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ORP: Nutrition Prescription for Gestational Weight Gain (2014)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

To evaluate the effects of a behavioral lifestyle intervention delivered during pregnancy to decrease the proportion of women who exceeded recommendations for gestational weight gains and increase the proportion who returned to pregravid weights by six months postpartum.

Inclusion Criteria:
  • Pregnant women, gestational age between 10 and 16 weeks 
  • BMI between 19.8 and 40
  • Non-smoking
  • Adults older than 18 years of age
  • Fluency in English
  • Access to a telephone
  • Singleton pregnancy
  • Written informed consent was provided.
Exclusion Criteria:
  • Gestational age less than 10 weeks or more than 16 weeks
  • BMI less than 19.8 or more than 40
  • Smoking
  • Age less than 18 years
  • Not fluent in English
  • No access to telephone
  • Multi-parity
  • Self-reported major health or psychiatric diseases
  • Weight loss during pregnancy
  • History of three or more miscarriages.
Description of Study Protocol:

Recruitment

  • Recruited by trained research assistants or nurses during the first prenatal visit of patients at one of six obstetric offices 
  • Referral slips were presented to research staff who phone-screened patients for eligibility.

Design

  • Randomized controlled trial
  • Baseline assessment was completed at the research center and then participants were randomly assigned into intervention or standard care
  • Randomization was computer-generated in randomly varying block sizes and stratified by clinic and BMI category.

Blinding Used

Clinic staff and physicians were blinded to subject randomization.

Intervention
  • Standard care included regularly scheduled visits with prenatal care providers and a brief face-to-face visit at study entry with he study interventionist and received study newsletters at two-month intervals that provided general information about pregnancy-related issues
  • Intervention group received standard care along with a behavioral lifestyle intervention designed to prevent excessive weight gains during pregnancy; no intervention was provided postpartum:
    • One face-to-face visit with an interventionist at the onset who discussed:
      • Appropriate weight gains during pregnancy
      • Physical activity (30 minutes of walking most day of the week)
      • Calorie goals (20kcal per kg)
      • Emphasis placed on decreasing high fat foods, increasing physical activity and daily self-monitoring of eating, exercise and weight.
    • Body-weight scales, food records and pedometers were provided
    • Automated postcards that prompted healthy eating and exercise habits were mailed weekly
    • After each clinic visit, women were sent personalized graphs of their weight gains with feedback
    • Three brief supportive phone calls from the dietitian during the intervention
    • Women who were over or under weight-gain guidelines during any one-month interval received additional phone class.
Statistical Analysis
  • Power analysis revealed that 200 women in each group were needed at baseline with the assumption of a 10% attrition rate and intent-to-treat analyses would provide 90% or more power to detect a 25% or more difference between the intervention and standard care in proportions that exceeded weight gain guidelines
  • For postpartum data, 30% attrition was assumed and an 81% power was provided to detect a 13.6% increase in the proportion of participants who achieved their pre-conception weights
  • Chi-square and T-tests were used to compare completes with non-completers and intervention compared with control groups
  • Multiple logistic regression analysis was used to examine the effects of treatment group and BMI category and their interaction on the proportion of women who exceeded the IOM recommended amount
  • All models were adjusted for clinic and other determinant confounders of estimates of excessive gestational gain
  • Multiple logistic regression analysis used to examine the effect of treatment group on the proportion of women who achieved their pre-conception weights at six months postpartum
  • Subsequent models examined the interaction between weight an treatment and the inclusion of six months postpartum breastfeeding status
  • Repeated-measures analysis of variance was used for secondary aims that assessed the effects of treatment group and BMI category on total weight gain and postpartum weight loss
  • R 2.11.1 and SPSS 18.0.1 were used for analyses.
Data Collection Summary:

Timing of Measurements

  • Recruitment occurred from 2006 to 2008
  • Assessments occurred at study entry, 30 week gestation and six months postpartum.

Dependent Variables

  • Proportion of women with excessive gestational weight gain:
    • Based on the 1990 IOM guidelines
    • More than 35 lb for normal weight women
    • More than 25 lb for overweight or obese women
    • Pre-pregnancy weight was self-reported.
  • Proportion of women at or below their pregravid weights at six months postpartum.

Independent Variables

Behavioral lifestyle modification focused on:
  • Appropriate pregnancy weight gain goals
  • Dietary intake
  • Physical activity
  • Self-monitoring.

