BF: Artificial Nipple and Duration of Breastfeeding (2008)

Citation:

Righard L, Alade MO. Breastfeeding and the Use of Pacifiers. Birth. 1997; 24: 116-120.

PubMed ID: 9271978
 
Study Design:
Cohort study
Class:
B - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To examine if incorrect sucking technique and pacifier use contribute to breastfeeding failure.

Inclusion Criteria:
  • Gave birth in the University Hospital in Malmo, a city in southern Sweden
  • Gave birth in November or December 1987
  • Had uncomplicated spontaneous delivery
  • Infant birth weight more than 2.5g and Apgar score of nine to 10.
Exclusion Criteria:

None except not meeting all inclusion criteria.

Description of Study Protocol:

Recruitment

Recruitment was vaguely described. I think all eligible mothers delivered in that hospital were invited and if so don't know how many mothers declined to enroll in the study. No description regarding informed consent and IRB approval.

Design

New mothers were observed in the hospital four to five days after birth to assess breastfeeding sucking technique (57 correct, 29 incorrect but corrected before discharge, 25 incorrect at discharge). Mothers were interviewed by phone by child health nurses at two weeks and at one, two, three and four months after delivery. Phone interview collected information about pacifier use and breastfeeding habits.

Blinding Used

Outcome assessors were blinded. The three child health nurses who conducted phone interviewers to obtain outcome data did not know the grouping of subjects. 

Statistical Analysis

Chi-square and Fisher's exact test.

 

Data Collection Summary:

Timing of Measurements

  • Breastfeeding technique was assessed at four to five days after birth
  • Pacifier variables and breastfeeding outcomes were assessed at two weeks and at one, two, three and four months after delivery.

Dependent Variables

Breastfeeding rate and problems.

Independent Variables

  • Breastfeeding sucking technique: Correct or not
  • Pacifier use: Yes or no; extensive (more than two hours per day) or not
  • Length of pacifier use: Number of hours per day.
Description of Actual Data Sample:
  • Initial N: 111 mother-infant pairs (111 pairs assessed for breastfeeding sucking technique)
  • Attrition (final N): 82 mother-infant pairs (those in analyses); drop-out was not mentioned even though final N was different from initial N
  • Age: Mean age of mothers was 27 years; range, 17 years to 40 years
  • Mean birth weight: 3.658kg in pacifier-users and 3.375kg in non-users (significantly different between the two groups with P=0.03)
  • Mean gestational age: No data
  • Ethnicity: Swedish
  • Other relevant demographics: All Swedish-speaking, all plan to breastfeed for at least six months and none returned to work before end of the study
  • Anthropometrics: Not reported
  • Location: Malmo in south Sweden.
Summary of Results:

Breastfeeding Rate at Four Months Among Pacifier Users and Non-Users

  Breastfeeding at Four Months Not Breastfeeding at Four Months

Total

Pacifier User

21

27

48

Pacifier Non-User

31

3

34

There were significantly lower breastfeeding rates among pacifier users than non-users (44% vs. 91%, P=0.03).

Breastfeeding Problems Among Extensive Pacifier Users and Limited or Non-Users

  Breastfeeding Problems No Breastfeeding Problems

Total

Extensive Pacifier User
(More than two hours per day)

20

4

24

Pacifier Non-User or Limited User
(Zero to two hours per day)

31

27

58

There were significantly more breastfeeding problems among pacifier users than non-users (83% vs. 53%, P=0.009).

Breastfeeding Rate at Four Months Among Pacifier Users and Non-users and Correct and Incorrect Sucking Pairs*

  Pacifier User Pacifier Non-User

P-Value Between Pacifier User and Non-User

Correct Sucking Technique

59% (20/34)

96% (22/23)

P=0.014

Incorrect Sucking Technique

7% (1/14)

82% (9/11)

P=0.015

P-Value Between Correct and Incorrect Sucking Technique P=0.02 P=not significant  

 *% are the percentage breastfeeding pairs; numbers in parentheses are the proportions of breastfeeding pairs over total number of pairs in that category

In both correct- and incorrect-sucking technique groups, there was significantly lower breastfeeding rate among pacifier users than non-users.

Breastfeeding rate differs by sucking technique among pacifier users, but not non-users.

Author Conclusion:

Pacifier use should be discouraged, and incorrect breastfeeding sucking technique should be corrected.

Funding Source:
Reviewer Comments:

Infant birth weight was significantly different between pacifier users and non-users. There was no analysis about whether this may become a confounder.

Recruitment method was vague. Also, there is no mention of rate of dropout nor reasons for dropout, even though the initial and final sample sizes did not add up.

Assessment on pacifier use and breastfeeding was done at five time points (two weeks and one, two, three and four months after birth), but only four-month results were extensively reported. Also, it was unclear pacifier use of which time point was used to categorize subjects during analysis.

No informed consent procedures or IRB approval was mentioned in this report.

It was unclear how the researchers decided which subjects with incorrect sucking technique should be corrected (among the 54 pairs with incorrect technique, 29 were corrected but 25 were not).

Many variables were not well-defined. For example, it is unclear if breastfeeding was defined as any breastfeeding or only exclusive breastfeeding. Extensive pacifier use was defined as more than two hours per day but it is unclear how or why that cut point was set. 

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? No
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? No
  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? 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) No
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  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.) Yes
  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? No
  4.1. Were follow-up methods described and the same for all groups? No
  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%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? No
  4.4. Were reasons for withdrawals similar across groups? ???
  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? Yes
  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.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? Yes
  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? No
  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? No
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? No
  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? No
  7.1. Were primary and secondary endpoints described and relevant to the question? No
  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? N/A
  7.5. Was the measurement of effect at an appropriate level of precision? ???
  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)? No
  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? No
10. Is bias due to study's funding or sponsorship unlikely? ???
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? Yes