Taking control of diabetes during pregnancy

Marjorie Brennan talks to Dr Amy Herlihy about her experience of gestational diabetes and what can be done to avoid it in pregnancy.

FOR many expectant mothers, pregnancy is an opportunity to take it easy, put their feet up and treat themselves to a sugary snack to alleviate their discomfort.

However, for a growing number of pregnant women, diagnosed with gestational diabetes, such indulgences can be a risk to their health and that of their baby.

Gestational diabetes is caused by too much glucose (sugar) in the blood and is estimated to affect 12% of pregnant women. 

It usually develops in the second or third trimester and disappears after the baby is born, although women who develop it are at an increased risk of developing type 2 diabetes later on.

According to Diabetes Ireland, in 2013, the last year of published birth statistics, approximately 8,600 women had gestational diabetes and of those it is likely that 2,150 will be diagnosed with type 2 diabetes within three years.

While the majority of cases can be controlled with diet and exercise, 10% to 20% of women with gestational diabetes will require insulin. If gestational diabetes is not detected and controlled, it can increase the risk of conditions such as pre-eclampsia and result in birth complications. 

Cases of gestational diabetes are predicted to increase even further due to rocketing rates of obesity, which is one of the risk factors. 

A recent study by the World Health Organisation forecasts that by 2030, 57% of Irish women and 48% of Irish men will be obese.

Dr Amy Herlihy, 35, has had professional and personal experience of the condition. She has three children and was diagnosed with gestational diabetes while pregnant with her eldest son Oscar, now seven.

“It was diagnosed towards the end of the pregnancy. I was put on a strict diet and given extra scans as he was quite a large baby. 

"He was 9lbs 11oz, so I ended up with an emergency C-section, due to failure to progress. He had a hypoglycaemic episode when he was born, from my high sugars.”

While Amy wasn’t overweight and had always had a normal BMI, her father does have type 2 diabetes. Family history of type 2 diabetes increases the risk of gestational diabetes.

Because of her history, on her second pregnancy with Ruby, now five, Amy was screened at 16 weeks. 

“They found that I had it. Again, I was put on a strict diet, checking my sugars seven times a day, and I was scanned every fortnight, to monitor her weight.”

On her third pregnancy, it was presumed inevitable that Amy would have gestational diabetes.

“If you get it once, it’s virtually unheard of not to get it for subsequent pregnancies. On Charlie, my third child, it was almost a foregone conclusion that I would have it. I was checked every two weeks because my doctor was convinced I had to have it.” 

However, Amy defied the odds to remain clear of the condition throughout her third pregnancy, which she ascribes to taking supplements.

“I think it was down to vitamin D and fish oil supplements. I had started my masters in nutritional medicine at that stage, so I had heard lots of good things [about these supplements]. 

"I wasn’t taking them for my two other pregnancies. I started taking them at least six months before I got pregnant with Charlie.”

Amy believes it is important for women who are planning to get pregnant or trying to conceive to take these supplements, along with the currently recommended folic acid.

“A lot of the research, especially on the omega 3s and vitamin D, show they are protective before a woman gets pregnant. 

"There are obviously plenty of reasons to take them, but from a diabetes point of view, you need to be taking them early on to help prevent it.”

Diabetes Ireland, following WHO guidelines, does not recommend taking vitamin D during pregnancy, due to limited evidence of its benefits and harms, and also advises against taking fish oils due to high levels of vitamin A. 

However, Amy continued her supplement regimen with the support of her obstetrician during her pregnancy.

“I do not recommend cod liver oil during pregnancy due to issues with vitamin A,” she says. 

“However, fish oil supplements (Nordic Naturals, MorEpa etc) that I recommend are not sourced from fish liver and do not contain vitamin A.”

Amy, who this year moved from general practice to opening her own clinic in Carrigtohill, Co Cork specialising in pre-natal planning and nutritional consultations for children with special needs, has seen a big rise in cases of gestational diabetes in recent years.

“When we were in college, it was not that common. In general practice now, you would be checking every woman. If you’re overweight, you’re at a higher risk and a high proportion of parents now fall into that category.”

She recognises that the subject of someone’s weight is a delicate one that needs to be handled tactfully and in a supportive manner.

“It’s very delicate and, even when not pregnant, no woman wants to be told they need to lose weight. When someone is pregnant, you don’t want them going on a calorie-restrictive diet, you want them to be healthy. 

"It’s not about unrealistic goals... Get someone to make small changes. When you’re on a second or third pregnancy and have small kids, it can be hard not to be overweight.”

Amy recommends that if someone is planning a family, the best thing is to look at diet and exercise now. 

“I would never tell someone to postpone getting pregnant, but if you know you are going to start trying, start the folic acid, vitamin D, omegas and probiotics now and get yourself as healthy as you can beforehand.”


A recent study, published in the journal, BJOG: an International Journal of Obstetrics and Gynaecology, found that exercise during pregnancy can reduce the risk of developing gestational diabetes.

Spanish researchers looked at the impact of exercise during pregnancy on gestational diabetes, encompassing 13 trials involving more than 2,800 women.

They found that women who usually did little or no exercise, but who then undertook an exercise programme during pregnancy, reduced their risk of developing gestational diabetes by 36%.

The researchers stated: ”Exercise is not something to be feared during pregnancy — the moderate levels of exercise used in these studies had significantly positive effects on health and were found to be safe for both mother and baby.”

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