previous breastfeeding practices and duration of exclusive breastfeeding in united states
DESCRIPTION
health and psychologyTRANSCRIPT
Previous Breastfeeding Practices and Duration of ExclusiveBreastfeeding in the United States
Ghasi Phillips • Kate Brett • Pauline Mendola
Published online: 12 October 2010
� Springer Science+Business Media, LLC (outside the USA) 2010
Abstract We examined the influence of duration of
exclusive breastfeeding (DEBF) for a mother’s earlier
children on the DEBF for her later children among mul-
tiparous women from the 2002 National Survey of Family
Growth. DEBF was categorized as: never breastfed (NBF)
(referent); not exclusively breastfed or exclusively breast-
fed for\4 months (EBF \ 4); and exclusively breastfed for
C4 months (EBF C 4). We examined DEBF using weigh-
ted percentages and odds ratios (OR) with 95% confidence
intervals (CI) from multinomial logistic regression models,
adjusting for maternal factors. About 70% of multiparous
women (n = 2,149) repeated the duration of exclusive
breastfeeding of their first child for their second child; 14%
of women repeated EBF C 4. Among multiparous women,
the adjusted odds ratio for EBF C 4 for second children was
7.2 (95% CI = 4.0–12.9) when first children were EBF \ 4
and 90.7 (95% CI = 45.4–181.4) when first children were
EBF C 4, relative to NBF first children. In analyses where
DEBF of third children was the outcome, odds of EBF C 4
were more strongly influenced by DEBF of second children
while the impact of DEBF of first children was not as
strong. Older maternal age and being married were related
to an increased DEBF. Being married at second birth
predicted a change from NBF for first children to EBF C 4
for second children (OR = 6.2, 95% CI = 2.7–14.2). In
conclusion, mothers generally repeated the DEBF of their
previous child. For third children, DEBF of the second child
was more likely to be repeated than that of the first child.
Keywords Birth order � Exclusive breastfeeding �Infant feeding � Maternal behavior
Introduction
Exclusive breastfeeding reduces the risk of adverse health
outcomes such as breast and ovarian cancers in mothers
and diarrhea, respiratory tract infections, and atopic dis-
eases in children [1, 2]. For a number of years, women
were encouraged to exclusively breastfeed their infants for
4–6 months [3]. Currently, the World Health Organization,
the American Academy of Pediatrics, and other health
organizations recommend exclusive breastfeeding through
the first 6 months of life. Approximately 14% of women in
the United States breastfed their infant exclusively for
6 months in 2006 [4], less than the 17% target for Healthy
People 2010 [4].
To improve the duration of exclusive breastfeeding, it is
important to first understand how multiple factors influence
breastfeeding practices. Studies have consistently shown
positive associations between increased duration of
breastfeeding and demographic (e.g. older age, married,
and higher education), biological (e.g. sufficient milk
supply), and social (e.g. familial and peer support) factors
[5]. Previous breastfeeding practices, however, have been
examined less frequently. Recent reports have shown that
mothers tend to repeat the breastfeeding practices of pre-
vious children with later children [6–9] but these studies,
G. Phillips (&)
Epidemic Intelligence Service, Office of Workforce and Career
Development, Centers for Disease Control and Prevention,
Atlanta, GA, USA
e-mail: [email protected]
G. Phillips � K. Brett � P. Mendola
Infant, Child, and Women’s Health Statistics Branch,
Office of Analysis and Epidemiology, National Center for Health
Statistics, Centers for Disease Control and Prevention,
Hyattsville, MD, USA
123
Matern Child Health J (2011) 15:1210–1216
DOI 10.1007/s10995-010-0694-4
with the exception of one [9], were conducted outside the
United States [6, 7] or were not nationally representative
[8].
Taylor et al. [9] used data from the 2002 National
Survey of Family Growth (NSFG) to examine the impact
of birth order on breastfeeding initiation. The authors
speculated that compared with children of lower birth
order, the likelihood of breastfeeding children of higher
birth order would decrease as family size and demands
increased. Instead, they found that women who breastfed
their first child were likely to also breastfeed subsequent
children, irrespective of the number of children they had.