 Control Variables

  • Maternal and fetal complications
  • Breastfeeding status.
Description of Actual Data Sample:

Initial N

  • Standard care: 200 women
  • Intervention: 201 women.

Attrition (final N)

  • Standard care: 182 women (9% attrition) 
  • Intervention: 176 women (12.5% attrition).

Age

  • Standard care: 28.8±5.2
  • Intervention: 28.6±5.2

Ethnicity

  • Standard care:
    • Non-Hispanic white: 67.5%
    • Latina and Hispanic: 19.6%
    • Non-Hispanic African American: 9.6%
    • Other: 3.3%.
  • Intervention:
    • Non-Hispanic white: 68.7%
    • Latina and Hispanic: 19.6%
    • Non-Hispanic African American: 7.1%
    • Other: 4.6%.

Other Relevant Demographics

  • Weeks gestation at entry:
    • Standard care: 13.5±1.8
    • Intervention: 13.6±1.8.

Anthropometrics 

BMI kg/m2:
  • Standard care: 26.48±5.9
  • Intervention: 26.32±5.6.

Location

Providence, Rhode Island.

 

Summary of Results:

Key Findings

  • Intervention decreased the percentage of normal weight women who exceeded weight gain guidelines
  • Percentage of participants with total weight gain greater than IOM guidelines
  • Normal pre-pregnancy weight:
    • Standard care: 52.1%
    • Intervention: 40.2%
    • Odds ratio for treatment effect was 0.38 (95% CI: 0.20, 0.87; P=0.003).
  • Overweight or obese pre-pregnancy weight:
    • Standard care: 61.1%
    • Intervention: 66.7%
    • No significant treatment effect was observed (P=0.33).
  • Percentage of participants at pre-conception weight or below
    • Normal pre-pregnancy weight:
      • Standard care: 20.7%
      • Intervention: 35.6%.
    • Overweight or obese pre-pregnancy weight
      • Standard care: 16.7%
      • Intervention: 25.6%.
    • On the basis of multiple logistic regression analysis, the odds ratio fro the main effect for treatment was 2.1  (95% CI: 1.3, 3.5; P=0.005)
    • No significant interaction with weight category (P=0.71).

Other Findings

  • Exceeding weight gain goals was significantly related to a higher gestational age at delivery (OR: 1.2; 95% CI: 1.1, 1.4; P=0.0005) but not to race, parity, age or clinic status
  • Effect of breastfeeding:
    • Significantly related to a higher odds of women achieving their six months pre-conception weights or below (OR: 2.4, 95% CI: 1.4, 4.2; P=0.002)
    • 40.5% of breastfeeders (53 of 131 subjects) achieved pre-conception weights postpartum
    • 22.3% of exclusive formula feeders (35 of 157 subjects) achieved pre-conception weights postpartum.
  • Pregnancy complications:
    • Maternal gestational hypertension:
      • Significant treatment by weight interaction was observed (OR; 0.15; 95% CI: 0.02, 0.75; P=0.02)
      • Intervention associated with lower odds in normal weight subjects but had no significant effect on overweight or obese subjects.
    • Macrosomia: Main effects for weight with normal weight women having lower odds (OR: 0.26; 95% CI: 0.06, 0.99; P=0.05)
    • Cesarean delivery: Main effects for weight with normal weight women having lower odds (OR: 0.38; 95% CI: 0.26, 0.74; P=0.004).
Author Conclusion:

This study indicates that a low-intensity, partially mail-based behavioral intervention that targets dietary intake, physical activity and weight monitoring can promote healthy pregnancy weight gain in normal weight women and prevent high postpartum weight retention in normal weight women and overweight women.

Funding Source:
Government: National Institute of Health
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) Yes
  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
  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
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
  1. Was the research question clearly stated? Yes
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.1. 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
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
  1.3. Were the target population and setting specified? Yes
  2. Was the selection of study subjects/patients free from bias? 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
  2.1. 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
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? 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
  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) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  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? 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? 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
  3.5. 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
  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. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? 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
  4.2. 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
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? 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
  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. 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? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? Yes
  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? N/A
  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
  5.4. 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? 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
  6.3. 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
  6.4. 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? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? Yes
  6.6. Were extra or unplanned treatments described? Yes
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  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
  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. 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
  7.1. 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
  7.2. 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
  7.3. 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
  7.4. 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
  7.5. 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
  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
  8.1. 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
  8.4. 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)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  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? Yes
  9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? 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
  10.2. Was the study free from apparent conflict of interest? Yes