is intended to fill that gap.
Methods
This is a longitudinal cohort study, which involved 250 children
born at the Hospital de Clínicas de Porto Alegre, a general
university hospital where approximately 4,000 births take place
a year. Its clientele comes from varying socioeconomic strata with
a predominance of individuals who have a low level of buying power,
users of the Sistema Único de Saúde (Brazilian National
Health System). The hospital was recognized as a Child-Friendly
Hospital in December 1997.
The sample was selected during the period from August 1999 to May
2000 and included all neonates born during the period who fulfilled
the following criteria: birth weight equal to or greater than 2,500
g; were not twins; had no health problems which impeded breastfeeding
or made it difficult (e.g.: HIV positive mother, congenital malformations,
conditions which made it necessary for mother and child to be in
different wards/units), were breastfeeding when discharged from
the maternity unit and were the children of mothers resident within
the municipality of Porto Alegre.
After agreeing to participate and signing an informed consent form,
the mothers were interviewed at the maternity unit in order to obtain
information about their sociodemographic characteristics and on
certain aspects related to pre-natal care, the birth and previous
experience of breastfeeding. Information related to pacifier use
and methods of feeding the child were obtained by interviews with
the mothers in their homes at the end of the first and sixth months
of life of the child and by telephone interviews at the end of the
second and fourth months. When telephone interviews were not possible,
home visits were resorted to. The children in the cohort were observed
until the sixth month of their lives or until breastfeeding was
interrupted if this occurred first. None of the mothers refused
to take part in the study. Thirteen (5.2 %) children were lost during
the first month of observation. As a result data relating to pacifier
use at one month relates to 237 children. Two hundred and twenty-eight
children remained within the study until the end of the six-month
observation period, an 8.4% sample loss due to failure to locate
their families on interview dates. Both at the maternity unit and
during follow-up, standardized questionnaires were used. Two of
the authors (M.E.S. & A.L.B.) performed both the sample selection
and the interviews at the maternity unit; home visits and telephone
interviews were the responsibility of medicine students who had
won Scientific Initiative scholarships and been duly trained for
the task. The quality of the information obtained on the follow-up
questionnaires was checked by the two authors mentioned above, and
compared with a second interview in approximately 5% of cases which
were selected by lots.
The maternal breastfeeding categories used in the study were those
defined by the World Health Organization (),
i.e. children whose only source of both nutrition and hydration
was human milk were considered to be receiving exclusive maternal
breastfeeding, children were considered to be receiving predominant
maternal breastfeeding, if, in addition to milk, they received
water, juice or teas and children who received any quantity whatsoever
of maternal milk were considered to be receiving maternal
breastfeeding, irrespective of whether they received other foods
or not. Partial breastfeeding was the term used when children
received other types of milk in addition to maternal milk and early
weaning was used to describe the situation of children whose
supply of maternal milk was interrupted during the observation period,
i.e. before the end of six months.
Children were categorized as pacifier users when their mother said
that they had the habit of using one and non-users when this
habit did not exist.
Epiinfo 6.0 and SPSS for Windows (version 8.0) were used
for the statistical analysis. Associations between pacifier use
and selected variables were tested using either the chi-square,
the Pearson or the chi-square with Yates' correction tests.
The sample was grouped into terciles with respect to the mother's
education and per capita income. The least educated tercile
included women who had spent less than seven years at school, the
middle tercile those mothers with 7 to 8 years' study and the upper
tercile mothers with more than 8 years' education. The lower, middle
and upper terciles for income corresponded to < 0.57 minimum
salaries (MS).< 0.58-1.2 MS and >1.2 MS. respectively.
Cox regression was used to calculate early weaning hazard ratios
(HR), according to a number of different variables and to calculate
risk of weaning for children who used pacifiers, taking into consideration
the pattern of breastfeeding at one month: the only variable which
was shown to be associated with both exposure (pacifier use) and
with outcome (early weaning). Cox regression was also used to calculate
the modifying effect of selected variables on the association between
pacifier use and early weaning. The variables, sex of child, race
of mother and type of birth were selected as they had been shown
to exercise a modifying effect on the relationship in an earlier
study (),
and the variables education and birth order due to their having
an association close to statistical significance with the use of
pacifiers and early weaning respectively.
In order to compare the prevalence of maternal breastfeeding with
that of exclusive maternal breastfeeding for users and non-users
of pacifiers, maternal breastfeeding survival curves were constructed,
and the log rank test employed to calculate statistical significance.
