Following a smooth pregnancy with her first child, Katie Duggan was shocked to be told during her second that she had gestational diabetes.
The diagnosis, when she was five months’ pregnant with her daughter Maisie, came after a routine urine test. Katie, concerned about the health of her unborn child, burst into tears.
‘It didn’t make sense because I exercised regularly, was a healthy weight and ate well,’ she says.
In fact, it’s not unusual for women who are slim and healthy to be diagnosed with diabetes during pregnancy. The condition occurs when the body struggles to regulate blood-sugar levels because it stops producing or responding to insulin – a hormone which clears glucose out of the bloodstream.
Type 2 diabetes is normally linked with lifestyle factors such as obesity. But it can also develop when pregnancy hormones interfere with normal blood-sugar control. This gestational diabetes usually resolves after the baby is born.
Katie was instructed to follow a low-carbohydrate diet and prescribed the diabetes drug metformin. But her blood-sugar levels remained high.
A further blood test revealed that she was actually in the early stages of type 1 diabetes, which is caused by the body’s immune system mistakenly attacking insulin-producing beta cells in the pancreas. In type 1, the body eventually stops producing insulin, leaving those affected dependent on insulin injections or pumps for life. Katie was prescribed insulin to stabilise her blood sugar during her pregnancy and was told she would need the drug permanently at some stage.
She explains: ‘My blood tests found that I have four antibodies for type 1 diabetes, which meant I was developing the condition.
Katie Duggan was shocked to be told that she had gestational diabetes she was five months’ pregnant with her daughter Maisie
In type 1 diabetes, the body eventually stops producing insulin, leaving those affected dependent on insulin injections or pumps for life
‘Scared and upset, all I cared about was making sure my baby was safe.’
Up to half of women who are diagnosed with gestational diabetes go on to develop type 2 diabetes within five years.
However, there is no such link between gestational diabetes and type 1 diabetes. The causes of type 1 are unclear, but genes, viral infections and environmental triggers contribute.
Doctors said that Katie would have been already developing early-stage type 1 when she became pregnant: pregnancy hormone changes made her blood-sugar control worse. The diagnosis changed her life.
Katie, 34, a solicitor, who lives in Manchester with her husband Adam, 30, also a solicitor, and daughters Annabelle, nine, and Maisie, three, says: ‘I was on a very restrictive low-carb diet and I had to set several alarms to remind myself to inject insulin at various times in the day.’
Lucy Chambers, head of research communications at charity Diabetes UK, says: ‘Living with type 1 diabetes is relentless. It requires continuous decision-making and attention without ever being able to switch off.
‘People must closely monitor their blood-sugar levels day and night to avoid dangerously low and high levels, and calculate insulin doses – adjusting for what they’re eating, as well as exercise, hormone levels, illness, stress and other factors.’
But now there are several new treatments and tests, which it is hoped could halt the progression of type 1 diabetes and even end the need for patients needing insulin. Last month, the immunotherapy drug teplizumab, which is given as an injection, was approved for use on the NHS in adults and children aged eight and above with early-stage type 1 diabetes.
Teplizumab works by attaching to proteins on the surface of the immune cells which are responsible for attacking insulin-producing beta cells and has been shown to stop the condition from worsening.
In a UK trial, children and adolescents recently diagnosed with type 1 diabetes who were given the drug maintained the same levels of insulin after 78 weeks, while those who received placebo injections produced less, indicating that their type 1 had progressed.
Previous research suggests that immunotherapy can delay the progression of type 1 diabetes by an average of three years if it is given in the early stages of the disease, which often develops in childhood and early adolescence.
These drugs retrain the immune system so it doesn’t attack beta cells – so people can still produce some of their own insulin – but they need to be administered before too many beta cells are destroyed. Currently, immunotherapies are being trialled in the UK in newly diagnosed children aged one and over. Typically, by this point, only 20 to 30 per cent of beta cells remain.
Those treated with immunotherapy would still need insulin injections. However, preserving some of their own function will eventually mean insulin ‘and the whole burden of self-managing the condition’ are no longer necessary, says Lucy Chambers. It may even ultimately prevent the condition entirely.
Identifying people at an early stage – which can be months or years before classic symptoms of thirst, frequent urination and fatigue – is challenging.
At the moment, you are unlikely to be tested without a strong hereditary link, says David Hodson, a professor of diabetic medicine at Oxford University.
‘There is a hurdle to overcome about how we screen a whole population of adults,’ adds Rachel Connor, from the charity Breakthrough T1D.
One solution might be a new blood test which detects islet autoantibodies – markers in the blood which indicate that the immune system attack on the beta cells has already begun.
The blood test is already being used to screen children for type 1 diabetes as part of a study led by Birmingham University.
Lucy Chambers, head of research communications at charity Diabetes UK, says living with type 1 diabetes ‘requires continuous decision-making and attention’
Launched in 2022, initial results, published recently in The Lancet Diabetes and Endocrinology, found that 235 of the 17,283 children, aged three to 13 without known type 1 diabetes, had at least one autoantibody. This showed they were at increased risk of developing type 1 diabetes or were in the early stages. Some were then offered immunotherapy. The next trial phase will test children aged two to 17.
Other research, led by Bristol University, aims to find the number of autoantibodies which predict the risk of type 1 diabetes in adults.
In Katie’s case, although her blood-sugar levels returned to normal after Maisie was born, enabling her to come off insulin, her early type 1 diagnosis meant she could continue monitoring them through a sensor stuck to her skin.
This was fortuitous, she says: ‘I hadn’t had any obvious symptoms so without the sensor I’d have been none the wiser.’
When her blood sugar began spiking early last year, a specialist recommended immunotherapy. It was given intravenously for 30 minutes on 14 consecutive days in September.
Since then, Katie’s time ‘in range’ – the proportion of time her blood sugar levels were at a safe level over 24 hours – has increased from a low of 70 per cent to 90 per cent. A ‘safe’ range is 70 per cent and over. Katie says: ‘It’s blindingly obvious that immunotherapy made a difference. I feel so much better and have more energy. It’s given me extra time without needing insulin and time to educate myself about living with a complex disease.’
It is hoped that immunotherapy could become part of a ‘cure’ for type 1 diabetes, alongside another innovation – islet cell transplant, using islet cells from deceased donors.
Transplants, which are infused, are already offered on the NHS but few donor cells are available. The solution may be lab-grown beta cells, derived from donated stem cells (master cells that can turn into other cell types).
Data, presented to the American Diabetes Association’s 2023 conference, showed that six people with type 1 diabetes who couldn’t make their own insulin were able to produce it effectively again following the treatment. Some could even stop insulin completely.
However, a transplant can trigger an immune response. This means the patient requires lifelong immunosuppressant drugs which can have side-effects such as increased risk of infection or kidney damage. It is thought that immunotherapy might help to protect the new cells without the need for immunosuppressants.
In the meantime, Professor Hodson points out that an artificial pancreas device offered on the NHS has been ‘transformative’. It continuously monitors blood-sugar levels and releases insulin from a pump when needed.
A 2023 Cambridge University study found that it gave patients three extra hours a day in their target time in range and they experienced better sleep (they no longer needed to wake at night to check and treat blood-sugar levels). The ultimate goal, however, is ‘an insulin-free future’, says Professor Hodson.