Our study builds on the work of Taylor et al. by using
the 2002 NSFG to examine the influence of duration of
exclusive breastfeeding for a mother’s earlier children on
the duration of exclusive breastfeeding for her later chil-
dren. We also investigated whether maternal demographic
factors influenced the duration of exclusive breastfeeding
of second children, given the duration of exclusive
breastfeeding of first children.
Materials and Methods
Study Design and Population
The 2002 NSFG is a nationally-representative population-
based survey conducted by the National Center for Health
Statistics. Voluntary and confidential in-person interviews
were completed by 7,643 females 15–44 years of age,
corresponding to a response rate of 80% [10]. The analytic
sample for our study was limited to women with two or
more live births (n = 2,894), all of which were singletons
(n = 2,756) who were less than 19 years of age at inter-
view (n = 2,271). Including women with complete and
plausible data on breastfeeding initiation and age at sup-
plementation for up to their first three children, resulted in
data on 2,149 women and their 5,095 first-, second-, and
third-born children.
Assessment of Study Variables
All data for this cross-sectional study were self-reported.
The respondent was asked whether she had ever breastfed
each of her children \19 years of age at the time of
interview. Those who responded yes were asked about the
infant’s age (in months) at first supplementation. Using
responses to these questions, we created the main variable
of interest, duration of exclusive breastfeeding, which
was categorized into three levels: (1) never breastfed, (2)
not exclusively breastfed or exclusively breastfed for
\4 months, and (3) exclusively breastfed for C4 months.
The second category is subsequently referred to as
exclusively breastfed for\4 months. We chose a cut-point
of 4 months to increase our sample size and maximize
our statistical power, though this value is 2 months less
than the current recommendation of 6 months. The main
exposure and outcome variables were based on both the
duration of exclusive breastfeeding and the birth order of
siblings. Our two main outcome variables were duration of
exclusive breastfeeding for the second child and duration
of exclusive breastfeeding for the third child. The main
exposure variables of interest for these two outcomes were
duration of exclusive breastfeeding for the first child and
duration of exclusive breastfeeding for the first two chil-
dren, respectively.
Maternal age at birth (B25 and [25 years), marital
status at birth (married and unmarried), and race/ethnicity
(Non-Hispanic (NH) white, NH black, Hispanic, and other)
were controlled as known predictors of breastfeeding and
assessed for their influence on changes in breastfeeding
practices between first and second children.
Statistical Analyses
We analyzed duration of exclusive breastfeeding among
the children in our analytic sample by maternal demo-
graphic characteristics and compared differences using chi-
square tests. Our main analyses, however, used the mother
as the unit of analysis given our interest in examining
breastfeeding duration patterns for siblings born to the
same mother.
We estimated the duration of exclusive breastfeeding for
sibling sets of two or more (2,149 mothers) and three or
more (797 mothers). In analyses for mothers with at least
three children, selected categories were collapsed to
improve precision. Analyses did not continue for sibling
sets of four or more given that statistical power was limited
by small sample sizes.
Since our two main outcome variables had three levels,
we used multinomial logistic regression [11] to model the
odds of exclusive breastfeeding for \4 months and
C4 months compared to never breastfeeding of the index
child, controlling for maternal demographics at the time of
the index birth.
Three multivariable multinomial logistic regression
models were used to assess whether maternal age, marital
status, or race/ethnicity was related to a change in the
duration of exclusive breastfeeding for the mother’s second
child. The first model included 883 women who never
breastfed their first child, the second included 788 women
who exclusively breastfed their first child for \4 months,
and the third included 478 women who exclusively
breastfed their first child for C4 months. Referent groups
for the outcome variables in each of these three models
were women whose first two children were in the same
Matern Child Health J (2011) 15:1210–1216 1211
123
category of exclusive breastfeeding. Referent groups for
the independent factors were individuals known to have
lower rates of breastfeeding (younger, unmarried, and non-
Hispanic black women).
SUDAAN 9.0 software was used for all statistical
analyses to account for the complex sampling design. Data
were analyzed using the survey sample weights to adjust
for oversampling and underrepresentation of some groups
due to non-coverage and non-response.
