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Dept. of Family Medicine and Population Health
2016
The Interrelationship Between Repeat Cesarean
Section, Smoking Status, and Breastfeeding
Duration
Jordyn T. Wallenborn
Virginia Commonwealth University, [email protected]
Saba W. Masho
Virginia Commonwealth University
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BREASTFEEDING MEDICINE
Volume 11, Number 9, 2016
ª Mary Ann Liebert, Inc.
DOI: 10.1089/bfm.2015.0165
The Interrelationship Between Repeat Cesarean Section,
Smoking Status, and Breastfeeding Duration
Jordyn T. Wallenborn and Saba W. Masho
Abstract
Background: The rate of breastfeeding duration is staggeringly low with only one-quarter of infants in the
United States being exclusively breastfed at 6 months. Maternal smoking and mode of delivery have been
identified as independent risk factors for shorter breastfeeding duration. This study aims to evaluate the effect of
repeat cesarean delivery on breastfeeding duration, taking into account smoking status.
Materials and Methods: Data from the U.S. population-based Pregnancy Risk Assessment Monitoring System
survey, 2004–2011, were analyzed. Women who delivered a live singleton baby, had a previous birth through
cesarean delivery, and provided mode of delivery and breastfeeding information were included in the analysis.
Multinomial logistic regression models provided crude and adjusted odds ratios (AORs) and 95% confidence
intervals (CIs). All models were stratified by smoking status.
Results: Among smokers, women who had repeat cesarean section had a 2-fold higher odds of never breastfeeding
(AOR = 2.43, 95% CI = 1.38–4.29) and a 4-fold higher odds of breastfeeding 8 weeks or less (AOR = 4.11, 95%
CI = 2.08–8.11) compared with women who gave birth vaginally after cesarean section. Among nonsmokers, the
odds of never breastfeeding and breastfeeding 8 weeks or less were 2.4 times (AOR = 2.36, 95% CI = 1.84–3.03)
and 1.4 times (AOR = 1.44, 95% CI = 1.15–1.80) higher in women who had repeat cesarean section compared with
women who had vaginal birth after cesarean section, respectively.
Conclusions: Among women who smoke during pregnancy, the results suggest that repeat cesarean delivery
negatively affects breastfeeding duration. Interventions are needed for mothers who smoke during pregnancy
and undergo repeat cesarean delivery.
Keywords: mode of delivery, breastfeeding, smoking, PRAMS, pregnancy
Introduction
T
he United States has one of the lowest breastfeeding
rates in the world.1 In 2014, only 19% of mothers exclusively breastfed their infants for at least 6 months. The
American Academy of Pediatrics recommends that mothers
exclusively breastfeed for 6 months, followed by 6 months of
continued breastfeeding with the introduction of solid food.2
Failure to breastfeed may result in a host of deleterious outcomes for both mother and child.3–7
One major risk factor associated with the low breastfeeding rate is cesarean section (cesarean delivery).8–10 In fact, a
recent systematic review by Prior et al. reported lower rates
of breastfeeding among women with cesarean delivery.9
Additionally, women who had a vaginal delivery reported
higher breastfeeding rates after discharge at 7 days, 3 months,
and 6 months compared with women who had an elective or
emergency cesarean delivery.11
In addition to cesarean delivery demonstrating a differential
effect on breastfeeding duration compared with a vaginal delivery, research has also demonstrated that vaginal delivery has a
shorter mean time to breastfeeding initiation compared with
cesarean delivery.8,9 However, it is unknown whether the differential effect of breastfeeding outcomes between cesarean
delivery and vaginal delivery continues after a primary cesarean
delivery. It is possible that women who choose vaginal birth after
cesarean (VBAC) may have healthy behaviors and healthier
choices. We hypothesize that women who decide to have VBAC
may have higher level of intention and self-efficacy to breastfeed
and engage in positive health behaviors.
