Obesity during pregnancy

Obesity during pregnancy is associate with a 3.5-times increase future risk of type 2 diabetes (T2D) in the child; concludes new research publish in Diabetologia. If the pregnant woman is overweight rather than obese; the increase risk of T2D in the child upto 40%. The study says strategies to reduce obesity and overweight in women of reproductive age are urgently require.

The short-term complications of maternal obesity are well recognize including gestational diabetes; pre-eclampsia; larger infants and higher likelihood of Caesarean delivery. In addition, there is now an increasing awareness that there are longer term health problems for infants born to obese mothers; for example, increase risk of premature cardiovascular disease and premature mortality.

This study, conduct by Professor Rebecca Reynolds, University of Edinburgh, UK and colleagues; examine the link between maternal body mass index (BMI) and the risk of the offspring developing a clinically confirm diagnosis of diabetes (however treated) right up to adulthood.

Pregnant women were overweight

The study link birth records of 118,201 children from 1950 to 2011 in the Aberdeen Maternity and Neonatal Databank (AMND); a unique databank of diverse obstetric information, with data from Scottish Care Information (SCI)-Diabetes; the national register for diagnose diabetes in Scotland. The analysis adjust for potential confounding factors, including maternal history of diabetes before pregnancy; maternal age at delivery, area-based socioeconomic status, parity, the stage of the pregnancy when the mother’s weight was measure; maternal history of high blood pressure, and the sex off the child.

The data show that 25% of the pregnant women were overweight and 10% were obese across all years studied. However, the proportion of obese mothers has increase; 5-fold from the years 1950-1959 (3%) to the years 2000-2011 (16%). Compare with normal weight mothers; being overweight or obese during pregnancy was associate with a significantly increase risk of any diabetes (type 1 or type 2) in the child; with an increase risk of 26% for overweight mothers and 83% for obese mothers.

However, when looking only at type 2 diabetes; the increase risks were even higher. Being an obese mother was associate with a 3.5 times increase risk of T2D in the child; while for overweight mothers; the associate increase risk was 40%. The underlying mechanism for the association between high maternal BMI and offspring type 2 diabetes is unknown. One theory is that obesity in the mother produces an adverse in-utero environment; with high levels of glucose, insulin and other metabolites leading to a ‘programming’ of adverse metabolic outcomes for the offspring.

Epigenetic changes in obese mothers

In addition, there are complex neuroendocrine, metabolic and immune/ inflammatory changes associate with obesity in pregnancy; that are likely to impact on hormonal exposure and nutrient supply to the fetus. Epigenetic changes  in the intrauterine environment in obese mothers; may also cause stress on the insulin producing beta cells in the pancreas of the unborn child; which can then lead to earlier onset of type 2 diabetes and raised cardiometabolic risk. Further research is needed to definitively explain these relationships.

They say: “This large cohort study, using over 60 years of pregnancy data link to the national diabetes dataset in Scotland; showed a significant association between maternal BMI and incidence of diabetes in the offspring. This association may partly explain the link between being overweight or obese during pregnancy and offspring cardiovascular disease and mortality rates—highlighting a potential target for intervention.”

There is an urgent need to establish effective approaches to prevention of obesity and diabetes among mothers and their offspring pregnancy represents a potential time to intervene with health advice for the family”. In the UK, data suggest around half of all women of childbearing age (covering age 16-44 years) are overweight or obese. Looking only at women aged 25-44 years, this proportion of overweight / obese women is almost 60%.