Projectdetails

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Pregnancy Outcomes and Maternal Insulin Sensitivity (PROMIS)

Keywords:
pregnancy insuline-glucose metabolism Neonatal growth

Researchers:
S.A. Scherjon
E. van der Beek
A. Kdekian
|H. Lutgers
M. Sietzema

Nature of the research:
Study design: The PROMIS study is a prospective exploratory cohort study where maternal insulin sensitivity during pregnancy will be monitored in association to (adverse) offspring outcomes. In the beginning of the second trimester (week 12-16) a MTT enriched with labeled glucose will be given to the study participants as will be done mid pregnancy (week 24-28) to compare to the standard OGTT (week 24-28). In addition, the MTT will be given to the study participants 3 months postpartum to study insulin sensitivity. Maternal anthropometrics and adiposity during pregnancy as well as fetal sonography and neonatal adiposity and anthropometrics will be monitored throughout the study period. Additionally questionnaires concerning lifestyle and eating behavior will be taken. Study population: The study population will consist of healthy singleton pregnant women at mildly elevated risk (BMI ≥25 kg/m2) for complications with fasting plasma glucose (FPG) levels ≤7,0, mmol/l and random blood glucose levels ≤11,0 mmol/l. The blood glucose test will exclude pregnant women with undiagnosed diabetes mellitus (DM) 1 and 2. Pregnant women with a known history of DM 1 and 2 are not eligible to participate in the PROMIS study.

Fields of study:
gynaecology pediatrics obstetrics

Background / introduction
The worldwide prevalence of overweight and obesity is rapidly increasing, also affecting women of reproductive age. The prevalence of overweight women between 30-40 years in the Netherlands in 2017 was 39%. Women with a BMI ≥25 kg/m2 have excess adipose tissue which reduces insulin sensitivity and explains the correlated adverse outcomes for both mother and child.

Insulin sensitivity changes over the course of pregnancy due to the effect of placental hormones and is therefore normally decreased by the end of the second trimester to ensure a continuous supply of nutrients towards the growing fetus. Insulin resistance leads to beta-cell proliferation and larger volume of individual beta-cells, returning to non-pregnant levels after parturition. When beta-cell proliferation is not or inadequately increased, this may lead to hyperglycemia. It is shown that small increases in maternal glucose levels have a linear relationship with adverse outcomes. Maternal adverse outcomes are pre-eclampsia, caesarian section and gestational diabetes mellitus (GDM) on the short term and increased risk of weight retention and non-communicable diseases like cardiovascular diseases and diabetes mellitus type 2 (DM2) on the longer term. Adverse outcomes in infants are macrosomia, large for gestational age (LGA), small for gestational age (SGA) on the short term and a higher risk on childhood obesity and non-communicable diseases on the longer term. Adequate maternal insulin sensitivity throughout pregnancy is therefore critical.

Small maternal glucose increases could already be detected in an early stage of pregnancy. In the Netherlands hyperglycemia is standardly examined at the end of the second trimester in an at risk population by an oral glucose tolerance test (OGTT). This test is less suitable to detect mild hyperglycemia in early stages of pregnancy, with merely blood glucose levels as a result, and shows a lot of within subject variability. However markers of insulin sensitivity and related metabolic adaptations, for instance in lipid metabolism, may be a more straightforward measure that could potentially be detected earlier and allow for early intervention. An integration of postprandial responses of glucose/insulin following a meal challenge combined with lipid markers could provide clearer insights in maternal metabolic function. A test that could be used to examine this in more detail is a liquid meal tolerance test (MTT) which contains a balanced macro- and micronutrient composition. Assessing glucose homeostasis is not possible by only measuring glucose concentrations as there are numerous perturbations where glucose production and its utilization increases or decreases to the same extent without any changes in concentrations. For the understanding of the physiology and pathophysiology of glucose uptake and metabolism during pregnancy, glucose tracers should be followed.

The PROMIS study will specifically focus on the associations between insulin sensitivity in the mother in early pregnancy and fetal and neonatal outcomes with emphasis on growth and body composition. The investigators therefore hypothesize that when overweight pregnant women are challenged in early pregnancy with a MTT, the group of women with disturbed insulin sensitivity could be identified much earlier, and can therefore have a predictive role in adverse outcomes.
Research question / problem definition
Hypothesis:
We hypothesize that (early) pregnancy assessment of maternal glucose-insulin metabolism with an MTT in a moderate to high risk group identify more mothers at risk for adverse pregnancy outcomes compared with standard OGTT testing at 24-28 weeks.
Workplan
The students will be a big part of the clinical study. There will be 7 moments after the MTT or OGTT where blood from the pregnant women needs to be drawn. Therefore we will apply a tap which we can take blood from during the two hours postprandial. It is a must that the students know how to do this. The student will help set up the material for drawing the blood and help the PhD student with other small during the two hours of tasks like performing a questionnaire and send the blood to the lab. Furthermore the student will help analysing sonographies, help with anthropometrics, manage data collection and analyse data.

Main study parameters/endpoints:
-Fasting levels of glucose and insulin
-PP responses of glucose and insulin collected at t=0,10,30,45,60,90 and 120 min after the MTT or OGTT.
References
HAPO Study
WHO
NVOG Dutch guidelines
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