In addition to cesarean delivery, smoking during pregnancy
has consistently demonstrated a significant association with
breastfeeding practices.12–14 In a longitudinal cohort study,
women who smoked during pregnancy were more likely to
not breastfeed at 6 months compared with nonsmokers, even
after adjusting for maternal age, education, and breastfeeding
Division of Epidemiology, Department of Family Medicine and Population Health, School of Medicine, Virginia Commonwealth
University, Richmond, Virginia.
440
REPEAT CESAREAN DELIVERY, SMOKING, AND BREASTFEEDING
441
Table 1. Distribution of Maternal Characteristics by Mode of Delivery
Potential confounders
Age (years)
£19
20–24
25–29
30–34
‡35
Education (years)
Did not finish high school (<12 years)
High school diploma (12 years)
College or higher (>12 years)
Race/ethnicity
White, non-Hispanic
Black, non-Hispanic
Other, non-Hispanic
Hispanic
Not married
Income
<$20,000
$20,000–$34,999
$35,000–$49,000
‡$50,000
Rural
Insurance
Private
Medicaid
None
Other
Multiplea
Adequacy of prenatal care utilization
Inadequate
Intermediate
Adequate
Adequate plus
Breastfeeding duration
Never breastfed
Breastfed £8 weeks
Breastfed >8 weeks
Healthcare worker did not talk about breastfeeding
WIC recipient
Smoked during pregnancy
Prepregnancy multivitamin use
None
1–3 Days/week
4–6 Days/week
Every day
Prepregnancy BMI
Underweight
Normal
Overweight
Obese
Pregnancy intention
Unwanted
Mistimed
Intended
Total weighted% VBAC weighted%
Unweighted
Unweighted
(n = 34,532)
(n = 3,365)
Repeat C-section
weighted%
Unweighted
Chi-square
(n = 31,167)
p-value
0.4747
2.0
16.1
27.1
31.3
23.5
1.4
15.7
28.4
31.2
23.3
2.0
16.2
27.0
31.3
23.5
16.4
26.9
56.7
20.3
24.1
55.6
16.0
27.2
56.8
59.8
14.9
6.6
18.7
29.6
56.8
13.2
7.7
22.3
28.4
60.2
15.1
6.4
18.3
29.8
32.4
17.0
10.4
40.1
27.7
32.4
18.0
11.5
38.1
22.1
32.5
16.9
10.3
40.3
28.3
45.4
34.0
3.3
2.0
15.3
43.7
34.7
5.4
2.7
13.5
45.6
34.0
3.0
1.9
15.5
11.6
12.4
45.2
30.8
16.2
16.7
41.5
25.6
11.1
11.9
45.7
31.3
25.0
22.1
52.9
20.1
42.8
13.1
15.7
16.1
68.3
20.3
42.6
13.9
26.0
22.8
51.2
20.0
42.9
13.1
54.6
9.0
6.4
29.9
50.4
10.8
6.9
31.9
55.1
8.8
6.3
29.7
2.6
40.4
27.0
29.9
3.7
50.9
26.4
18.9
2.5
39.3
27.0
31.2
12.7
44.7
42.6
12.8
41.0
46.2
12.7
45.1
42.2
0.0003
0.0002
0.3219
0.3255
0.0008
0.0002
<0.0001
<0.0001
0.8377
0.8798
0.534
0.0043
<0.0001
0.0128
(continued)
442
WALLENBORN AND MASHO
Table 1. (Continued)
Potential confounders
Total weighted% VBAC weighted%
Unweighted
Unweighted
(n = 34,532)
(n = 3,365)
Preterm birth (weeks)
Term (37+)
Preterm (34–36)
Very preterm (28–33)
Extremely preterm (£27)
Birth weight
Normal birth weight
Low birth weight
Very low birth weight
Intimate partner violence before or during pregnancy
Hospitalized during pregnancy
Length of hospital stay after birth
No hospital stay
1–2 Nights
3–4 Nights
5+ Nights
Repeat C-section
weighted%
Unweighted
Chi-square
(n = 31,167)
p-value
0.7075
91.0
6.9
1.7
0.3
91.3
6.6
1.7
0.4
91.0
7.0
1.7
0.3
94.2
4.9
0.9
8.6
13.1
94.2
4.9
1.0
8.4
10.3
94.2
4.9
0.9
8.6
13.4
0.4
27.0
61.9
10.7
2.6
51.5
38.9
7.0
0.2
24.6
64.1
11.0
0.9439
0.8602
0.0094
<0.0001
All analyses were performed on weighted data.
a
Multiple indicates two or more of the following insurances: private, Medicaid, or other.
