Dr Hilary is joined by Rebecca Fyfe, the woman who lost four stone when pregnant
Rebecca is a mum of seven children who went through pregnancies while obese, weighing 19st 6.5lbs at her heaviest.
After piling on the pounds to reach a hefty 20 stone, she had been told by doctors that having another baby could kill her.
But when she was three months pregnant with her seventh child, Rebecca embarked on a carefully-planned diet, losing four stone before she gave birth - and going on to lose a total of ten-and-a-half stone.
This time Rebecca suffered no high blood pressure or hip pain and had much more energy.
Join the debate
We’ve been asking for your thoughts and tips on Facebook and here are some of your comments so far:
Aimee Pollard: Eat a balanced diet!
Kelsey Nyahs Mummy Lintern: Don't eat for two! Swimming is a great exercise for pregnant women.
Marie Chapman: I did aqua-natal for the last 8 weeks of my pregnancy. The only other exercise I did was lots of walking. I ate in phases, sometimes I'd be starving, sometimes I'd eat very little. I just tried to keep everything in moderation.
Stacey Hughes: I did lots of walking and didn’t eat for two!
Nikki Bark: I had twins 7 months ago and 5 kids altogether - eat little but often, drink plenty of water. Walking and swimming are also fantastic during pregnancy.
Ann Rogers: Just be sensible...you’re not eating for two, but you are feeding another life. Keep to a balanced diet and try a little exercise.
Jill Summers: Just carry on eating a normal healthy balanced diet, with a comfortable level of exercise. I was surprised how good it felt to get into a pool for a few gentle lengths and a float around!
What did you do during your pregnancy? What advice were you given and what would be your best tip for expectant mothers? Share your tips below.