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ORP: Nutrition Prescription for Gestational Weight Gain (2014)

Citation:

Asbee SM, Jenkins TR, Butler JR, White J, Elliot M, Rutledge A. Preventing excessive weight gain during pregnancy through dietary and lifestyle counseling: A randomized control trial. Obstetrics & Gynecology. 2009; 113 (2p 1): 305-312. 

PubMed ID: 19155899
 
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To examine whether intervention of intensive counseling regarding diet and lifestyle during pregnancy with routine prenatal care would reduce the number of women who exceed the IOM recommendations for pregnancy weight gain.

Inclusion Criteria:
  • Prenatal care established at six to 16 weeks of gestation
  • Age 18 to 49 years
  • All prenatal care received at the Resident Obstetrics Clinic in Charlotte, North Carolina between October 2005 and April 2007
  • English-speaking, Spanish-speaking or both
  • Singleton pregnancy.
  • Written informed consent.
Exclusion Criteria:
  • Prenatal care established at more than 16 weeks of gestation
  • Non-English speaking or non-Spanish speaking
  • Multiple pregnancy
  • BMI higher than 40
  • Pre-existing diabetes, untreated thyroid disease or hypertension requiring medication or other medical conditions that might affect body weight
  • Delivery at institution other than Carolinas Medical Center-Main
  • Pregnancy ending in premature delivery (less than 37 weeks)
  • Limited prenatal care (fewer than four weeks).
Description of Study Protocol:

Recruitment

Women who presented to the Resident Obstetric Clinic in Charlotte, North Carolina for prenatal care between October 2005 and April 2007.

Design

  • Study participants were stratified based on BMI (calculated based on participants' self-reported pre-pregnancy weight and height measured in clinic) into three categories
    • Group one included underweight and normal weight patients with BMI less than 26
    • Group two included overweight patients (BMI between 26 and 30)
    • Group three included obese patients (BMI greater than 30).
  • After stratification, participants were randomly assigned to either the control group, who received routine prenatal care for remainder of pregnancy, or the intervention group, who received  the standardized protocol of dietary and lifestyle counseling
  • Weights were taken at each routine obstetrical appointment and shortly before delivery on arrival at Carolinas Medical Center.
  • Total weight gain and BMI change from pre-pregnancy to just before delivery were examined and compared between study and control groups to determine efficacy of intervention.

Intervention

Intensive counseling program on diet and lifestyle during pregnancy:
  • Initial visit: Visit with Registered Dietitian to receive a standardized counseling session, including information on pregnancy-specific dietary and lifestyle choices with:
    • Recommendations for a patient-focused caloric value divided in a 40% carbohydrate, 30% protein and 30% fat method
    • Instructions to engage in moderate-intensity exercise at least three times weekly and preferably five times per week
    • Received information on appropriate weight gain during pregnancy using IOM guidelines.
  • Follow-up visits: Health care provider (physician or nurse practitioner) informed participant whether weight gain was at appropriate level and provided praise and encouraged if weight gain was within IOM guidelines; if not. diet and exercise regimen were reviewed and recommendations for improvement if weight gain was not within IOM guidelines.

Statistical Analysis

  • Using an 80% power and an alpha of 0.05, 61 participants in each treatment arm were required to achieve overall statistical significance
  • Potential differences between two groups analyzed using X2 tests and T-tests (or Fisher exact tests and Mabb-Whitney tests for sparse and non-normally distributed data, respectively)
  • Multi-variable logistic regression models
  • P value 0.05 used to define statistical significance.
Data Collection Summary:

Timing of Measurements

  • Complete history and physical examination at start of study: Included height and pre-pregnancy weight
  • Weight measured at each visit and shortly before delivery on arrival at Carolinas Medical Center using balance beam scale and charted on IOM Gestational Weight Gain Grid
  • Demographic information collected at study initiation
  • Labor and delivery details at time of delivery

Dependent Variables

  • Total weight gain during pregnancy
  • BMI change from pre-pregnancy to just before delivery
  • Rate of adherence to IOM guidelines between groups
  • Mode of delivery
  • Rate of operative vaginal delivery
  • Neonatal weight
  • Incidence of preeclampsia, gestational diabetes, vaginal and perineal lacerations and shoulder dystocia.

Independent Variables

Provision of intensive counseling regarding diet and lifestyle during pregnancy.

Control Variables

  • Race
  • Tobacco use
  • Level of education
  • Gravidity
  • Parity
  • Age
  • Enrollment gestational age.
Description of Actual Data Sample:
  • Initial N: 108 subjects (108 females)
  • Attrition (final N): 100 subjects (100 females).