BMI, body mass index; VBAC, vaginal birth after cesarean.
intention.10 Another longitudinal study using Kaplan–Meier
survival analysis related shorter duration of breastfeeding to
women who smoked during pregnancy.12 This study reported a
median breastfeeding duration of 28 weeks for nonsmokers
and 11 weeks for smokers.
Although there is limited physiological evidence surrounding the effect of smoking on breastfeeding,15 psychosocial factors may play a role. Mothers who smoke may
believe smoking while breastfeeding is harmful to the baby,16
which may be an explanation for the differential effect observed between smokers and nonsmokers. In addition to the
effect of smoking on breastfeeding, there may be a differential
effect between smoking status and the decision to have VBAC.
For example, a retrospective analysis of singleton pregnancies
found that smokers had an increased risk of operative delivery.17 Furthermore, it is possible that nonsmokers may have
higher self-efficacy to seek and have VBAC due to the numerous benefits associated with VBAC.18
Considering the strong independent correlation between mode
of delivery, smoking status, and breastfeeding duration, understanding the interrelationship between breastfeeding duration
and repeat cesarean delivery among smokers and nonsmokers is
essential. To date, extant literature is focused on breastfeeding
initiation or infant to breast contact and primary cesarean delivery8,19–21; however, little is known about the association
between repeat cesarean delivery and breastfeeding duration.
Furthermore, the interaction between VBAC and smoking is
poorly investigated. Therefore, this study aims to evaluate the
relationship of repeat cesarean delivery and breastfeeding duration, taking into account the effect of smoking status.
Materials and Methods
Data from Phase 5 (2004–2008) and Phase 6 (2009–2011)
of the Pregnancy Risk Assessment Monitoring System
(PRAMS) were analyzed. PRAMS is a U.S. population-based
survey funded by the Centers for Disease Control and Prevention (CDC) that identifies maternal experiences and behaviors
before and during pregnancy and the early months after birth.
The PRAMS sample includes women identified through state
birth certificate records as recently having a live birth. Women
selected are typically interviewed 2–6 months after delivery and
are contacted by mail or phone. Each participating state samples
between 1,300 and 3,400 women per year with a minimum
overall response rate of 65%. To ensure a representative sample,
higher risk groups (i.e., mothers of low birth weight infants) are
sampled at a higher rate.22 A detailed description of PRAMS is
published elsewhere.23
The dataset included 319,689 women who had a live singleton birth. Women were excluded from analysis if they did
not have a previous live birth, whose infant was not alive,
who gave birth to more than one child, who did not report
duration of breastfeeding, and did not have a prior cesarean
delivery or the mode of delivery was missing. This yielded a
total of 34,532 women who had a prior cesarean delivery and
delivered a live singleton baby.
The exposure variable, mode of delivery, was determined
using the survey item, ‘‘How was your new baby delivered,
vaginally or by cesarean delivery?’’ Based on this question,
the variable was coded as repeat cesarean delivery and
VBAC. The outcome variable, breastfeeding duration, was
determined using the survey question, ‘‘How many weeks or
months did you breastfeed or pump milk to feed your baby?’’
The data were then categorized as never breastfed, breastfed
less than 1 to 8 weeks, or breastfed more than 8 weeks.
Breastfed less than 1 to 8 weeks does not include never
breastfed. The 8-week cutoff was determined by the minimum time elapsed between birth and interview. Smoking
during the last 3 months of pregnancy was based on the
survey item, ‘‘In the last 3 months of your pregnancy, how
many cigarettes did you smoke on an average day?’’ Smoking was then categorized as smoker and nonsmoker.