Results
Of the 5,095 first-, second-, and third-born children born
to multiparous mothers in our sample, 39% were never
breastfed, whereas 39% were exclusively breastfed for
\4 months, and 22% were exclusively breastfed for
C4 months (Table 1). The median number (95% confi-
dence limits) of months of exclusive breastfeeding was 0.7
(0.6, 0.9) among those exclusively breastfed for\4 months
and was 5.0 (4.6, 5.1) among those exclusively breastfed
for C4 months. Children born to mothers who were
B25 years of age, unmarried, or NH black were less likely
to be exclusively breastfed for C4 months compared to
other children.
All subsequent results are based on the mother as the
unit of analysis. Approximately 70% of 2,149 multiparous
women repeated the duration of exclusive breastfeeding of
the first child for the second (Table 2). Fourteen percent of
mothers exclusively breastfed their first two children for
C4 months and about 2% (n = 45) switched from not
breastfeeding their first child to exclusively breastfeeding
their second child for C4 months. While approximately
60% of women with three or more children repeated the
duration of exclusive breastfeeding of the first child for the
second and third, only 13% exclusively breastfed all three
children for C4 months. Among women with three or more
children, about 20% repeated duration of breastfeeding for
the second and third child only and 11% repeated duration
for the first and second child only.
Table 3 presents adjusted odds ratios and 95% confi-
dence intervals for duration of exclusive breastfeeding for
the second child in relation to duration of exclusive
breastfeeding of the first child and maternal demographic
characteristics of the second child. Relative to mothers who
never breastfed their first child, mothers who exclusively
breastfed their first child for C4 months had significantly
greater odds (OR = 90.7, 95% CI: 45.4–181.4) of breast-
feeding the second child exclusively for C4 months after
adjustment for maternal characteristics. This large estimate
is a reflection of the odds overestimating the relative risk
due to the high prevalence of mothers repeating breast-
feeding practices for her children. In the same model, we
observed married women and older mothers were more
likely to exclusively breastfeed second children than their
counterparts even after adjustment for the duration of
exclusive breastfeeding of their first child.
Duration of exclusive breastfeeding of third children
was also highly influenced by the mother’s practice with
earlier children (Table 4). Relative to mothers who never
breastfed their second child, mothers who exclusively
breastfed their second child for C4 months had substan-
tially greater odds of exclusively breastfeeding their third
child for C4 months, adjusting for the duration of exclu-
sive breastfeeding for the first child and maternal charac-
teristics of the third child (OR = 93.2, 95% CI =
30.8–281.8). The impact on exclusive breastfeeding for
C4 months for third children was weaker for duration of
exclusive breastfeeding of first children in adjusted models
that included the duration of exclusive breastfeeding of
second children along with maternal characteristics
(OR = 6.5, 95% CI = 2.5–16.8).
Table 1 Duration of exclusive
breastfeeding by maternal
characteristics among children
of multiparous women
(n = 5,095 childrena), National
Survey of Family Growth,
2002b
a Up to three children per
mother were analyzedb Weighted row percentages
(standard errors) are presented
and may not total 100% due to
rounding
Maternal
characteristics
Never breastfed
(n = 2,116)
Exclusively breastfed
\4 months (n = 1,825)
Exclusively breastfed
C4 months (n = 1,154)
v2 P value
Total children 39.2 (1.3) 38.8 (1.3) 22.0 (1.2) –
Maternal age at birth
B25 years 48.3 (1.6) 33.9 (1.4) 17.8 (1.5)
[25 years 28.9 (1.6) 44.3 (2.0) 26.8 (1.9) \0.001
Race/ethnicity
White, non-hispanic 35.9 (1.7) 41.7 (1.8) 22.4 (1.7)
Black, non-hispanic 64.1 (2.4) 23.4 (2.0) 12.4 (1.7)
Hispanic 33.3 (1.9) 41.8 (2.1) 24.9 (2.2)
Other, non-hispanic 35.7 (6.8) 31.0 (4.9) 33.3 (4.7) \0.001
Marital status at birth
Married 30.9 (1.4) 43.6 (1.5) 25.5 (1.6)
Unmarried 57.3 (2.1) 28.2 (1.8) 14.5 (1.3) \0.001
1212 Matern Child Health J (2011) 15:1210–1216
123
Although we had little statistical power to evaluate
characteristics of mothers who changed breastfeeding
practices between the first and second child, we did observe
that among mothers who never breastfed their first child
(n = 883), mothers married at their second birth had sig-
nificantly greater odds of exclusively breastfeeding their
second child C 4 months, relative to unmarried mothers at
second birth (OR = 3.5, 95% CI: 2.0–6.2). This association
strengthened after additional adjustment for marital status at
first birth (OR = 6.2, 95% CI: 2.7–14.2). Among mothers
who exclusively breastfed their first child for \4 months
(n = 788), married women at second birth had approxi-
mately half the odds of never breastfeeding their second
child, compared with unmarried women. This association,
however, lost statistical significance after adjusting for
marital status at first birth (OR = 0.4, 95% CI: 0.2–1.1).