In order to avoid reverse causality distortions (weaning being the
cause of pacifier use and not the other way around), only children
who were being breastfed at the end of the first month were included
in the Cox regression and survival curves (n = 219).
The study was approved by the Scientific Commission and by the Commission
for Research and Ethics in Health of the Hospital de Clínicas
de Porto Alegre.
Results
Of the 250 mothers who started the study, (20.4 %) brought pacifiers
to the maternity unit with them and three (1.2 %) offered them to
the newborn. During the first month, the use of a pacifier was at
least attempted with 87.8% of the children, in the majority of cases
by the mothers (72.2 %). Fathers were responsible for offering the
pacifier in 2.5 % of cases and grandparents in 7.2%.
In the visit during the first month, it was found that, of the 237
children who were located, 91 (38.4%) were not using a pacifier
and 146 (61.6 %) were, the majority since the first week of life
(34.2 %).
The characteristics of the mothers and their children and also environmental
factors are given in Table 1, according to use or not of pacifiers
at one month. Pacifier use was most frequent among male children
and among those who were not being exclusively breastfed during
the first month. The association with the lower educational group
and pacifier use was very close to significance (p = 0.059).
Table 1 -
Characteristics of mothers and children
according to the use of pacifier at one month
Table 2 shows weaning risk during the first six months according
to environmental factors and the characteristics of mothers and
children. Firstborn children had a 48 % greater risk of being weaned
early when compared with children with older siblings. This difference
was very close to significance (95 % CI= 0.99 - 2.22).
Table 2 -
Incidence density ratios for weaning between
0 and 6 months according to mothers' and children's characteristics
Simple Cox regression revealed that maternal breastfeeding patterns
at one month was significantly associated with the risk of weaning
between one and six months. Children who were being partially breastfed
at one month had a 4.5 times greater risk (CI = 2.7 - 7.7) of having
been weaned by the sixth month and those being predominant breastfed
a 1.6 times greater risk (CI = 0.9 - 2.9) when compared with children
being exclusively breastfed.
The survival curves (Figures 1 and 2) show that maternal breastfeeding
and exclusive maternal breastfeeding frequencies among children
who were not using a pacifier during the first month were greater
than those of children who were. Observe that, for children who
were still being breastfed at one month, the incidence of weaning
between the second and sixth months was 22.4% for children who didn't
use a pacifier and 50.8% for pacifier users (p < 0.001). Seventy-three
percent of the children who used a pacifier had ceased being exclusively
breastfed by the end of their second month of life, whilst for children
who were not using pacifiers, this figure was 44.9% (p < 0.001).
Figure 1 -
Survival curve of breastfeeding
and use of pacifier in the first 6 months of life of children born at Hospital
de Clínicas de Porto Alegre.
Figure 2 -
Survival curve of exclusive
breastfeeding and use of pacifiers in the first 6 months of children born at the
Hospital de Clínicas de Porto Alegre.
As maternal breastfeeding patterns at one month were equally associated
with both the habit of using a pacifier and with early weaning,
thereby becoming a potential confusion factor, Cox regression was
used to analyze the relationship between pacifier use and early
weaning, controlled by this variable. The risk of early weaning
between one and six months for children who were still being breastfed
at one month remained significantly greater among the children who
used a pacifier (Table 3).
Table 3 -
Cox regression analysis of factors associated with weaning between 1 and
6 months (n = 219)*
Table 4 shows the results of the Cox regression for testing the
modifying effect of certain selected variables on the association
between pacifier use and early weaning. The risk of weaning as associated
with pacifier use was greater for boys, for children with older
siblings and for children who were born by caesarian, but these
interactions were not significant.
Table 4 -
Modifying effect of certain selected variables
on the association between pacifier use and early weaning*
Discussion
This study shows how deeply rooted the practice of offering pacifiers
is in local culture. Despite these children having been born in
a Child-Friendly Hospital, which discourages this practice, only
one in ten children was not offered a pacifier at home, and, by
the end of the first month of their lives, six out of ten children
were using a pacifier. The prevalence of pacifier use within the
population studied was similar to that found by Barros et al. ()
in Guarujá. SP (54.8 %), and less than that which was observed
in Pelotas, RS ()
(85 %). It is also lower than the prevalence of pacifier use by
children less than a year old for the general population of Porto
Alegre (69.2%), according to a national study performed under the
auspices of the Health Ministry, but greater than the average national
prevalence (53%) ().
