Condition category
Nutritional, Metabolic, Endocrine
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Gestational diabetes mellitus (GDM) is a condition that can occur in pregnancy and is a growing health problem. It can lead to long term complications such as type 2 diabetes and cardiovascular diseases for both the mother and the baby. A ‘Mediterranean-style’ diet (Med Diet) has been associated with greater quality of life and with prevention of cardiovascular diseases. The aim of this study is to assess the effects of a lifestyle intervention based on this ‘Med Diet’ and physical activity/exercise (beginning after the first gestational visit and during the whole pregnancy) on the incidence of GDM rate. In addition, we will carry out a number of genetic tests.

Who can participate?
Pregnant women above 18 year old, with normal fasting glucose values in the first gestational assessment.

What does the study involve?
Participating women will be randomly allocated to one of two groups: a ‘Med Diet’ group (free olive oil and nuts plus personalized dietary advice) or a ‘Control’ group (standard treatment with recommendations to cut down on all types of fat and training program).

What are the possible benefits and risks of participating?
Not provided at time of registration

Where is the study run from?
Hospital Clínico San Carlos, Madrid (Spain)

When is study starting and how long is it expected to run for?
From January 2014 to December 2015

Who is funding the study?
Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Spain.

Who is the main contact?
Professor Alfonso Luis Calle-Pascual

Trial website

Contact information



Primary contact

Prof Alfonso Luis Calle-Pascual


Contact details

Endocrinology and Nutrition Department
St Carlos Hospital. 1ªSur
Profesor Martin lagos s/n
34 91 3303281

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Reduction in the incidence of gestational diabetes mellitus (GDM) with MedDiet/Lifestyle and its impact on genetic and epigenetic pattern expression in pregnant women and their offspring



Study hypothesis

In this project we have hypothesized that a lifestyle intervention based on the Mediterranean Diet (MedDiet) and physical activity/exercise, beginning after 1st gestational visit [8-12 gestational weeks (GWs)] and throughout the pregnancy, will reduce the incidence of gestational diabetes mellitus (GDM) in women with normal fasting plasma glucose (FPG).

Ethics approval

St Carlos Hospital Ethics Committee; 22nd July 2013

Study design

Single centre clinic-based prospective randomized interventional study with two parallel groups

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

GP practices

Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Gestational Diabetes Mellitus


Eligible women will be randomly assigned to one of two groups:
1. Control group: Women are assigned to standard treatment with recommendations to reduce all types of fat from both animal and vegetable sources including nuts and olive oil, and a training program. This prudent diet recommendation represents a contribution of total fat less than 30% of the total energy intake, and carbohydrate intake of more than 50%. Women will be followed up by the Obstetric Department
2. MedDiet group: Women receive free virgin olive oil (1 litre/week) and mixed nuts (150 g/week) and the training program. Dietitians will give personalized dietary advice to participants with instructions regarding use of olive oil for cooking and dressing, increased consumption of fruit, vegetables, legumes, fish and avoidance of red or processed meat, butter, cream, fast food, sweets, pastries, and sugar-sweetened beverages. This intervention diet is comprised of an intake of approximately 35-40% of the total fat (predominantly unsaturated fatty acids) and 40-45% of the low glycemic index carbohydrates, maintaining a protein intake of 20%, similar to the control diet. Nutrition interventions are aimed to achieve a lifestyle score >10 based on Diabetes Nutrition and Complications Trial (DNCT) previously reported. Women will be followed up by the Endocrinology Department.