Among mothers who exclusively breastfed their first child
for C4 months (n = 478), we observed no significant dif-
ferences by marital status in the odds of switching from
exclusively breastfeeding the first child for C4 months to
never breastfeeding the second child or exclusively
breastfeeding the second child for\4 months. Furthermore,
we found no statistically significant evidence of maternal
age at second birth or race/ethnicity as predictors of
changing practices between the first two children, regard-
less of the exclusive breastfeeding duration of the first child.
Discussion
Our findings indicate that multiparous women tended to not
only repeat the duration of exclusive breastfeeding of
previous children with later children, but were more likely
to repeat the experience of the immediately preceding
child. In our sample, 14% and 13% of women exclusively
breastfed their first two and three children for four or more
months, respectively. Changing breastfeeding practices
between children was less common than repeating, espe-
cially changing from never breastfeeding to exclusively
breastfeeding for four or more months and vice versa.
Mothers who never breastfed their first child but exclu-
sively breastfed their second for at least 4 months were
more likely to be married at second birth than not, even
after adjusting for marital status at first birth.
Our finding that siblings typically share similar dura-
tions of exclusive breastfeeding is consistent with the
Table 2 Duration of exclusive breastfeeding for siblings among multiparous women, National Survey of Family Growth, 2002a
First | second child (N = 2,149) First | second | third child (N = 797)
Duration patterns % (s.e.) Duration patterns % (s.e.)
Repetition Repetition: all three children
NBF | NBF 30.0 (1.5) NBF | NBF | NBF 26.7 (1.8)
\4 m | \4 m 25.7 (1.3) \4 m | \4 m | \4 m 20.5 (2.2)
C4 m | C4 m 14.0 (1.0) C4 m | C4 m | C4 m 13.0 (1.6)
No repetition Repetition: 2nd and 3rd child
NBF | \4 m 7.1 (1.5) � | NBF | NBF 5.5 (1.0)
NBF | C4 m 2.4 (0.5) � | \4 m | \4 m 9.1 (3.8)
\4 m | NBF 7.8 (0.8) § | C4 m | C4 m 5.2 (1.1)
\4 m | C 4 m 5.4 (0.6)
C4 m | NBF 1.4 (0.3) Repetition: 1st and 2nd child
C4 m | \4 m 6.1 (0.7) NBF | NBF | � 4.4 (0.9)
\4 m | \4 m | � 3.8 (1.2)
C4 m | C4 m | § 2.3 (0.7)
Repetition: 1st and 3rd child
NBF | � | NBF 1.9 (0.6)
\4 m | � | \4 m 2.6 (0.7)
C4 m | § | C4 m 2.2 (0.7)
No repetition 3.0 (1.0)
NBF never breastfed; m monthsa Weighted row percentages (standard errors) are presented and may not total 100% due to rounding
�\4 or C4 months of exclusive breastfeeding
� Never breastfed or C4 months of exclusive breastfeeding
§ Never breastfed or \4 months of exclusive breastfeeding
Matern Child Health J (2011) 15:1210–1216 1213
123
Taylor study [9], which also used 2002 NSFG data but
instead assessed patterns of breastfeeding initiation. Our
results, however, are not entirely comparable and differ-
ences can be attributable to important methodological
differences between our studies in addition to the differ-
ence in outcome variables. Taylor et al. found no relation
between being married and ever having breastfed second
children among mothers who did not breastfeed their first
child, but reported significant associations with race and
education. Noting these differences, it is important to
mention that we used complete data from all multiparous
mothers while Taylor et al. restricted their sample using
different exclusion criteria. For example, in this particular
analysis they included only multiparous mothers with only
two children. In addition to differences in the analytic
samples, we adjusted for a different set of covariates in an
attempt to better control for time varying factors. Educa-
tion was not included as a covariate in our final analyses
because it was only available at time of interview and
including education did not appreciably change our
reported estimates. In our adjusted analyses, we used
covariates at the time of the index birth and therefore
marital status and maternal age varied in contrast to Taylor
et al.’s use of age at first pregnancy and marital status at
interview which could have been several years after the
index birth.
