When Amrita Naidu was pregnant with baby Aarav she had to cut back on rice and roti, and eat more vegetables.
The 30-year-old South Aucklander, a Fijian-Indian, was diagnosed with pregnancy-related diabetes while she was carrying Aarav, her first child.
Around 8 per cent of pregnant women in New Zealand are diagnosed with the condition, called gestational diabetes and detected through blood samples bearing elevated sugar levels.
Aarav is a healthy boy, but a mother's gestational diabetes can put a baby at risk of a range of problems, including being born abnormally large and suffering jaundice and breathing difficulties. As they grow up, they are at increased risk of becoming obese and developing diabetes.
For mothers, the condition raises their risk of type 2 diabetes and heart disease.
Diabetes involves problems with processing sugar.
Amrita joined a study comparing New Zealand's blood-sugar threshold for gestational diabetes diagnosis with a lower one used in other countries. Researchers at Auckland University's Liggins Institute will compare health outcomes for mothers and their babies.
"I was motivated to take part because I have quite a family history of diabetes - my parents, my dad's brothers, my grandma and some other extended family members as well," Amrita said.
She was given advice on diet and exercise, and put on the diabetes drug metformin until her labour started.
Amrita said her weight, now 67kg, was in the normal range, but she was a little overweight when she conceived.
The dietary advice involved eating more frequently - five times a day instead of three - and reducing portion sizes.
"If I usually had three roti in the morning I had one and a half instead and increased my intake of milk and vegetables to balance it out."
She said these changes have persisted "a little bit - sometimes I'm tempted to eat stuff, to cheat, but I try not to".
The leader of the study, Professor Caroline Crowther, said there had been calls internationally to use a lower threshold for deciding a woman had gestational diabetes and some countries now used that threshold.
"What this study will do for the first time is carefully compare our current threshold in New Zealand to the lower international threshold, so we can see which is better for reducing the short and longer term problems for the mother with GDM [gestational diabetes mellitus] and her baby."
Amrita said she found the study helpful. "If someone asked me if they should take part, I would say 'definitely'. You find out things about yourself and your diet."
More than 700 women have taken part in the study. The researchers want 9000 in total and are inviting women to consider joining.
They want women who are between 24 and 34 weeks pregnant with one baby, who do not have diabetes or a history of gestational diabetes and who are planning to give birth at Counties Manukau or Auckland District Health Board facilities.
What is gestational diabetes
• A form of diabetes that can occur during pregnancy
• Involves a build-up of sugar in the blood
• Normally insulin helps move blood-sugar into muscles
• Pregnancy hormones can stop insulin working well
• Effects on the baby can include being born abnormally large, and increased risk of obesity and diabetes in later years
• The mother is at increased risk of pregnancy complications
• The condition usually goes away following pregnancy but leaves an increased risk of later development of type 2 diabetes