REPEAT CESAREAN DELIVERY, SMOKING, AND BREASTFEEDING
443
Table 2. Factors Associated with Breastfeeding Duration
Odds ratio (95% CI)
Factors
Age (years)
£19
20–24
25–29
30–34
‡35
Education (years)
Did not finish high school (<12 years)
High school diploma (12 years)
College or higher (>12 years)
Race/ethnicity
White, non-Hispanic
Black, non-Hispanic
Other, non-Hispanic
Hispanic
Not married (vs. married)
Income
<$20,000
$20,000–$34,999
$35,000–$49,000
‡$50,000
Rural (vs. urban)
Insurance
Private
Medicaid
None
Other
Multiplea
Adequacy of prenatal care utilization
Inadequate
Intermediate
Adequate
Adequate plus
Healthcare worker did not talk about breastfeeding (vs. yes)
WIC recipient (vs. not)
Smoked during pregnancy (vs. no smoking)
Prepregnancy multivitamin use
None
1–3 Days/week
4–6 Days/week
Everyday
Prepregnancy BMI
Underweight
Normal
Overweight
Obese
Pregnancy intention
Unwanted
Mistimed
Intended
Repeat C-section (vs. VBAC)
Preterm birth (weeks)
Term (37+)
Preterm (34–36)
Very preterm (28–33)
Extremely preterm (£27)
Never breastfed vs.
breastfed > 8 weeks
Breastfed £ 8 weeks vs.
breastfed > 8 weeks
1.72 (1.19–2.50)
1.00
0.48 (0.42–0.55)
0.35 (0.31–0.40)
0.29 (0.25–0.34)
1.36 (0.92–2.02)
1.00
0.63 (0.54–0.72)
0.40 (0.35–0.46)
0.38 (0.33–0.44)
2.58 (2.28–2.91)
2.80 (2.54–3.09)
1.0
1.50 (1.31–1.71)
1.83 (1.65–2.02)
1.0
1.0
1.90 (1.70–2.12)
0.38 (0.31–0.45)
0.44 (0.38–0.51)
3.07 (2.79–3.37)
1.0
1.49 (1.32–1.69)
0.66 (0.57–0.78)
0.88 (0.77–0.99)
1.90 (1.72–2.10)
3.02 (2.72–3.37)
1.93 (1.69–2.19)
1.38 (1.18–1.60)
1.0
1.48 (1.28–1.71)
1.94 (1.74–2.17)
1.59 (1.40–1.81)
1.20 (1.03–1.39)
1.0
1.24 (1.08–1.44)
1.00
2.64 (2.39–2.91)
0.49 (0.36–0.66)
0.92 (0.63–1.34)
1.22 (1.07–1.38)
1.00
1.79 (1.62–1.98)
0.77 (0.57–1.03)
0.83 (0.56–1.25)
1.26 (1.11–1.42)
1.87 (1.62–2.16)
1.01 (0.88–1.17)
1.00
1.33 (1.20–1.47)
0.81 (0.73–0.89)
2.19 (2.00–2.38)
4.98 (4.27–5.80)
1.10 (0.94–1.30)
0.94 (0.82–1.09)
1.00
1.21 (1.09–1.34)
0.65 (0.58–0.73)
1.70 (1.55–1.86)
2.89 (2.45–3.41)
2.43 (2.20–2.68)
1.33 (1.12–1.57)
0.68 (0.55–0.85)
1.0
1.79 (1.62–1.98)
1.27 (1.08–1.50)
0.80 (0.66–0.97)
1.0
1.44 (1.10–1.89)
1.0
1.40 (1.26–1.57)
2.76 (2.42–3.14)
0.99 (0.73–1.34)
1.0
1.20 (1.08–1.35)
1.83 (1.64–2.04)
1.23 (1.14–1.34)
1.32 (1.20–1.44)
1.0
2.21 (1.88–2.60)
1.71 (1.48–1.97)
1.35 (1.23–1.49)
1.0
1.89 (1.62–2.21)
1.0
1.26 (1.08–1.47)
0.96 (0.78–1.18)
0.70 (0.50–0.99)
1.0
1.31 (1.12–1.53)
1.32 (1.10–1.58)
0.83 (0.60–1.14)
(continued)
444
WALLENBORN AND MASHO
Table 2. (Continued)
Odds ratio (95% CI)
Factors
Birth weight
Normal birth weight
Low birth weight
Very low birth weight
Intimate partner violence before or during pregnancy (vs. none)
Hospitalized during pregnancy (vs. not)
Length of hospital stay after birth
No hospital stay
1–2 Nights
3–4 Nights
5+ Nights
Never breastfed vs.