Reasons for the positive associations between marriage
and exclusive breastfeeding observed in our study may be
related to husband’s support and preference for breast-
feeding over formula-feeding [12, 13]. However, we
acknowledge that all fathers do not encourage breastfeed-
ing and that the association with marital status in our final
analysis may have been due to chance given the small
number of women who never breastfed their first child but
exclusively breastfed their second for C4 months.
In sensitivity analyses, we controlled for interpregnancy
interval to account for the spacing between children.
Breastfeeding an earlier child may affect the time of con-
ception of a later child [14] and thus may impact the in-
terpregnancy interval. Short (e.g. \18 months) and long
(e.g. C24 months) intervals have been noted to adversely
affect birth outcomes (e.g. birth weight) [15, 16], which in
turn could affect breastfeeding practices [17, 18]. Estimates
before and after adjustment for interpregnancy interval in
multivariable models were comparable, suggesting that the
observed associations did not act through child spacing
(data not shown).
Strengths of this study include our use of survey data
that is representative of ethnically diverse women
throughout the nation and our adjustment for covariates for
Table 3 Adjusted odds ratios (OR) and 95% confidence intervals
(CI) for exclusively breastfeeding the second child for \4 months or
C4 months compared to no breastfeedinga by selected characteristics
(n = 2,149 women), National Survey of Family Growth, 2002
Selected characteristics 2nd child
EBF \ 4 months
(n = 768)
EBF C 4 months
(n = 477)
ORb 95% CIb ORb 95% CIb
First child
Never breastfed 1.0 Referent 1.0 Referent
EBF \ 4 months 12.1 7.0, 21.1 7.2 4.0, 12.9
EBF C 4 months 14.0 7.7, 25.4 90.7 45.4, 181.4
Maternal age at 2nd birth
B25 years 1.0 Referent 1.0 Referent
[25 years 1.7 1.1, 2.6 1.6 1.0, 2.7
Marital status at 2nd birth
Unmarried 1.0 Referent 1.0 Referent
Married 1.5 1.0, 2.3 2.1 1.4, 3.4
Maternal race/ethnicity
NH white 1.3 0.8, 2.0 1.2 0.7, 2.0
NH black 1.0 Referent 1.0 Referent
Hispanic 1.3 0.9, 2.0 1.4 0.8, 2.6
NH other 0.7 0.3, 1.6 1.1 0.4, 2.8
EBF exclusively breastfeda The referent group, for the outcome, duration of exclusive breast-
feeding for the 2nd child (n = 904)b Model includes breastfeeding status for the first child, maternal age
at 2nd birth, marital status at 2nd birth, race/ethnicity
Table 4 Adjusted odds ratios (OR) and 95% confidence intervals
(CI) for exclusively breastfeeding the third child for \4 months or
C4 months compared to no breastfeedinga by breastfeeding duration
of previous children (n = 797 women), National Survey of Family
Growth, 2002
Exclusive breastfeeding
duration of previous children
3rd child
EBF \ 4 months
(n = 269)
EBF C 4 months
(n = 199)
ORb 95% CIb ORb 95% CIb
First child
Never breastfed 1.0 Referent 1.0 Referent
EBF \ 4 months 2.1 0.8, 5.4 2.0 0.8, 5.0
EBF C 4 months 1.6 0.6, 4.6 6.5 2.5, 16.8
Second child
Never breastfed 1.0 Referent 1.0 Referent
EBF \ 4 months 21.4 8.7, 52.9 5.2 1.9, 14.4
EBF C 4 months 13.4 4.6, 39.2 93.2 30.8, 281.8
EBF exclusively breastfeda The referent group, for the outcome, duration of exclusive breast-
feeding for the 3rd child (n = 329)b Adjusted for maternal age at 3rd birth, marital status at 3rd birth,
race/ethnicity, and duration of exclusive breastfeeding for the other
(first or second) child
1214 Matern Child Health J (2011) 15:1210–1216
123
relevant time periods. We also expanded upon previous
work by examining duration of exclusive breastfeeding,
which has major maternal and child health benefits when
adequately practiced and is highly recommended beyond
breastfeeding initiation [19, 20].
