GDM: Medical Nutrition Therapy (2016)


Vinter CA, Jensen DM, Ovesen P, Beck-Nielsen H, Jørgensen JS. The LiP (Lifestyle in Pregnancy) study: a randomized controlled trial of lifestyle intervention in 360 obese pregnant women. Diabetes Care. 2011 Dec; 34 (12): 2,502-2,507. doi: 10.2337/dc11-1150. Epub 2011 Oct 4. PMID: 21972411

PubMed ID: 21972411
Study Design:
Randomized Controlled Trial
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
The aim of this randomized trial was to study the effects of lifestyle intervention on gestational weight gain and obstetric and neonatal outcomes in a large group of obese pregnant women.
Inclusion Criteria:
  • Women aged 18 years to 40 years
  • 10 to 14 weeks’ gestation
  • BMI of 30kg/m2 to 45kg/m2, as calculated from the pre-pregnancy weight or first measured weight in pregnancy.
Exclusion Criteria:
  • Prior serious obstetric complications
  • Chronic diseases (e.g., hypertension and diabetes)
  • Positive OGTT in early pregnancy
  • Alcohol or drug abuse
  • Non-Danish speaking
  • Multiple pregnancy.
Description of Study Protocol:


Women were recruited after referral to the Department of Gynecology and Obstetrics, Odense University Hospital.


  • In this non-blinded randomized controlled trial (RCT), after providing written consent eligible women were randomized to one of two arms: Intervention or control.
  • Throughout their pregnancy the Intervention Group received four separate diet counseling sessions and an exercise program (consisting of weekly aerobic classes, free fitness membership and exercise motivating initiatives)
  • Physical activity levels and eating habits were self-reported by both the Intervention and Control Groups at baseline and at 35 weeks gestation
  • A brief fitness test (the Danish step test) was performed at baseline and at the last visit before delivery to measure physical fitness
  • Both study groups were monitored throughout pregnancy using fasting blood samples, oral glucose tolerance tests (OGTT), sonar fetal biometry and measurements of maternal weight and blood pressure.


  • The Intervention Group received four separate diet counseling sessions and an exercise program (consisting of weekly aerobic classes, free fitness membership and exercise motivating initiatives)
  • Dietary counseling was performed by trained dietitians on four separate occasions (at 15, 20, 28 and 35 weeks gestation), with the aim of limiting gestational weight gain to five kg
  • The counseling included dietary advice based on the official Danish recommendations
  • Energy requirements for each participant were individually estimated according to weight and level of activity
  • Women in the Intervention Group were encouraged to participate in 30 to 60 minutes of moderate intensity physical activity and were equipped with a pedometer. Women in this group also had free full-time membership in a fitness center for six months, where they had closed training classes with physiotherapists for one hour each week. Training consisted of aerobic (low-step), training with light weights and elastic bands, and balance exercises. After physical training, the women were grouped four to six times in pregnancy with the physiotherapist using coaching-inspired methods for improving participants’ integration of physical activities in pregnancy and daily life.
  • The women in the Control Group received the same initial information about the purpose and content of the study, including access to a website with advice about dietary habits and physical activities in pregnancy, but no additional intervention.

Statistical Analysis

  • Between-group differences were analyzed using the chi-squared test; the student T-test and the Mann-Whitney U-test were also used for continuous variables.
  • Sub-analyses were done according to the IOM gestational weight gain recommendations using ANOVA or chi-squared test
  • The Wilcoxon rank-sum test was used for a power calculation (85 percent power). 
Data Collection Summary:

Timing of Measurements

  • Blood samples were collected at gestational age 12 to 15 weeks (used as baseline measurement), at 28 to 30 weeks and at 34 to 36 weeks
  • A fitness test was done at baseline and at the last visit before delivery. 

Dependent Variables

  • Gestational weight gain (kg; calculated as weight at 35 weeks of gestation minus weight measured at recruitment)
  • Two hour OGTT (mmol per L)
  • Fasting insulin (mU per L)
  • HOMA-IR (homeostasis model assessment of insulin resistance)
  • Fasting cholesterol (mmol per L)
  • Fasting HDL (mmol per L)
  • Fasting LDL (mmol per L)
  • Fasting triglycerides (mmol per L)
  • Systolic blood pressure (mmHg)
  • Diastolic blood pressure (mmHg)
  • VO2max (ml/kg-1x min-1).
Independent Variables

Improved diet and increased physical activity.

Description of Actual Data Sample:
  • Initial N: 360 women
  • Attrition (final N): 150 women in the Intervention Group; 154 women in the Control Group
  • Age: 29 years (27 to 32) for the Intervention Group; 29 years (26 to 31) for the Control Group
  • Ethnicity: Danish, Caucasian
Other relevant demographics
Subjects were evenly matched.
  • Smokers
  • Primiparous
  • At least 12 years of school
  • At least three years of further education
  • In gainful employment.
Maternal BMI was evenly matched between groups.
  • Intervention Group: 33.4kg/m2 (31.7kg to 36.5kg/m2)
  • Control Group: 33.3kg/m2 (31.7kg to 36.9kg/m2). 
Summary of Results:
  • The Intervention Group had significantly lower gestational weight gain compared with the Control Group (7.4±4.6kg vs. 8.6±4.4kg, P=0.01)
  • There were no significant differences in clinical outcomes for pre-eclampsia or pregnancy-induced hypertension, gestational diabetes, Cesarean section, large for gestational age and admission to the neonatal intensive care unit
  • There was no difference in the rate of women diagnosed with gestational diabetes between Intervention and Control Groups (6.0% vs. 5.2%, P=0.760)
  • Women in the Intervention Group had a significantly lower change in fasting insulin from randomization to 28 weeks gestation, compared with the Control Group (3.1±4.9mU per L vs. 4.3±4.9mU per L, P=0.015)
  • Increase in insulin resistance (HOMA) was lower in the Intervention Group, compared with control subjects at 28 to 30 weeks gestation (0.7±1.3 vs. 1.0±1.3, P=0.022) 
  • At 34 to 36 weeks' gestation insulin resistance was higher in the Control Group, although not statistically significant.

Other Findings

  • Compliance with exercise classes was low: 56% of women in the Intervention Group attended the aerobic classes for at least half of the sessions
  • 92% of subjects in the Intervention Group completed all four dietetic counseling sessions and 98% completed at least three sessions
  • 85% of the women in the Intervention Group responded affirmatively that participation in the study resulted in more healthy eating habits
  • Self-reported leisure time physical activity level was significantly improved in the Intervention Group
  • Spending at least two hours per week with leisure time physical activities making them break sweat or be short of breath increased from 29% to 56% during pregnancy. For the Control Group, physical activity level decreased from 34% to 25% and the difference in the third trimester was statistically significant (P<0.001)
  • 20% of women in the Control Group reported that they believed their participation in the study in itself had improved their lifestyle, despite no active intervention. 
Author Conclusion:
  • Lifestyle intervention during pregnancy could restrict gestational weight gain and limit the physiological increase in insulin resistance during pregnancy
  • The intervention did not significantly affect clinical obstetric outcomes, overall oral glucose tolerance test results or lipid profiles between groups. 
Funding Source:
The NoVo Foundation
University/Hospital: Department of Gynecology and Obstetrics, Odense University Hospital, Odense Denmark and the Department of Gynecology and Obstetrics, Aarhus University Hospital, Aarhus, Denmark
Reviewer Comments:
Same subjects and intervention as Vinter CA, 2014.
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.) 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? 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.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? Yes
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? Yes
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? ???
  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? Yes
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? 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? N/A
  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