breastfed > 8 weeks
Breastfed £ 8 weeks vs.
breastfed > 8 weeks
1.0
1.49 (1.35–1.65)
1.02 (0.80–1.31)
1.52 (1.26–1.83)
1.43 (1.24–1.66)
1.0
1.41 (1.27–1.57)
1.26 (1.01–1.57)
1.76 (1.46–2.13)
1.50 (1.29–1.75)
1.0
1.86 (1.03–3.34)
1.53 (0.86–2.75)
1.91 (1.06–3.47)
1.0
3.33 (1.65–6.71)
3.26 (1.62–6.55)
3.53 (1.74–7.16)
Bold estimates significant.
a
Multiple indicates two or more of the following insurances: private, Medicaid, or other.
CI, confidence interval.
Based on previous literature, potential confounders
were examined.24–26 Covariates included maternal age (<20;
20–24; 25–29; 30–34; 35+ years), maternal race (nonHispanic black; non-Hispanic white; Hispanic; non-Hispanic
other), maternal education (<12 years; 12 years/H.S. diploma;
>12 years), marital status (married; other), income (less than
$20,000; $20,000–$34,999; $35,000–$49,999; $50,000+),
rural/urban status (rural; urban), insurance (private; Medicaid; none; other; multiple), adequacy of prenatal care (inadequate; intermediate; adequate; adequate plus), healthcare
worker discussing breastfeeding (yes; no), WIC recipient
(yes; no), multivitamin use (did not take multivitamins; one to
three times per week; four to six times per week; every day),
prepregnancy body–mass index (underweight [<18.5]; normal [18.5–24.9], overweight [25–29.9], obese [>30]), pregnancy intention (unwanted; mistimed; intended), preterm
birth (term [37+ weeks]; preterm [34–36 weeks]; very preterm [28–33 weeks]; extremely preterm [<28 weeks]), birth
weight (normal; low birth weight; very low birth weight),
hospitalization during pregnancy (yes; no), abuse during
pregnancy or abuse 12 months before pregnancy (yes; no),
and length of hospital stay after birth (no hospital stay; 1–2
nights; 3–4 nights; 5+ nights).
Descriptive analysis was conducted to examine the distribution of the study population. Odds ratios (ORs) and 95%
confidence intervals (CIs) were calculated using survey logistic analysis to examine associations. All analyses were
performed using survey weights; therefore, the results are
weighted. The effect of confounders was assessed using the
10% change in estimate methodology.27 Confounders that
showed at least a 10% change in the crude estimate were
retained in the parsimonious adjusted model. Based on previous literature, smoking status was shown to produce a
differential effect on breastfeeding outcomes.12–14 In fact, a
recent study by Vurbic et al. reported an interaction between
smoking and breastfeeding outcomes ( p < 0.001).28 However, no statistically significant interaction between smoking
and breastfeeding was observed in the current study ( p =
0.20). Based on findings from previous research12–14 and the
studies’ a priori hypothesis aimed to assess the interrelationship between VBAC, smoking, and breastfeeding, all
analyses were stratified by smoking status. Data were analyzed using SAS version 9.4 statistical software. This study
received institutional review board approval from Virginia
Commonwealth University and the CDC.