Our study is not without limitations. We were unable to
distinguish different types of supplemental foods or to
control for potentially important covariates assessed at the
time of birth, such as education or poverty. In sensitivity
analyses, adjustment for these variables, which were
assessed at interview, yielded little change in effect esti-
mates (data not shown). Furthermore, we did not have
sufficient statistical power to analyze associations for
breastfeeding duration of sibling sets of four or more
children.
In this study, respondents reported the breastfeeding
experiences of children who were less than 19 years of age.
Maternal recall of breastfeeding initiation has been shown to
be valid [21] and therefore any misclassification of never
having breastfed should be minimal. However, recall of the
age at supplementation (introduction of foods and liquids
other than breast milk) has been shown to be less satisfactory
[21] and to have a tendency to be somewhat overestimated
among short-term breastfeeders [21, 22]. Categorizing
duration of exclusive breastfeeding into three groups (never
breastfed, \4 months, and C4 months) may have limited
this potential misclassification bias. Furthermore, given the
widespread acceptance and promotion of adequate breast-
feeding throughout the nation, mothers may have overesti-
mated lengths of breastfeeding for all of their children [21,
22]. This misclassification may have generated some over-
estimation of exclusive breastfeeding for C4 months.
Nonetheless, our findings were consistent with those from
studies with a prospective cohort study design [6, 8]. Lastly,
some mothers may have confused the breastfeeding experi-
ences of their children due to the passage of time, especially
for older children. Since the respondents with children at
least 19 years of age were excluded from our study, this
recall bias may have been lessened.
Overall, we found positive associations between the
duration of exclusive breastfeeding of previous children,
especially of immediately preceding children, and that of
subsequent children. These findings are consistent with
previous reports that suggest the breastfeeding experiences
of primiparous women play an important role in deter-
mining whether and how they will breastfeed later children,
making them an important group for targeted intervention
[9]. Future studies should examine these associations pro-
spectively to avoid potential recall bias, measure other
potentially important predictors such as maternal education
and poverty at each birth, and identify reasons why parous
women switch to more or less favorable breastfeeding
practices.
Disclaimer The findings and conclusions in this report are those of
the authors and do not necessarily represent the official position of the
Centers for Disease Control and Prevention, the Department of Health
and Human Services, or the US Public Health Service.
References
1. Gartner, L. M., Morton, J., Lawrence, R. A., et al. (2005).
Breastfeeding and the use of human milk. Pediatrics, 115,
496–506.
2. Thygarajan, A., & Burks, A. W. (2008). American Academy of
Pediatrics recommendations on the effects of early nutritional
interventions on the development of atopic disease. CurrentOpinion in Pediatrics, 20, 698–702.
3. Anderson, J., Malley, K., & Snell, R. (2009). Is 6 months still the
best for exclusive breastfeeding and introduction of solids? A
literature review with consideration to the risk of the develop-
ment of allergies. Breastfeed Rev, 17, 23–31.
