My friends and family think I’m bonkers. Despite being eight months’ pregnant, I’m still doing regular exercise classes at the gym. For one thing, I don’t want to let myself go. My stomach’s circumference might rival that of one of those new planets they have just discovered, but I still want to show off toned arms and legs next to my cumbersome torso. And I spent too much of my youth being out of shape to want to scupper all my good work now.

So throughout pregnancy I have been attending aerobics and Body Pump classes at my local Virgin Active gym in Holloway, north London.

In the former, I walk through the moves rather than running and jumping with everyone else, but it still gets me moving and I can join in with the hand weights section. The latter activity sees me lifting barbells to music — lunging, squatting, chest pressing, rowing, tricep dipping and bicep lifting — all the while avoiding my bump and trying to keep myself from overheating.

The process has made me feel energised and gives me the sense that I can still be fit and toned despite pregnancy.

My “pump” teacher Idi Arewa has noticed that a lot more pregnant women are exercising these days. “There’s that fear that after the birth you won’t be able to regain your former shape. If you have been active during pregnancy, your muscles are strengthened which makes labour easier and afterwards your stomach will bounce back faster.”

While 30 years ago pregnant women were advised to take it easy, recent research suggests that exercise throughout pregnancy can benefit mother and child. German scientists reported that running while pregnant can enhance development of the foetus.

Other studies have shown that babies born to active women tend to be more alert and are less inclined to be overweight toddlers. I had been doing fitness classes for at least a year before pregnancy (and have been generally active for much longer) so I’m not starting to exercise for the first time while pregnant — something that is not advised. “If your body is not used to something and you’re suddenly bringing up your heart rate by running or jumping, it’s not a good idea to start when you’re pregnant, particularly as your body is already dealing with massive changes,” warns Arewa.

But she does agree that you should not give up your pre-pregnancy regime and spend nine months curled up in front of the TV with a packet of biscuits. If you are not used to exercise, she suggests walking, or even better, swimming, which is “fantastic, especially during the later stages of pregnancy because there’s no impact at all and it still gives a good workout”.

She does warn that you might get a false sense of your abilities. “Hormones released during pregnancy make you feel good and you might try to be more active particularly in the second trimester, so make sure you don’t over do it,” she says. “You also produce a hormone called relaxin which makes you more flexible. But again, be careful as you might overstretch yourself and damage a ligament.”

Body Pump is a particularly good exercise for pregnant women as it is low impact but it is not static — making it a good cardio workout. “You can monitor your own weights without having to pile them on,” says Arewa. “It engages your abdominal muscles and as your abdominal walls are attached to the pelvis it will make the labour a lot easier.”

Arewa adds that you should listen to your body while exercising as pregnant women do have the tendency to overheat. She advises taking regular breaks and drinking plenty of water.

That said, experts tell us that not only is it a good idea to exercise while carrying a child, but that pregnancy can actually enhance performance. In the first three months, a woman’s body produces a surplus of red blood cells which are rich in the oxygen-carrying haemoglobin to support the growing foetus. Applied sport and exercise science professor at John Moores University Greg Whyte says this could enable a woman to run, cycle or swim for longer. He also notes that the increase progesterone, oestrogen and testosterone in pregnancy could increase muscle strength.

Runners Paula Radcliffe and Liz McColgan, and golfer Catriona Matthew, all claim that the rigours of pregnancy and childbirth made them stronger of body and of mind, thus improving their athletic powers.

I just can’t wait to find out how much more energetic I am after December when I become a mum.