Diabetes, fetal growth and stillbirth

Diabetes affects 1-2% of pregnancies and is a major risk factor for many pregnancy complications. Women with diabetes are around five times more likely to have stillbirths, and three times more likely to have babies that don’t survive beyond their first few months.

Diabetes can also stop babies from growing normally – they are born either too small (fetal growth restriction (FGR)) or too large (macrosomia),  both of which dramatically increase the risk of stillbirths.

Babies who do not grow properly in the womb – whether too large or too small – are also at risk of serious health conditions later in life, such as obesity or diabetes. High blood glucose levels are associated with abnormalities in fetal growth, but the relationship between blood glucose levels at different stages of pregnancy and how this relates to the development and function of the placenta is poorly understood.

Several of our previous study participants have voiced frustration that, despite their best attempts at glucose control, their babies have not grown normally. This prompted us to set up the VELOCITY clinic, a specialist research clinic to more closely examine how babies grow during a pregnancy complicated by maternal diabetes.

Fewer small blood vessels to transfer nutrition and oxygen

We have recently found that the distribution of sizes of blood vessels is different in placentas from women with diabetes compared to women without diabetes.

Our initial research shows that there are more large vessels in placentas affected by diabetes, and less of the smaller vessels – this is very important as it is the small vessels that transfer of nutrients and metabolic waste between the placenta and the baby.

Ongoing work will determine the relationship between blood glucose control in the mother and the different types of blood vessels in the placenta.

104/250 women have been recruited to date. The clinical part of the project is progressing well with continuous blood glucose monitoring data collected on all participants at 2-5 time points. 50 placentas have been collected, 28 of which have been investigated using casting and the remainder banked for future histological analysis.

Timing

2016-2019

Research papers

• Dempsey, A; Johnstone, E; Chmiel, C; Marshall, G; Horn, J; Myers, J; Longitudinal placental growth factor (PlGF) in pregnancies complicated by pre-existing diabetes in the context of maternal hypertensive disease. 2017 BJOG-An international journal of obstetrics and gyaecology 124 105-105
• Hakim, Matina; Aplin, John; Greenwood, Susan; Lowe, Tristan; Myers, Jenny; increased placental venous vessel diameters in pregestational diabetes. 2018 PLACENTA 69 E12-E13

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