4. Centers for Disease Control and Prevention. (2010). Breastfeed-ing among US children born 1999–2006. http://www.cdc.
gov/BREASTFEEDING/DATA/NIS_data/index.htm. [Date of
Access: January, 25, 2010].
5. Thulier, D., & Mercer, J. (2009). Variables associated with
breastfeeding duration. Journal of Obstetric, Gynecologic, andNeonatal Nursing, 38, 259–268.
6. Hornell, A., Aarts, C., Kylberg, E., et al. (1999). Breastfeeding
patterns in exclusively breastfed infants: a longitudinal prospec-
tive study in Uppsala, Sweden. Acta Paediatrica, 88, 203–211.
7. Nagy, E., Orvos, H., Pal, A., et al. (2001). Breastfeeding duration
and previous breastfeeding experience. Acta Paediatrica, 90,
51–56.
8. Kruse, L., Denk, C. E., Feldman-Winter, L., et al. (2006). Lon-
gitudinal patterns of breastfeeding initiation. Maternal and ChildHealth Journal, 10, 13–18.
9. Taylor, J. S., Geller, L., Risica, P. M., et al. (2008). Birth order
and breastfeeding initiation: Results of a national survey.
Breastfeeding Medicine, 3, 20–27.
10. Groves, R. M., Benson, G., Mosher, W. D., et al. (2005). Plan and
operation of cycle 6 of the national survey of family growth. Vitaland Health Statistics, 1, 1–86.
11. Hosmer, D., & Lemeshow, S. (2000). Applied logistic regression.
New York: John Wiley & Sons.
12. Jones, D. A., West, R. R., & Newcombe, R. G. (1986). Maternal
characteristics associated with the duration of breast-feeding.
Midwifery, 2, 141–146.
13. Stremler, J., & Lovera, D. (2004). Insight from a breastfeeding
peer support pilot program for husbands and fathers of Texas
WIC participants. Journal of Human Lactation, 20, 417–422.
14. Brown, R. E. (1982). Breast-feeding and family planning: A
review of the relationships between breast-feeding and family
planning. American Journal of Clinical Nutrition, 35, 162–171.
15. Norton, M. (2005). New evidence on birth spacing: Promising
findings for improving newborn, infant, child, and maternal
health. International Journal of Gynaecology and Obstetrics,89(Suppl 1), S1–S6.
16. Zhu, B. P., Rolfs, R. T., Nangle, B. E., et al. (1999). Effect of the
interval between pregnancies on perinatal outcomes. New Eng-land Journal of Medicine, 340, 589–594.
17. Dougherty, D., & Luther, M. (2008). Birth to breast–a feeding
care map for the NICU: Helping the extremely low birth weight
infant navigate the course. Neonatal Network, 27, 371–377.
18. Rodriguez, N. A., Miracle, D. J., & Meier, P. P. (2005). Sharing
the science on human milk feedings with mothers of very-
Matern Child Health J (2011) 15:1210–1216 1215
123
low-birth-weight infants. Journal of Obstetric, Gynecologic, andNeonatal Nursing, 34, 109–119.
19. Black, R. E., Allen, L. H., Bhutta, Z. A., et al. (2008). Maternal
and child undernutrition: Global and regional exposures and
health consequences. Lancet, 371, 243–260.
20. Fewtrell, M. S., Morgan, J. B., Duggan, C., et al. (2007). Optimal
duration of exclusive breastfeeding: What is the evidence to
support current recommendations? American Journal of ClinicalNutrition, 85, 635S–638S.
21. Li, R., Scanlon, K. S., & Serdula, M. K. (2005). The validity and
reliability of maternal recall of breastfeeding practice. NutritionReviews, 63, 103–110.
22. Gillespie, B., d’Arcy, H., Schwartz, K., et al. (2006). Recall of
age of weaning and other breastfeeding variables. InternationalBreastfeeding Journal, 1, 4.
1216 Matern Child Health J (2011) 15:1210–1216
123
Copyright of Maternal & Child Health Journal is the property of Springer Science & Business Media B.V. and
its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's
express written permission. However, users may print, download, or email articles for individual use.