EAL

BF: Artificial Nipple and Duration of Breastfeeding (2008)

Citation:

Cronenwett L, Stukel T, Kearney M, Barrett J, Covington C, Del Montel K, Reinhardt R, Rippe L. Single daily bottle use in the early weeks post-partum and breastfeeding outcomes. Pediatrics 1992; 90: 760-766.

PubMed ID: 1408551

Study Design:

Randomized controlled trial

Class:

A - Click here for explanation of classification scheme.

Quality Rating:

NEUTRAL: See Quality Criteria Checklist below.

Research Purpose:

To determine the effects of limited bottle use and infant temperament on breastfeeding outcomes.

Inclusion Criteria:

White, married coupled expecting first child and attending childbirth classes
Women committed to breastfeeding for at least six weeks.

Exclusion Criteria:

Not reported.

Description of Study Protocol:

Recruitment

Via mail, advertisement, personal solicitation at childbirth education classes

Design

Randomized controlled trial: Women randomized to one of two study groups; planned bottle vs. total breastfeeding

Intervention

Planned bottle group: Give one bottle of breast milk or formula per day for at least five days per week between weeks two to six post-partum
Total breastfeeding group: Avoid using bottles during two to six weeks post-partum (maximum two bottles per week allowed).

Statistical Analysis

Log rank test and Cox's proportional hazards model to assess associations between weaning rate and other co-variates. Multiple Logistic Regression used to study whether women had achieved 90% of breastfeeding goal, severe breastfeeding problems during study; P<0.05 significance level.

Data Collection Summary:

Timing of Measurements

Perinatal home interview, one week post-partum
Group assignment via coin toss; manual and electric pumps available for moms in bottle group; both groups studied between two and and weeks post-partum. Interviews during weeks two to six post-partum conducted over telephone.

Dependent Variables

Infant temperament (observational in-home and parental self-report)
Breastfeeding duration and weaning (weeks post-partum-monthly phone interviews)
Breastfeeding goal attainment (pre-natal questionnaire, months)
Number and severity of breastfeeding problems (23 events, three-point Likert scale, breastfeeding problems score done in perinatal home interview and monthly phone interviews).

Independent Variables

Group assignment (bottle vs. breastfeeding)

Co-variates included in analysis

Type of delivery
Receiving bottles in hospital
Mom's employment status at two months
Mom's pre-natal breastfeeding duration goal (months).

Control Variables

Timing of data collection and group assignment; homogeneous sample

Description of Actual Data Sample:

Initial N

128 couples

Attrition (final N)

121 couples: 58 breastfeeding, 63 bottle

Age

Moms 19-41 years; dads 20-52 years

Ethnicity

100% white

Other relevant demographics

Mom education 16±2.3 years; dad education 16.8±3.3 years

Location

New England and Midwest USA; Departments of Nursing and Community and Family Medicine, Dartmouth-Hitchcock Medical Center, Hanover, New Hampshire; Wayne State University College of Nursing, Detroit, Michigan, USA

Summary of Results:

Variables	Planned Bottle (N=63)	Total Breastfeeding (N=58)	Statistical Significance of Group Difference
Pre-natal breastfeeding duration goal, months	7.0±2.8	7.3±3.0	Not reported
"Difficult" infant temperament, percentage (parental self-report)	9.5	8.8	Not reported
Hospital bottle use, percentage	77.8	74.1	Not reported
C-section delivery, percentage	19.1	25.9	Not reported
Maternal employment at two months, percentage	28.3	30.4	Not reported
Occurrence breastfeeding problems, percentage	25	28	Not reported
Pre-natal breastfeeding duration goal achieved, percentage	71	76	NS, P=0.75

Planned bottle group weaned somewhat earlier than breastfeeding group, though there was no overall difference between the groups (P=0.28).
No effect due to interaction between group assignment and infant temperament
Prenatal duration goal was most important predictor of time to weaning (P=0.0001). Moms working outside home at two months post-partum weaned faster than those who did not (P=0.01). No interactions found for group assignment by infant temperament or occurrence of breastfeeding problems by pre-natal breastfeeding goal.
Group assignment had no effect on goal attainment.

Author Conclusion:

Women have a variety of options for approaches to breastfeeding, including the regular use of a single daily bottle-feeding.

Infant problems with breastfeeding or lack of maternal motivation to breastfeed may induce a relationship between early supplementation and early weaning for some mothers; this fact, however, is insufficient rationale for discouraging use of limited bottles among mothers who are otherwise motivated to breastfeed.

Funding Source:

Reviewer Comments:

Sample demographics not described; sample not representative of population; no blinding; no power calculation included (negative results); statistical significance between groups not reported.

Randomization was done by coin toss. The baseline characteristics of the two groups were not compared.

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)	Yes
	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)	Yes

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?	No
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
3.	Were study groups comparable?		No
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	No
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	???
	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?	N/A
	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?	Yes
	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?	No
	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.)	No
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	N/A
	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?	Yes
	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?	No
	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)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	Yes
	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?	No
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