Intervention type



Not Applicable

Drug names

Primary outcome measures

To define the prevention of GDM (evaluated at 24-28 GWs with HAPO criteria) after the lifestyle intervention based on MedDiet and physical activity/exercise, as compared to standard treatment, in women with normal FPG at the 1st gestational visit (8-12 GWs)

Secondary outcome measures

1. To define the parameters of gestation length, fetal development, delivery characteristics such as cesarean delivery and instrumental vaginal birth, placental weight, and newborn data such as newborn weight, Apgar test values, and cord blood pH. Timepoint: at delivery, Visit 4.
2. To define functional genetic risk of developing GDM focusing on obese and non-obese pregnant women. Method and timepoint: HumanOmniExpress Infinium Illumina Exome v1.0, which allows the genotyping of approximately 950,000 markers in total sample. Of these, 700,000 are included in the common variants HumanOmniExpress Infinium (MAF> 5%) and 250,000 variants are included in the Human Exon Exome BeadChip. Eight samples can be hybridized per chip. Measured at Visit 0.
3. To investigate the effects of MedDiet and scheduled physical exercise/activity on inflammatory biomarkers in pregnant women. Method and timepoint: adiponectin, leptin, insulin and proinsulin will be determined by radioimmunoassay (Linco SA). hsCRP, sCD40L and Lp-PLA2 will be determined by specific ELISA kits. Visit 0-6.
4. To investigate the effects of MedDiet and scheduled physical exercise/activity on epigenetic mechanisms (DNA methylation and miRNA expression) in pregnant women and their offspring. If confirmed, it would represent a novel epigenetic mechanism for regulation of gene expression in the offspring (method and timepoint: we will perform a genome-wide DNA methylation analysis with the Illumina HumanMethylation450 BeadChip, following the Illumina Infinium HD Methylation protocol, using DNA obtained from whole blood. Quantitative methylation-specific PCR assay [qMSP]: validation of the most significant loci. Quantitative MSP will be performed with a 7500 Real-Time PCR System (Applied Biosystems). The primers will be designed using the MethPrimer website. Visit 0-2-4-6.
5. To investigate whether the MedDiet and scheduled physical exercise/activity alters the composition of the gut microbial flora both in the women and their offspring (method and timepoint: fecal collection and bacterial DNA quantification: DNA of microbial flora contained in the stool samples will be isolated using the PSP Spin Stool DNA PLUS Kit (Invitek Biotechnology and Biodesign). Visit 0-2-4-6.
6. To evaluate the impact of all of these parameters on the health of newborns in the first year of life
7. To estimate changes in HbA1c, insulin, HOMA, lipid profile, body weight, blood pressure, adherence to changes in lifestyle estimated by Med Score and urinary hydroxytyrosol levels and plasma alpha-linolenic acid levels (to confirm compliance in the group receiving MedDiet (extra-virgin olive oil and mixed nuts). Timepoint: Visit 0-2-4-6
8. To estimate the conversion rate to abnormal glucose tolerance (type 2 diabetes mellitus, IFG and IGT) of women with prior gestational diabetes mellitus (GDM) between 6 and 12 weeks after delivery. Method: oral glucose tolerance test (OGTT) measured at Visit 5.

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Women aged over 18
2. With normal fasting glucose values (< 92 mg/dl) in the 1st gestational assessment (8-12 GWs)
3. Who sign the informed consent

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Women with fasting glucose levels >92 mg/dl in the 1st gestational assessment (8-12 GWs)
2. Multiple pregnancy
3. Nut allergy or any other medical condition
4. Ongoing medication
5. Significant disability that would prevent the participant from complying with trial consent, treatment and follow-up procedures or potentially jeopardize her medical care

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Endocrinology and Nutrition Department

Sponsor information


The Health Research Institute at the Hospital Clinico San Carlos (Spain)

Sponsor details

Instituto de Investigación Sanitaria del Hospital Clínico San Carlos
Profesor Martin Lagos s / n
28040 Madrid
+34 913303793

Sponsor type

Research organisation



Funder type

Research organisation

Funder name

Institute for Health Research San Carlos (Instituto de Investigacion Sanitaria San Carlos)(IdISSC) (Spain)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Funder name

Foundation for Biomedical Research - Hospital Clinico San Carlos (Fundacion Para La Investigacion Biomedica - Hospital Clinico San Carlos) (Spain)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes