Gestational diabetes develops earlier than expected, says study. But early tests and treatment can help both mother and child

What is gestational diabetes and why does it lead to complications?

It is a form of diabetes that women develop during pregnancy when levels of certain hormones such as human placental lactogen and cortisol increase. These hormones lead to cells becoming more resistant to the glucose-lowering hormone insulin. When the body cannot keep up with the increased need for insulin during pregnancy, women get gestational diabetes.

This type of diabetes self-corrects after the child is delivered and the hormone levels go down.

Diabetes during pregnancy – whether it is pre-existing or developed during gestation – can lead to the babies growing larger. The bigger babies are more likely to get stuck in the birth canal, come out shoulder first instead of head, go into respiratory distress resulting in ICU admission and cause trauma in the vaginal area for the mother.

Half the women enrolled in the study were treated for early gestational diabetes – occurring during the first trimester – while the other half were just followed up like regular mothers and were treated for gestational diabetes only in the second trimester.

The study group comprised 30 per cent people of Asian descent, including participants from India.

Why is early detection important?

Explained Dr Mohan, “It was generally accepted that women developed gestational diabetes only in the second trimester after their hormone levels changed. But for some time now we have been seeing early gestational diabetes even in the first trimester. Now, the question is, even if we detect it, should we treat it? The question was whether early treatment would improve outcomes or lead to more complications. And this study provides the answer clearly.”

The study showed that early treatment of gestational diabetes – before 20 weeks – reduced these complications to the mother and child by 5.6 percentage points – from 30.5 per cent to 24.9 per cent.

“Over one in 20 babies avoided a group of severe birth complications, including birth damage like broken bones or nerves, or getting stuck during birth known as shoulder dystocia. In addition, breathing problems requiring oxygen were almost halved and the number of days needed in neonatal intensive care or special care units went down by 40 per cent. Furthermore, severe damage to and around the mother’s birth canal, known as perineal injury, was reduced by over three quarters,” the lead study author from the Western Sydney University, Professor David Simmons, said in a release.

How is gestational diabetes diagnosed? And, how can doctors differentiate between pre-existing diabetes and gestational diabetes?

“If someone does not have diabetes and develops it during pregnancy, it is termed as gestational diabetes. The problem is many people do not know that they have diabetes before a pregnancy, especially in India, where people tend to get the disease at a younger age,” said Dr Mohan.

As per the current norms, he said, an oral glucose tolerance test is done in the second trimester to detect gestational diabetes. To diagnose early gestational diabetes – and differentiate it from pre-existing undiagnosed diabetes – two tests are required in the first trimester. A fasting blood glucose test to check whether the sugar levels are elevated and an HbA1c test to check the average blood sugar levels over the past three months. “For the people with pre-existing, undiagnosed diabetes, the HbA1c levels will also be high along with high sugar levels in the fasting glucose test,” said Dr Mohan.

Depending on blood sugar levels, doctors can prescribe diet and exercise, oral pills or even insulin to treat gestational diabetes.

Dr Mohan says other studies by his centre have also shown that those who develop gestational diabetes early on are likely to have a more severe form. “This could be because they are likely to have more risk factors – stronger family history of diabetes, obesity – and hence they develop the disease quicker than others. It could also be that the mechanism of diabetes in the women who develop diabetes in the first trimester is different because they get it even before their hormone levels have changed much,” said Dr Mohan.

Why does it matter?

It matters because mothers who get gestational diabetes are much more likely to develop diabetes a few years later. “What we have seen is that the people who develop gestational diabetes are also likely to convert to diabetes early on – within one of two years of delivery as compared to three to four years among those with conventional gestational diabetes,” said Dr Mohan.

His team has been trying out various methods to ensure that mothers with gestational diabetes remain in follow-up so that the onset of diabetes can be delayed as much as possible. “What we have seen is mothers are unlikely to change their diet or exercise during the first six months when they are breast-feeding, but we try to get them to follow up after that and encourage them to lose weight, eat better, and exercise to delay the onset of diabetes,” he said.