Tempting though it may be to spend nine months with your feet up in front of the telly  eating for two, it really is better for both you and your baby to stay fit.

So, what's the best kind of exercise to take as the months go by and the bump gets bigger?

Gentle and regular is good to begin with. Try and walk (wearing sensible, supportive shoes) or go swimming (the weightlessness you feel in water is particularly relaxing) for at least half an hour a day, most days of the week.

Women who are used to running or jogging may find that they are comfortable keeping the routine going well into pregnancy; our own champion athlete Paula Radcliffe was still running 14 miles a day when she was five months pregnant with her second baby but don't try this at home, girls, unless you've got a gold medal or two beneath your ever-expanding belt.

Don't forget to stay out of the heat while exercising and always drink lots of water. You sweat much more when pregnant so you can easily get dehydrated.

Besides the cardiovascular benefits derived from walking, running or swimming Yoga and Pilates are effective exercise programmes for strengthening the core conditioning system and developing breathing techniques that may help during labour. Meanwhile stretching is effective for building both flexibility and strength.

A little word of warning: don't exercise flat on your back, particularly after 16 weeks, because your bump presses on your blood vessels and it can make you feel faint.

Exercising while you are pregnant will help you avoid getting constipated (a common and miserable hazard of pregnancy) and staying supple while you are pregnant will help you, both during labour birth and after the baby is born. And though you may feel that you'll never again fit into those pre-pregnancy, skinny jeans, by keeping in shape now you'll stand a much better chance, post-natally, of losing any extra weight quickly and easily.

There is no hard and fast rule about how much you can exercise. Like non-pregnant people, pregnant women should do as much as they feel comfortable with. Paradoxically exercise will help overcome tiredness and improve circulation but if you have any questions or qualms about what you're thinking of doing, consult your doctor first.

Note: If, in your newly-pregnant state, you suddenly think that now is the time to have a go at kick-boxing, skiing or maybe a spot of Parkour-style leaping across high buildings, think again.