Results
Majority of the study population were married (70.4%),
25–34 years old (58.4%), non-Hispanic white (59.8%),
completed a college degree (56.7%), and reported a household income of less than $50K (59.9%). Over half (53.0%) of
the women breastfed for greater than 8 weeks, over a fifth
(22.1%) breastfed for 8 weeks or less, and a quarter (25.0%)
never breastfed (Table 1). Women who never breastfed were
highest among women less than 20 years old (46.4%), nonHispanic black (37.4%), Medicaid recipients (35.0%), and
women who smoked during pregnancy (50.3%). In contrast,
rates of breastfeeding for 8 weeks or less were highest among
women who were obese before pregnancy (26.7%) and had a
high school diploma (25.2%). Last, women who were older
than 34 years (62.2%), had a college degree (61.1%), were
non-Hispanic other (68.0%), and had no hospital stay after
birth (70.6%) had the highest rates of breastfeeding more than
8 weeks. Factors associated with breastfeeding duration can
be found in Table 2.
The unadjusted analysis showed a statistically significant
association between mode of delivery and breastfeeding
duration by smoking status. Compared with women who gave
birth by VBAC, women who smoked during the last 3 months
of pregnancy and gave birth by repeat cesarean delivery were
more likely to never breastfeed (crude odds ratio [COR] =
2.03; 95% CI = 1.23–3.34) and breastfeed 8 weeks or less
(2.99; 95% CI = 1.64–5.48). Among women who did not
smoke during the last 3 months of pregnancy, women who
gave birth by repeat cesarean delivery were more likely to
never breastfeed (COR = 2.37; 95% CI = 1.89–2.98) and
breastfeed 8 weeks or less (COR = 1.52; 95% CI = 1.24–1.87)
compared with women who gave birth by VBAC (Table 3).
After adjusting for mode of delivery, length of hospital
stay after birth, marital status, and prenatal care adequacy, the
estimate among women who smoked during pregnancy
REPEAT CESAREAN DELIVERY, SMOKING, AND BREASTFEEDING
445
Table 3. Association Between Mode of Delivery and Breastfeeding Duration Stratified by Smoking
Parsimonious modela
AOR (95% CI)
Unadjusted COR (95% CI)
Mode of delivery
Never breastfed vs.
breastfed > 8 weeks
Breastfed £ 8 weeksb vs.
breastfed > 8 weeks
Smoked during last 3 months of pregnancy
Repeat C-section
2.03 (1.23–3.34)
2.99 (1.64–5.48)
VBAC
1.00
1.00
Did not smoke during last 3 months of pregnancy
Repeat C-section
2.37 (1.89–2.98)
1.52 (1.24–1.87)
VBAC
1.00
1.00
Never breastfed vs.
breastfed > 8 weeks
Breastfed £ 8 weeksb vs.
breastfed > 8 weeks
2.43 (1.38–4.29)
1.00
4.11 (2.08–8.11)
1.00
2.36 (1.84–3.03)
1.00
1.44 (1.15–1.80)
1.00
Bold signifies significance.
The crude analysis used 24,229 observations and the parsimonious final model used 22,499 observations.
a
Parsimonious controlling for mode of delivery, marital status, prenatal care adequacy, and length of hospital stay after delivery.
b
Breastfed £8 weeks does not include never breastfed.
AOR, adjusted odds ratio; COR, crude odds ratio.
accentuated. Among women who smoked during the last 3
months of pregnancy, women who had a repeat cesarean
delivery were 2.4 times as likely to never breastfeed (adjusted
odds ratio [AOR] = 2.43; 95% CI = 1.38–4.29) and 4.1 times
as likely to breastfeed 8 weeks or less (AOR = 4.11; 95%
CI = 2.08–8.11) compared with women who gave birth by
VBAC (Table 3). In contrast, women who did not smoke
during the last 3 months of pregnancy and had a repeat cesarean delivery were 2.4 times as likely to never breastfeed
(AOR = 2.36; 95% CI = 1.84–3.03) and 1.4 times as likely to
breastfeed 8 weeks or less compared with women who gave
birth by VBAC.
