Usually, pregnant women with diabetes monitor their glucose during the day using the traditional ‘finger-prick’ test, which can be painful and inconvenient. However, only snapshots of what is happening to the glucose are picked up, as it is only done between four and eight times a day, and not at all during the night when asleep.
Even when these blood glucose readings reach the targets required, pregnant women with diabetes still give birth to large babies. This suggests that the traditional finger-prick test may not be good enough to detect all the changes in glucose that contribute to the baby’s growth, and that using newer technology such as continuous glucose monitoring (CGM) may be able to help with this problem.
The research team, from the University of Leeds’ School of Medicine, has worked out a way to interpret the complex data provided by CGM devices, so they get a much clearer picture of the glucose control across the 24-hour day that is associated with having a large baby.
The devices usually consist of a tiny probe that sits just under the skin and a small data monitor that sits on the skin (about the size of a 50p piece), measuring glucose levels all day, every day, revealing in detail glucose changes that may otherwise be missed with finger-prick testing alone.
Dr Eleanor Scott, Consultant in Diabetes and Endocrinology, who led the research with Dr Graham Law, Senior Lecturer in Statistical Epidemiology, said: “The reality is that comparing the data provided by a CGM to that offered by a finger-prick test is like comparing an image under the microscope to that seen by the naked eye – we get much more detail with CGM.
“Women can use this data to make sure that the times of day when glucose seems to run higher are periods where they are particularly careful to keep their glucose as close to normal as possible. They can do this by consulting with their ‘diabetes in pregnancy’ clinical teams who will be able to advise on timing of insulin, timing and types of food to help smooth the glucose profiles and avoid these problem areas.”
Dr Scott added that the next stage of the research would be to find out how its findings may help with the future design of the so-called “artificial pancreas”, the closed loop insulin systems which are being developed to transform the care of people with type 1 diabetes who are reliant on insulin.
They consist of an integrated CGM sensor and insulin pump that talk to each other via computer to deliver insulin safely across the 24 hour day.
Dr Anna Secher, of the Center for Pregnant Women With Diabetes in the Department of Endocrinology at the University of Copenhagen, a collaborator on the study with the University of Cambridge, said: “CGM has been used for many years in The Center for Pregnant Women with Diabetes in Copenhagen, but this study is the first to investigate glucose levels ‘round the clock’ in relation to large babies.”
The research has been published in the journal Diabetes Care.
The research paper, “Analysis of Continuous Glucose Monitoring in Pregnant Women With Diabetes: Distinct Temporal Patterns of Glucose Associated With Large-for-Gestational-Age Infants,” by Law et al, is available from the University of Leeds press office.
A case study, of a woman who used continuous glucose monitoring during her pregnancy, is available.
Dr Eleanor Scott is available for interview. Contact Ben Jones in the University of Leeds press office on 0113 343 8059