Age

  • Intensive counseling group: 26.7±6.0 years
  • Routine care group: 26.4±5.0 years
  • No statistically significant difference between groups.

Ethnicity

  • Intensive counseling group: 26.3% African American, 5.3% Asian, 8.8% white, 57.9% Hispanic, 1.8% other
  • Routine care group: 21.4% African American, 2.4% Asian, 19% white, 54.8% Hispanic, 2.4% other
  • No statistically significant difference between groups.

Other Relevant Demographics

Level of education:
  • Intensive counseling group: High school graduate or less, 68.4%; high school graduate or more, 31.6%
  • Routine care group: High school graduate or less, 65.1%; high school graduate or more, 34.8%
  • X2 P=0.04.

Anthropometrics

Study arms not statistically different with respect to pre-pregnancy weight, height and BMI.

Location

Charlotte, North Carolina.

 

Summary of Results:

Key Findings

  • Rate of adherence to IOM guidelines between groups:
    • No difference in rate of adherence to IOM guidelines between groups: 61.4% of participants were adherent to IOM guidelines in intervention group and 48.8% were adherent in routine care group (P=0.21)
    • Women in overweight and obese BMI groups are less likely to adhere to IOM guidelines:
      • Women with healthy BMI were adherent 80% (intensive counseling) and 68.8% (routine care) of the time
      • Overweight women in each group were adherent 30% (intensive counseling) and 25% (routine care) of the time
      • Obese women in each of the groups were adherent 33.3% (intensive counseling) and 20% (routine care) of the time.
    • No statistically significant difference in adherence across BMI groups between intensive counseling and routine care groups when adjusted for BMI
    • Most predictive factor of IOM adherence was normal pre-pregnancy BMI
    • Parous women were nearly six times as likely to adhere to IOM guidelines, as were nulliparous women (odds ratio 6.2; CI: 1.6 to 24.1, P<0.01).
  • Total weight gain during pregnancy:
    • Intensive counseling group participants gained significantly less weight (28.7±12.5 pounds compared with 35.6±15.5 pounds, P=0.01) than routine care group participants
    • Nulliparous participants gained significantly more weight than parous participants (36.5±14.5 pounds compared with 27.7±12.7 pounds) (P<0.01)
    • Women who were heavier pre-pregnancy were more susceptible to excessive weight gain in pregnancy.
  • BMI change from pre-pregnancy to just before delivery
  • Mode of delivery:
    • Cesarean delivery rate in routine care group (27.9%) was greater than that in the intensive counseling group (14%, P=0.09)
    • Average weight gained by those who delivered vaginally (30.4±13.4 pounds) was less than the average weight gained by those who delivered via cesarean (36.8+16.3 pounds, P=0.07).
  • Neonatal weight: Patients who were not adherent to IOM guidelines had significantly heavier neonates (adherent 3,203.2g±427.2g compared with non-adherent 3,517.4g±572.4g, P<0.01)
  • Incidence of pre-eclampsia, gestational diabetes mellitus, vaginal and perineal lacerations and shoulder dystocia: No statistically significant differences were noted between the groups. 
Variables Not IOM Adherent (N=44) IOM Adherent (N=56) Statistical Significance of Group Difference
Pre-pregnancy weight (lb) 154.3±33.4 134.2±32.2 <0.01
Body mass index (kg/m2) 27.8±5.7 23.7±4.8 <0.01
Enrollment weight (lb) 164.4±33.8 136.4±31.4 <0.01
Final weight (lb) 194.4±29.3 159.3±26.4 <0.01
Weight change (lb) 40.1±14.5 25.1±9.9 <0.01

 
Author Conclusion:

Program of intensive counseling regarding appropriate dietary and lifestyle habits during pregnancy did reduce weight gain in comparison with a control population receiving routine prenatal care. However, the intervention did not result in a significant increase in adherence to IOM guidelines. Weight loss achieved by the intervention could result in a decrease in antepartum, intra-partum and post-partum complications as well as resulting in a reduction in post-partum weight retention and obesity in the non-pregnant state, which should reduce overall burden of obesity-related disease such as diabetes mellitus and cardiovascular disease.

Funding Source:
Not-for-profit
Carolinas Healthcare Foundation
Other non-profit:
Reviewer Comments:
Study unable to achieve pre-determined power.
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? 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
  3.3. 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.) Yes
  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? 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? 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
  6.8. 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)? 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
  9.1. 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