PONCH is an ongoing prospective, longitudinal study investigating the influence of diet, obesity and gestational diabetes (GDM) on maternal and child metabolic health. Some of the specific aims of PONCH are to better understand how body composition, insulin resistance and energy metabolism change during and after pregnancy in women of normal body weight, with obesity or with GDM, and how this affects the body composition and growth of their children. Another important aim is to evaluate insulin resistance after GDM in order to better be able to predict the development of type-2-diabetes in these women. Here, we also establish the influence of life style factors in the transition from GDM to type-2-diabetes. Our hope is that our research will influence future clinical care of women with GDM.

Gestational diabetes

Obesity and overweight in pregnant women are increasing in all countries in the Western world (today 30-50 percent). In Sweden, about 40 percent of women are currently reported to be overweight or obese when pregnancy begins and the incidence has risen sharply over the past 10-15 years. These women are at increased risk of developing gestational diabetes (GDM). Women with GDM also have an increased risk of pregnancy and childbirth complications and a significantly increased risk of developing type 2 diabetes mellitus (T2D) after childbirth (about 20-30 percent within five years of pregnancy). Heredity is an important factor for the development of T2D and GDM, and both diseases are characterized by decreased insulin sensitivity and defects in the release and production of insulin. There is a close genetic link for both of these diseases that often occur in the same families, but at the same time there are individual differences in the risk of getting sick. Half of the pregnant women who develop GDM lack known risk factors, but these cases could be explained by external influences, such as obesity and weight gain, and the quality or distribution of fat in the body.

Monitoring pregnancy in different groups of women

As a part of our PONCH (Pregnancy Obesity Nutrition Child Health) study, we study pregnant women who are either obese, diagnosed with GDM during pregnancy or are normal weight with normal glucose tolerance. On three occasions during pregnancy (first, second and third trimester), blood samples are taken for analysis of hormones, fatty acids and inflammatory parameters as well as a fat biopsy in the abdominal subcutaneous fat (first and third trimester). From this, the importance of hormones/peptides from adipose tissue for weight changes as well as the risk of impaired glucose tolerance during and after pregnancy can be studied. These women are also followed for insulin sensitivity, body weight and body composition after childbirth. The women are then examined after 3 and 5 years to identify risk factors / biomarkers including metabolic profile (metabolomics / mass spectrometry analyzes) for T2D disease.

The importance of post-pregnancy follow-ups

In addition to the prospective study, we also invited all women in the Gothenburg area who, five years earlier in 2005-09, had a GDM (n = 542) to investigate glucose tolerance with oral glucose tolerance test (OGTT), blood sampling (as in the prospective study) and a fat biopsy. Of the participating women (n = 238), we found that 19 percent had developed T2D (n = 44) and 3 percent type 1 diabetes (n = 8), while 19 percent had impaired glucose tolerance (IGT) and 59 percent normal glucose tolerance (NGT) ( n = 139) five years after her pregnancy. Further follow-up is ongoing for these women at 10 years after childbirth, where the same sampling and measurements are performed, as well as a supplementary bike- and strength test and a DXA measurement.

In 2019 we started a new project in which we invite all women in the Gothenburg area who have had some known risk factor and therefore were tested for GDM in 2017-18. The women are invited, regardless of whether they were diagnosed during their pregnancy or not, at 18 months after delivery and offered blood samples, OGTT and anthropometric measurements. For those who wish, a supplementary bike- and strength test and DXA measurement are offered.

Snapshot at cesarean sections

We also have ongoing projects where we are interested in investigating the role of the brain and how hormones and neuropeptides affect appetite control and energy balance during pregnancy. In this project we collect spinal fluid and placenta among other things at elective caesarean sections