BF: Artificial Nipple and Duration of Breastfeeding (2008)

Citation:

Santo LC, Oliveira LD, Giugliani ER. Factors associated with low incidence of exclusive breastfeeding for the first six months.  Birth. Sept 2007; 34 (3): 212-219.

PubMed ID: 17718871
 
Study Design:
Prospective Cohort Study
Class:
B - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To identify determinants of exclusive breastfeeding cessation before six months, including variables that generally receive little attention as potential risk factors for exclusive breastfeeding (influence of grandmothers, breastfeeding technique and sore nipples).

Inclusion Criteria:

Mothers living in city of Porto Alegre (southern Brazil) who had given birth to healthy singleton infants weighing at least 2,500g in the rooming-in ward; have started breastfeeding.

Exclusion Criteria:

Mother-infant pairs who had to be separated due to mother- or infant-related problems.

Description of Study Protocol:

Recruitment

Sample of mother-infant pairs was selected between June and November 2003; two pairs were selected by lots daily among those who met inclusion criteria.

Design

Prospective cohort study (six months).

Statistical Analysis

Exclusive breastfeeding (EBF) survival curve, the effect of covariates on exclusive breastfeeding duration was evaluated by Cox regression analysis; correlations P≤0.20 included in final model. Hazard ratios with 95% CI were used to measure effect of each association between potential risk factor and exclusive breastfeeding cessation before six months. Kaplan-Mayer method was used to calculate median exclusive breastfeeding duration. Significance level P≤0.05.

Data Collection Summary:

Timing of Measurements

Maternity ward (two days to three days postpartum)

  • Interview with mother
  • Breastfeeding technique assessed (positioning of infant; latching of infant to breast).

End of first month (30 days): Home visit

  • Questionnaire
  • Examination of breasts
  • Assessment of breastfeeding.

End of second, fourth, and sixth months: Telephone interview

  • Child's feeding
  • Pacifier use
  • Family support
  • Home visits performed if phone contact not made.

Mother-infant pairs followed up until exclusive breastfeeding stopped, or until end of sixth month.

Dependent Variables

  • Exclusive breastfeeding duration, number of days (child given only breast milk, no other liquids or solids)
  • Early cessation of exclusive breastfeeding (interruption before 180 days or 6 months of life)

Independent Variables

  • Maternal age
  • Skin color
  • Education
  • Cohabitation with partner
  • Child's grandmothers
  • Number of prenatal visits
  • Breastfeeding support during pregnancy
  • Type of delivery
  • Baby's sex
  • Parity
  • Duration of breastfeeding with previous children
  • Nipple trauma at maternity unit
  • Pacifier use at 30 days
  • Unfavorable positioning and latch-on at maternity unit and at 30 days.

Control Variables

  • Same researcher who conducted assessment in maternity ward conducted home visit/assessment at 30 days; timing of measurements.
  • For multivariate Cox regression, the variables that had a correlation with the outcome valued at P<0.20 by simple Cox regression were included in the final Cox regression model.
Description of Actual Data Sample:

 

Initial N: 220 mother-infant pairs

Attrition (final N): 213 up to first month; 208 up to two months, 203 up to four months, 197 up to six months

Age: 75.9% age 20 years or older

Ethnicity: 69.1% white

Other relevant demographics: 64.1% had eight or more years of school; 82.7% living with partner; 49.6% living with a grandmother; 47.3% primiparas; 78.6% had six or more prenatal visits; 34.9% had breastfeeding instruction during prenatal care; 13.4% received instruction during prenatal care about breastfeeding positioning; 71.8% vaginal delivery

Anthropometrics: Not reported for mothers; mean birth weight of babies 3,283.5±424.5g

Location: Maternity ward of Hospital de Clinicas de Porto Alegre, Porto Alegre, Rio Grande do Sul (southern Brazil).

 

Summary of Results:

 

42.3% moms presented nipple trauma when examined in the maternity unit two days to three days postpartum; while in the hospital, 11.9% of babies had received infant formula at least once; by 30 days, 63% of babies were using pacifiers. 

EBF Survival Curve:  At end of 30 days, 54% of babies still being exclusively breastfed; at 6 months, only 6.6% were EBF;  mean duration of EBF=30 days. 

Frequency of unfavorable positioning and latch parameters during breastfeeding two to three days postpartum and at 30 days: "baby's face not in front of breast and nose not opposite nipple" most frequently cited at both time points (97.7%, 87.3%, respectively), followed by baby's head and body not aligned (67.3%, 61.8%).  Symmetrical la\tch (98.6%, 89.7%) was most frequently cited at both time points.

Variables associated with EBF duration (bivariate analyses): Mothers age, number prenatal visits, living with partner, living with a grandmother, previous breastfeeding experience, use of pacifier at 30 days, number of both unfavorable positioning and latch-on parameters at two to three days postpartum (positioning only) and 30 days.

 Table. Multivariate Analyses for the Effect of Covariates on Exclusive Breastfeeding Duration

Variable Adjusted HR (95% CI)
Mom age younger than 20 years 1.48 (1.01-2.17)
Fewer than six prenatal visits 1.60 (1.10-2.33)
Duration of breastfeeding with previous children fewer than six months 1.27 (0.84-1.92)
No previous children 1.39 (0.95-2.04)
Living with partner 1.17 (0.78-1.76)
Living with maternal grandmother 1.10 (0.78-1.57)
Living with paternal grandmother 0.72 (0.48-1.08)
Use of pacifier during first month 1.53 (1.12-2.11)
Number of unfavorable latch-on parameters at end of first month 1.29 (1.06-1.58)
Number unfavorable breastfeeding positioning parameters at end of first month 1.01 (0.86-1.18)

Variables associated with early cessation of EBF: Mother younger than 20 years; fewer than six prenatal visits; use of pacifier in first month; unfavorable latch-on at first month. 

Risk of cessation of EBF before six months 1.72 (1.11-2.67) for pairs with just one of four risk factors; 2.83 (1.81-4.43) for two of four factors; 4.08 (2.24-7.42) for three or four of four factors compared to pairs with no risk factors. Linear trend as number of risk factors increased (P<0.001). 

Author Conclusion:

The findings of this study can help identify mother-infant pairs at increased risk of early cessation of EBF; the more risk factors present, the greater the risk. Intense and directed pro-breastfeeding interventions are needed.

Activities to promote EBF should be intensified for teen mothers and for those with less-than-ideal prenatal care, reinforcing the ill effects of pacifiers and including appropriate instruction in breastfeeding technique.   

Funding Source:
Government: Consehlho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)
Reviewer Comments:
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) N/A
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) N/A
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? Yes
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? No
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? No
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? Yes
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? N/A
  8.6. Was clinical significance as well as statistical significance reported? No
  8.7. If negative findings, was a power calculation reported to address type 2 error? Yes
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes