Kelly Jennings is meticulous about what she eats during pregnancy, but she wasn't always so careful.
The 34-year-old, from Blenheim, has three children and is expecting another in three weeks.
She said that because her first pregnancy was a surprise, she had not altered her diet nor sought advice on healthy eating when she conceived.
"I didn't focus much back then, I didn't have time to plan these things. Fourteen years ago there wasn't as much information as I get now."
She didn't seek healthy eating advice until months into her pregnancy.
"Now I'm on multi-vitamins, folic acid and I've cut out caffeine and everything they don't recommend, which is quite a long list now. I do certainly watch the things I'm eating."
Ms Jennings said she had never chosen to diet herself, but pointed out that many women go on aggressive diets before conceiving.
"A lot of people want to get their body into shape before they get pregnant. I guess sometimes, like in these studies, they're doing more hindrance."