Discussion
The current study identified smoking during the last 3
months of pregnancy to be an important effect modifier in the
relationship between repeat cesarean delivery and breastfeeding duration. Women who gave birth by repeat cesarean
delivery and reported smoking during the last 3 months of
pregnancy had a higher likelihood of never breastfeeding and
breastfeeding 8 weeks or less, whereas women who reported
not smoking during the last 3 months of pregnancy showed a
weaker association with never breastfeeding and breastfeeding 8 weeks or less.
To the authors’ knowledge, this is the first study to evaluate
the association between breastfeeding duration and mode of
delivery preceded by a prior cesarean delivery. The findings
in this study demonstrated a differing relationship between
mode of delivery and breastfeeding duration by smoking
status. Although no prior research (to the authors’ knowledge) was available to compare with the current study, previous literature had examined the independent effect of mode
of delivery and smoking on breastfeeding. For instance, a
study using the 2005 PRAMS Missouri data found that women were more likely to never breastfeed if they reported
being a heavy smoker, light smoker, or quit smoking during
pregnancy compared with nonsmokers.13 Similarly, a systematic review and meta-analysis by Prior et al. reported
lower rates of early breastfeeding among women who had a
cesarean delivery (pooled OR: 0.57; 95% CI: 0.50, 0.64;
p < 0.00001).9 Findings from the current study support these
conclusions, but uncovered the differential effect of repeat
cesarean delivery by smoking status.
Results from the current study could be partially explained
by an overall lower motivation to breastfeed among women
who smoke during pregnancy. A meta-analysis exploring
smoking during pregnancy and breastfeeding reported that
women who smoked were less motivated to breastfeed and
less likely to initiate breastfeeding.15 A plausible physiological explanation hypothesized for the lack of breastfeeding among smokers is the differential milk production
between smokers and nonsmokers. For instance, a study by
Vio et al. reported a negative relationship between milk
production and smoking.29 The same study further stated that
nicotine could cause a malfunction in milk production by
blocking prolactin.29 Fears surrounding smoking during
breastfeeding may also impact breastfeeding behaviors.
Specifically, mothers who smoke while breastfeeding could
view this as potentially harmful to the baby,30,31 causing
mothers to prematurely wean their child. Furthermore, women who smoke and have problems breastfeeding may be
unwilling to seek assistance from health professionals for fear
of being stigmatized.17
The current study found (1) the odds of never breastfeeding and breastfeeding 8 weeks or less were higher among
women who had repeat cesarean delivery and smoked during
pregnancy and (2) a significant association between repeat
cesarean delivery and breastfeeding duration. These differences in breastfeeding duration by mode of delivery may also
be explained by physiological pathways. Women who give
birth by cesarean delivery are more likely to have maternal
illness, which could result in reduced breastfeeding success.9
Additionally, delayed onset of lactation, disruption of
mother–infant interaction, and problems with infant suckling
may negatively affect breastfeeding practices.9
Findings from the study can be generalized to mothers
residing in participating PRAMS states in the United States
who had a live birth preceded by a prior cesarean delivery.
Results from the current study contribute to existing literature
on mode of delivery, smoking status, and subsequent effects on breastfeeding practices. Specifically, the findings of
this study demonstrated differing breastfeeding practices
by smoking status during the last 3 months of pregnancy.
446
Despite the strengths, this study has a number of limitations.
Differential recall bias could underestimate or overestimate
the association for never breastfeeding and breastfeeding
8 weeks or less; however, due to the short interval between birth and completing the survey, recall bias would be
reduced. Social desirability bias may influence mothers to
underreport smoking during the last 3 months of pregnancy,
which could bias the estimate toward the null. Additionally,
potential factors such as spousal attitude toward breastfeeding, intention to breastfeed, trial of labor after cesarean delivery (failed VBAC), and illnesses that would preclude
women from breastfeeding were not available in the dataset
and may have affected the effect size. Because we did not
have information on trial of labor (failed VBAC), women
who failed VBAC were classified as repeat cesarean delivery,
which could lead to misclassification and underestimate the
effect size. Due to a high percentage of missing observations,
urban/rural status and hospitalization during pregnancy could
not be included in the final model despite evidence of confounding. Moreover, because of the small number of women
who smoke during the last 3 months of pregnancy, the 95%
CIs are wide and future studies with a larger sample size are
warranted. Last, due to the cross-sectional nature of the study,
causal relationships cannot be determined.
