A cohort study of gestational diabetes mellitus and complimentary qualitative research: background, aims and design.

Background: Women with gestational diabetes mellitus (GDM) and their offsprings are at increased risk of future type 2 diabetes and metabolic abnormalities. Early diagnosis and proper management of GDM, as well as, postpartum follow-up and preventive care is expected to reduce this risk. However, no large scale prospective studies have been done particularly from the developing world on this aspect. The objective of this study is to identify and follow a cohort of pregnant women with and without GDM and their offspring to identify determinants and risk factors for GDM, for various pregnancy outcomes, as well as, for the development of future diabetes and metabolic abnormalities.

Methods: This is a prospective cohort study involving pregnant women attending prenatal clinics from urban, semi-urban and rural areas in the greater Chennai region in South India. Around 9850 pregnant women will be screened for GDM. Socio-economic status, demographic data, obstetric history, delivery and birth outcomes, perinatal and postnatal complications, neonatal morbidity, maternal postpartum and offsprings follow-up data will be collected. Those diagnosed with GDM will initially be advised routine care. Those unable to reach glycaemic control with diet alone will be advised to take insulin. Postpartum screening for glucose abnormalities will be performed at months 3 and 6 and then every year for 10 years. The offsprings will be followed up every year for anthropometric measurements and growth velocity, as well as, plasma glucose, insulin and lipid profile. In addition, qualitative research will be carried out to identify barriers and facilitators for early GDM screening, treatment compliance and postpartum follow-up and testing, as well as, for continued adherence to lifestyle modifications.

Discussion: The study will demonstrate whether measures to improve diagnosis and care of GDM mothers followed by preventive postpartum care are possible in the routine care setting. It will also map out the barriers and facilitators for such initiatives and provide new evidence on the determinants and risk factors for both GDM development and occurrence of adverse pregnancy outcomes and development of future diabetes and metabolic abnormalities in the GDM mother and her offspring.