According to the same research, Porto Alegre is the city with the
highest prevalence of pacifier use out of all the state capitals
in Brazil. It is possible that the prevalence of pacifier use within
the population studied was even higher before the implementation
of the Child-Friendly Hospital initiative although there is no available
data with which to verify this hypothesis.
Some studies have identified characteristics of mothers, their children
or their environment which favor pacifier use. Examples are: male
children ();
low birth weight babies ();
firstborn children ();
those who have been exposed to cigarette smoke ();
children of young mothers ();
or from a family with a low socio-economic level ().
In this study, pacifier use was more frequent among male children
and those whose mothers were less educated. It is possible that
better educated mothers are better informed and conscious of the
risks of pacifier use. It is also possible that these families have
living arrangements that favor a more tranquil atmosphere, and have
physical and emotional resources which better equip them to use
other methods of calming their children. The fact that boys are
more likely to use a pacifier still lacks an explanation. Could
boys have different behavior patterns from girls and so be offered
a pacifier more or often, or could girls have a tendency to reject
pacifiers more often? These questions would be best answered by
means of ethnographic studies.
The association between pacifier use and shorter maternal breastfeeding
duration, already described in other studies (),
was confirmed. Children who were still being breastfed at the end
of the first month of their lives and used a pacifier had a 2.8
times greater chance of being weaned by the sixth month. The chance
of reverse causality distortion was minimized by excluding those
children who were weaned during the first month of their lives.
Furthermore the association continued to be significant irrespective
of the pattern of breastfeeding at one month. Therefore, with respect
of a child using a pacifier when one month old, it is possible to
say that this child runs a considerably higher risk of being deprived
of the benefits of maternal breastfeeding before the end of the
sixth month than a child which does not, even if being exclusively
breastfed at one month. This fact is relevant to the attention which
has been given to mother/baby/family triage when attempting to prevent
early weaning.
Victora et al. ()
observed that the association between pacifier use and maternal
breastfeeding duration can be significantly modified by certain
factors, such as the mother's race and the type of birth. These
authors showed that pacifier use was only associated with maternal
breastfeeding duration with Caucasian women and that this association
was much stronger with women who had undergone caesarian deliveries
(HR = 9.1) when compared with those who had had vaginal delivery
(HR = 3.1). While the association was also stronger for girls (HR
= 5.4) than for boys (HR = 2.6) this difference was not statistically
significant. This study also revealed a stronger association between
pacifier use and early weaning among children born by caesarian,
although there was no statistical significance. In contrast with
Victora et al. (),
the association was stronger among boys - although once again without
statistical significance - and there was no difference between the
children of white and non-white mothers. Education and birth order
of the child also had no modifying effect on the association between
pacifier use and early weaning.
While the association between pacifier use and a shorter maternal
breastfeeding duration is already well established, the mechanisms
responsible remain unknown. According to some authors (),
the use of a pacifier reduces the number of times the child suckles
per day and, consequentially, there is less stimulation of the breast
and less milk production, culminating in weaning. Other authors
()
believe that the child who uses a pacifier has more difficulty in
obtaining milk from the breast because of "suction confusion"
caused by the differences in suction technique between the pacifier
and the breast, also culminating in weaning. Victora et al. (1997)
(),
using data from ethnographic research, concluded that the association
between pacifier use and early weaning is complex and that the pacifier
is a contributing factor to weaning among mothers who do not feel
entirely comfortable with breastfeeding. It is possible, according
to the authors, that the pacifier is an indication of difficulties
with breastfeeding and not the direct cause of weaning. Kramer et
al. (2001) ()
share this opinion. These and other authors ()
observed that pacifier use is more common when associated with breastfeeding
problems. The hypothesis that the population which does not insist
that its children use pacifiers is a differentiated population,
more conscious of the benefits of maternal breastfeeding and the
problems related to pacifier use and also more motivated to breastfeed
cannot be ruled out. The ideal method for testing this hypothesis
would be randomized clinical trials, but for ethical reasons this
is not possible. Ethnographic research can help reach an understanding
of the complex relationship between pacifier use and early weaning.
Concluding, pacifiers are widely used, even among populations which
have been advised against their use. The association between the
habit of pacifier use and early weaning has been confirmed. Irrespective
of the mechanisms involved in this association, children who use
pacifiers run a greater risk of not receiving the benefits of maternal
breastfeeding during the first 6 months of their lives. Health professionals
should be alert to this fact and attempt to intervene more intensely
to prevent weaning. It is also important to discuss the advantages
and disadvantages of pacifier use with mothers and society in general
in order that people can make conscious decisions.
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Introduction
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