Conclusions
This study demonstrated an interrelationship between
mode of delivery, smoking status during pregnancy, and
breastfeeding duration among women with a prior cesarean
delivery. Specifically, giving birth by repeat cesarean delivery among those who smoke during pregnancy is associated
with shorter breastfeeding duration. While the results persisted for those who had a repeat cesarean delivery, but did
not smoke, the strength of association diminished. Because 1
in 10 women report smoking during the last 3 months of
pregnancy,32 healthcare professionals who give postpartum
care should be familiar with the implications of repeat cesarean delivery and smoking during pregnancy on breastfeeding practices. The authors recommend efforts to increase
VBAC rates and provide counseling services to smoking
mothers in medical institutions across the United States to
help increase breastfeeding success. Further research is
warranted on the effect of trial of labor after cesarean delivery
and breastfeeding outcomes.
Acknowledgments
The authors would like to acknowledge the PRAMS Working Group: Alabama—Izza Afgan, MPH; Alaska—Kathy
Perham-Hester, MS, MPH; Arkansas—MaryMcGehee, PhD;
Colorado—Alyson Shupe, PhD; Connecticut—Jennifer Morin,
MPH; Delaware—George Yocher, MS; Florida—Avalon
Adams-Thames, MPH, CHES; Georgia—Chinelo Ogbuanu,
MD, MPH, PhD; Hawaii—Emily Roberson, MPH, PhD;
Illinois—Theresa Sandidge, MA; Iowa—Sarah Mauch, MPH;
Louisiana—Amy Zapata, MPH; Maine—Tom Patenaude,
MPH; Maryland—Diana Cheng, MD; Massachusetts—Emily
Lu, MPH; Michigan—Cristin Larder, MS; Minnesota—Judy
Punyko, PhD, MPH; Mississippi—Brenda Hughes, MPPA;
Missouri—Venkata Garikapaty, MSc, MS, PhD, MPH;
Montana—JoAnn Dotson; Nebraska—Brenda Coufal; New
Hampshire—David J. Laflamme, PhD, MPH; New Jersey—
WALLENBORN AND MASHO
Lakota Kruse, MD; New Mexico—Eirian Coronado, MPH;
New York—Anne Radigan-Garcia; New York City—Candace
Mulready-Ward, MPH; North Carolina—Kathleen JonesVessey, MS; North Dakota—Sandra Anseth; Ohio—
Connie Geidenberger, PhD; Oklahoma—Alicia Lincoln,
MSW, MSPH; Oregon—Kenneth Rosenberg, MD, MPH;
Pennsylvania—Tony Norwood; Rhode Island—Sam VinerBrown, PhD; South Carolina—Mike Smith, MSPH; Texas—
Rochelle Kingsley, MPH; Tennessee—David Law, PhD;
Utah—Lynsey Gammon, MPH; Vermont—Peggy Brozicevic;
Virginia—Marilyn Wenner; Washington—Linda Lohdefinck;
West Virginia—Melissa Baker, MA; Wisconsin—Katherine
Kvale, PhD; and Wyoming—Amy Spieker, MPH, and the CDC
PRAMS Team, Applied Sciences Branch, Division of Reproductive Health.
Disclosure Statement
No competing financial interests exist.
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Address correspondence to:
Jordyn T. Wallenborn, MPH
Division of Epidemiology
Department of Family Medicine and Population Health
School of Medicine
Virginia Commonwealth University
830 East Main Street, Suite 821
P.O. Box 980212
Richmond, VA 23298-0212
E-mail: [email protected]