BF: Artificial Nipple and Duration of Breastfeeding (2008)
Schwartz K, D'Arcy HJ, Gillespie B, Bobo J, Longeway M, Foxman B. Factors associated with weaning in the first 3 months postpartum. The Journal of Family Practice, 2002; 51: 439-444.
PubMed ID: 12019051To identify demographic, behavioral and clinical factors associated with breastfeeding termination in the first 12 weeks postpartum.
Pregnant women intending to breastfeed prenatally.
- None, except not meeting all inclusion criteria
- Excluded from the analysis were 111 women: 11 refused to participate and 100 could not be located.
Recruitment: Pregnant women were recruited from an orientation at a freestanding birthing center in suburban Detroit, MI, (75%), and from a single large company in Omaha, NE, when applying for maternity leave (25%) .
Design: In this prospective cohort study, the subjects were interviewed by telephone at three, six, nine and 12 weeks postpartum. During the computer-assisted interview, the subjects recalled each of the previous three weeks. The initial 15-minute to 20-minute interview collected demographic information; follow-up interviews were shorter in duration. The survey asked about breastfeeding practices and recent health events. Subjects were asked about possible difficulties, such as breast or nipple pain during nursing, nipple cracks, mastitis and other problems. Women who had stopped breastfeeding in the previous three weeks were asked to explain the reason for weaning. They were also asked if they had bottle-fed the infant, but were not asked about the bottle content or volume.
Statistical Analysis: Kaplan-Meier was used to describe the distribution of weaning. Log-rank test was used to assess group differences, whereas Cox-regression analysis assessed the relationships between demographic factors and time of weaning. Hazard ratios analyzed the association of the exposures between women who stopped breastfeeding at a particular time and those who continued. Two variables, number of daily feedings and duration of each feeding, were examined only in the first three weeks due missing information after this period. Weeks four to 12 were collapsed into a single interval.
Timing of Measurements
Breastfeeding practices and health/clinical factors were measured at three, six, nine and 12 weeks postpartum.
Dependent Variables
Weaning time.
Independent Variables
- Age
- Education level
- Breast fed previously
- Daily sleep hours
- Work return
- Depression
- Bottle feeding: Bottle contents or volume were not asked
- Pumping: Women who manually expressed or used a device to assist in expression
- Feeding time per day
- Nipple sores or cracks
- Mastitis
- Pain.
Control Variables
- Mother's age
- Education
- Previous breastfeeding experience.
Initial N: 1,057 were contacted, but only 946 participated in the first interview; 711 (75.2%) from Michigan, 235 (24.8%) from Nebraska
Attrition (final N): 658 (70%) completed all four interviews
Age: Michigan women were older than Nebraska women; 52% older than 30 years vs. 38.3% older than 30 years, respectively
Ethnicity: Not mentioned
Other relevant demographics: At least 63% of Michigan women had bachelor's degree and 38% had three or more children, while only 48.5% of Nebraska women had a bachelor's degree and 19.6% had three or more children. The groups were similar in race, household income and marital status. Information about pacifiers was not collected; therefore, exclusively breastfed infants may have also received pacifiers.
Anthropometrics: Not reported
Location: Detroit, MI, and Omaha, NE.
Relationships of Clinical and Behavioral Factors to Breastfeeding Cessation in the Same Week
Variables |
Weeks |
Michigan Women HR (95% CI) |
Nebraska Women HR (95% CI) |
Any pain |
1-3 4-12 |
14.7(6.8-32.0)** 0.3 (0.1-0.7)* |
9.1 (3.9-21.2)* 0.2 (0.1-0.5)* |
Mastitis | 1-3 |
5.7(1.3-25.9)* |
---- |
Days with pain |
1-3 4-12 |
1.1 (1.0-1.2)* 1.1(1.0-1.2) |
1.3 (1.0-1.5)* 1.1 (1.0-1.2)* |
Pumping |
1-3 4-12 |
2.2(1.1-4.6)* 0.2(0.1-0.5)** |
1.3(0.6-2.5) 0.3(0.1-0.5)** |
Bottle-feeding |
1-3 4-12 |
9.5(4.3-21.0)** 0.03(0.003-0.2)** |
1.8(0.9-3.5) 0.02(0.004-0.1)** |
Fewer than 10 minutes per day | 1-3 |
4.8(1.7,13.4)* |
2.2(0.6,8.1) |
Feedings per day | 1-3 |
0.7(0.6,0.8)** |
0.9(0.8,1.1) |
Fewer than seven feedings/day | 1-3 |
8.1(3.4-19.2)** |
1.8(0.7,4.6) |
--- few observations; HR= hazard ratio; *P<0.05 or less; **P=0.001 or less
PS: All data were adjusted for mother's age, education and previous breastfeeding experience
Other Findings:
- Demographic factors: 71.1% of women continued to breastfeeding until 12 weeks and 28% of them were exclusively breastfeeding. Michigan women were more likely to breastfeed at weeks two to 12 than Nebraska women; P<0.0001. A college degree was associated with 40% less weaning.
- Clinical and behavioral factors:
- Michigan women who expressed breast milk during the first three weeks were twice as likely to stop breastfeeding as those who did not pump.
- Breast-milk expression increased over time, from 30% of women pumping an average of three times per day in the first three weeks to 45% pumping five times per day in the last three weeks.
- Women who used bottles in the first three weeks were more likely to wean than those who did not use bottles.
- During weeks four through 12, both Nebraska and Michigan women who pumped were approximately 75% less likely to wean, whereas women who used a bottle for some feedings were 98% less likely to stop breastfeeding.
- Michigan women with more daily sleep were less likely to terminate breastfeeding during weeks four through 12 [HR=0.7(0.5-0.9), P<0.05], but an opposite trend was observed for Nebraska women 1.2(1.0-1.5).
- Percentage of women citing given reason for termination of breastfeeding
- Insufficient milk supply: 37.3% in the first interview, and 35% during weeks four through six
- Return to work: 53% in week nine, and 58% during week 12.
Younger women and less-educated women need additional support in their breastfeeding efforts. Exclusively breastfeeding for the first three weeks should be recommended. After the first three weeks, bottles and manual expression are not associated with weaning and may improve the likelihood of continuing breastfeeding, at least until 12 weeks.
Government: | NIH grant #30866 |
Intention and level of commitment were not measured in the study. Therefore, there may be bias because some of the variables associated with termination might be intentional activities of weaning rather than risk factors for termination.
Only 70% of women completed the four interviews were analyzed; however, the demographic data included all of the women who participated in the study.
The content and volume of bottle-feeding were not asked, and there is no information about pacifier use, which can be one factor for breastfeeding problems.
Quality Criteria Checklist: Primary Research
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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) | 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? | 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? | No | |
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? | No | |
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) | N/A | |
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.) | N/A | |
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? | No | |
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? | No | |
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%.) | 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? | ??? | |
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.) | ??? | |
5.3. | In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? | ??? | |
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? | N/A | |
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? | N/A | |
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? | No | |
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)? | No | |
8.6. | Was clinical significance as well as statistical significance reported? | Yes | |
8.7. | If negative findings, was a power calculation reported to address type 2 error? | N/A | |
9. | Are conclusions supported by results with biases and limitations taken into consideration? | No | |
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? | Yes | |
10.1. | Were sources of funding and investigators' affiliations described? | Yes | |
10.2. | Was the study free from apparent conflict of interest? | Yes | |