What causes leg cramps?
Leg cramps - painful spasms in the leg - affect as many as 50 per cent of pregnant women. No-one knows exactly why it should be so common in pregnancy but its occurrence especially in the later months suggests that the extra weight you are carrying puts pressure on the blood vessels and nerves into the leg.
Another popular belief is that it is symptomatic of being deficient in certain nutrients - calcium, magnesium or potassium - but do not take this as an indication that your baby is lacking substantially in these nutrients and don't increase any supplements you might already be on. Instead, leg cramps, like breathlessness and heartburn, is one of the physical misfortunes of later pregnancy which affect you and not your baby.

How can it be avoided?
Make sure you keep up your calcium intake and find natural sources of magnesium. Many people recommend eating bananas to up their potassium intake. Some theories have it that an excess of phosphorus can bring on cramps, so try to avoid too many very meaty or fast food meals.
Keep yourself hydrated.
Leg cramps often strike at night or as you wake and take the first stretch of the morning. Try doing small leg stretches and ankle circles before going to bed to 'warm down' before hours of inactivity. When you wake in the morning, give your calves a good warming rub before an attack strikes.
Rest with your feet up.
Some people believe that wearing support tights can help with the problem. Certainly you should try to keep your legs warm and might want to try leg warmers on colder nights/early mornings.

If you get a leg cramp attack
Milder attacks can be dealt with by standing up and stretching out your leg, lifting your leg up so your toes are stretching and pushing against the floor. You can try walking around in this position (a cold floor can help) or lean against a wall to do this. If you are heavily pregnant, you will not be able to reach out and pull your foot or toes towards you as you might when you get cramp at any other time. In this instance you should ask your partner or another adult for help as a bad attack may not be alleviated by small stretches.
When the attack has passed, warm the area by rubbing and massaging it gently.