Maternal obesity in gestational diabetes mellitus: investigating its potential use in identifying women at risk

The primary aims of this thesis were to 1) identify the modality of exercise which is most effective for improving glycaemic control in women at risk and diagnosed with gestational diabetes mellitus (GDM); 2) to determine the influence of maternal obesity and degree of glucose intolerance on neonatal hypoglycaemia and birth-weight over the 90th percentile; 3) to design a reliable non-invasive and non-time-consuming technique of measuring abdominal visceral and subcutaneous tissue in early pregnancy; 4) investigate the use of parameters of body composition as an early detector or risk stratification tool for GDM. A systematic literature review was undertaken to identify modality of exercise in the blood glucose control of women with or at risk of GDM. Initially, 428 journal articles were considered, with 12 included in the final synthesis. Interventions in women at risk of GDM were overall more successful in improving blood-glucose parameters, these lasted a duration of 10-24 weeks. As part of a retrospective study in a GDM cohort, data pertaining to pregnancy risk, biochemistry results from 75g-oral glucose tolerance test (OGTT), as well as other maternal and neonatal pregnancy outcomes were abstracted from patient medical records retrospectively (n=303). Maternal obesity, but not degree of glucose intolerance increased occurrence of neonatal hypoglycaemia. Multiparous women had greater risk of neonates born large for gestational age. In a prospective observational trial, anthropometric measures including 8-point skinfold measurements and abdominal subcutaneous and visceral fat measured via ultrasound were collected (n=234). As part of this, repeated measures of abdominal adipose tissue and its constituent components were measured via ultrasound to develop and define reliability and reproducibility of a technique to be utilized in practice (n=30). The results from this prospective study, found that parameters of maternal body composition early in pregnancy, in particular abdominal visceral adiposity could be used as a tool to stratify women at risk of developing GDM. This can be used to identify women at risk of GDM early in pregnancy to apply targeted preventative lifestyle interventions. The findings from this thesis can inform future studies in the development develop of an accurate prediction model for GDM in early gestation