Tips for a safe workout during pregnancy

As long as your pregnancy is going well, exercising is great for you and your growing baby (Morris and Johnson 2005). Just make sure your regime is fairly easy-going and doesn't involve any jolts or falls. And it won't just benefit you now. Staying fit may help you to cope with the demands of labour and birth, when the time comes (Clapp et al 2002, Berk 2004, Hatch et al 1998).

Which activities are best for me?

Activities such as swimming, walking, yoga and Pilates, and low-impact aerobics are good choices. Pregnancy is not the right time to start any new intensive exercise, but it is safe to continue with most types of exercise if you're used to them.

While you're pregnant, the hormone relaxin gets to work, softening up the tough, flexible tissues (ligaments) that connect your bones. Relaxin loosens up your pelvic joints, ready for your baby's journey into the world. Even if you're normally quite supple, the effect of this hormone is to make you more prone to sprains and other injuries (Artal et al 2003). That's why it's important to pick the right activity.

Which sports should I avoid?

Because your joints are looser than normal, it's best if you don't do any activity that could make you slip or fall.

Vigorous or extreme activities such as horse riding, skiing, mountain climbing are out. They carry too high a risk of injury to your tummy. You should also avoid most contact sports, such as football, basketball and so on. Finally, give racket sports a miss if you're not a regular player, as they can be tough on your knees and ankles (Artal et al 2003, Davies et al 2003).

Should I have a check-up before starting exercise?

If you have always been active, you can probably carry on with your usual exercise routine. That's as long as you haven't developed any complications in your pregnancy. That said, it can't hurt to check with your midwife or doctor to make sure your choice of exercise is right for you. If you've never been the sporty type, they can give you some tips to help you get started.

What should I wear?

Wear layers of light clothes that are easy to peel off when you need to (Lynch et al 2003, Soultanakis-Aligianni 2003). It's important to make sure you don't overheat while you exercise, especially in the first trimester. We can't say for sure that your baby will be harmed if you get too hot, but it's best to be cautious. Your temperature (taken under your arm) should be less than 39.2 degrees C after exercising.

Make sure your maternity bra is comfortable. Get one that fits now. If you leave room to grow into your bra, it won't give you enough support.

You'll also need trainers that fit your feet properly to help support your ligaments and tendons. If your shoe size has changed because of mild swelling, you may wish to buy a new, more comfortable pair.

Any tips for a good workout?

Get in the habit

If you're committed to keeping fit, do so on a regular basis. It's best to exercise at least three times a week, for at least 30 minutes at a time (Hegaard et al 2007). Make sure you have a couple of rest days during the week.

Try to achieve a balance. Exercising five times a week or more may increase the chance of you having a baby with a low birth weight (Campbell and Mottola 2001). On the other hand, working out only occasionally may make you more prone to injury. And you won't benefit from exercise by doing it only once in a while.

Warm up before exercising

Warm-ups do just that. They warm up your muscles and joints ready for activity and help build your heart rate slowly. If you skip the warm-up and jump around before your body is ready, you may injure yourself (Fradkin et al 2006).

Keep moving

Standing still for long stretches can decrease blood flow to your uterus (womb) and cause blood to pool in your legs. This can make you dizzy (Schneider et al 2005). Some yoga and dance positions involve being still. So if you feel uncomfortable, change positions, or walk on the spot.

Don't exercise lying flat on your back after the first trimester

Besides being uncomfortable, this position may cause dizziness. It puts your uterus squarely on top of the vena cava, a major blood vessel, and this may reduce blood flow to your brain and uterus (Ueland and Metcalfe 1975, Scott and Kerr 2005). Prop yourself up on your elbows instead, or lie on your left side.

Take care with awkward positions

The following may cause ligament strain and pain in and around your pelvis:

• sit-ups
• standing on one leg
• separating your legs widely

You can tone the muscles used in these movements in other ways. Swimming and walking will work your thigh muscles (quadriceps) and buttocks just as well as lunges and knee bends.

Your centre of gravity shifts during pregnancy. That's why you should take care when you shift positions. Getting up quickly can make you dizzy, and cause you to lose your footing and fall.

Drink lots of water

Try to drink about two glasses of water two hours before you begin exercising. Take a sports bottle of water with you when you exercise and take frequent sips from it. It's important you don't become dehydrated. This may raise your body temperature, which may not be good for you or your baby.

Take it easy when it's hot and humid outside. Weather like this makes you prone to overheating. Give your workout a miss or exercise indoors in a cool, airy room.

Cool down

Walk on the spot for a few minutes or stretch. It gives your heart a chance to return gradually to its normal rate.

I like to feel the burn. Is this safe?

Don't exercise to exhaustion. You may be used to monitoring your heart rate while exercising, but this won't help you while you're pregnant. Heart rates can vary widely in pregnancy (Wolfe and Weissgerber 2003, Artal et al 2003, Collings et al 1983).

A good rule of thumb is to slow down if you can't comfortably carry on a conversation. See our pregnancy exercise guide for more information about how hard you can exercise.

Listen to your body. When something hurts, that's your warning sign, so stop. You should feel that you're working your body, not punishing it.