It's safe to do most forms of exercise in pregnancy, and far better for you and your baby than not doing any exercise at all.
But you will need to make adjustments in pregnancy. As your baby grows, your sense of balance and posture alters. Your body works harder to give enough oxygen to your baby, so you may feel less energetic, and tire more quickly. Your joints may also be more vulnerable to strain due to the hormones that your body produces.
Listen closely to your body, so you know when you’re working yourself too hard. As a rule of thumb, try not to get so breathless that you can’t keep a conversation going while you’re exercising. Getting slightly sweaty is fine, but never exercise to the point of exhaustion, as this is a sign that you and your baby are getting less oxygen.
When should I call my midwife or doctor?
If you have any of the symptoms listed below either during or after exercise, are worried about a new symptom, or you just don’t feel right, call your midwife or doctor.
On recognising these signs, don't stop abruptly, as you may feel faint. Instead, walk around slowly for a little while, or continue transferring your weight from one foot to the other, by lifting one heel and then the other. This will bring your heart rate down slowly. Have some water and go somewhere cool before seeking help.
1. Dizziness
Mention it to your doctor or midwife if you feel dizzy during or after exercising. If you have headaches or heart flutters (palpitations) at the same time as feeling dizzy, it may be sign that are dehydrated, or that you haven’t got enough iron in your blood (iron-deficiency anaemia).
2. Heart palpitations
If you feel strange, fluttery sensations in your chest, you may be exercising too hard. Slow down gradually until you come to a stop, and tell your doctor or midwife.
3. Pain in your back or pelvis
Hormonal changes affect the ligaments that normally support your joints, making them looser and less stable. This makes you more likely to be injured. See your doctor or midwife if you have back or hip pain, or any pain in either the front or back of your pelvis.
4. Nausea or vomiting
If you feel sick while exercising, or vomit, you are overdoing things. Slow down and don't exhaust yourself. It could also mean that your blood sugar levels are low, or that you have low blood pressure.
Make sure you eat a small snack before you exercise. And if you are doing a lot of exercise, make sure that you eat enough calories to compensate for this. See our healthy snack suggestions.
5. Sudden change in body temperature
When you exercise, your body temperature increases. If your hands turn clammy, or you get hot or cold flushes, your body is having a hard time regulating its internal thermometer. This may be harmful for your baby in the first trimester.
If you overheat, your baby may overheat, too. Your body will try to cool itself by diverting some of the blood flowing from your uterus (womb) to your skin’s surface instead. This will result in you turning a red or pink colour and sweating more.
Drink plenty of water before and during exercise to prevent overheating. Keep exercise sessions to no longer than 45 minutes, and avoid exercising in very hot or humid weather.
6. Swelling
Your feet and hands may puff up a little after exercise, but if the swelling is worse than usual, see your doctor. Sudden, severe swelling in the second half of pregnancy can be a sign of pre-eclampsia, which causes your body to hoard fluid, and your blood pressure to rise. It restricts the blood supply to the placenta and, if left untreated, can be harmful to your unborn baby.
When should I seek urgent help?
The symptoms listed below are potentially more serious. If you have any of them, and you can’t get to see your doctor or midwife, don’t wait around. Go to an antenatal day assessment unit, call your hospital’s maternity unit, or go straight to accident and emergency.
7. Leaking fluid from your vagina
If you're leaking fluid from your vagina, it's possible that your waters have broken. Some of the amniotic fluid that surrounds your baby in your uterus (womb) may be escaping.
It’s easy to confuse this with leaking a little wee (stress incontinence) while you’re exercising, but see your doctor or midwife to be sure. Doing regular pelvic floor exercises will help to prevent leaks.
8. Calf pain
If you have a sharp pain, swelling or redness in your calf, it may be a sign that a blood clot has lodged in a deep vein in your leg (thrombosis) . It’s crucial to have it checked as soon as possible, as this can travel to your lungs or brain.
9. Blurred vision
If your eyesight gets blurry in the middle of exercising, you may be dehydrated, or your blood sugar levels may be too low. Make sure you eat a snack beforehand, and drink plenty of water before and during exercise.
Not having enough fluid in your body can make your blood pressure drop and your heart work extra hard. If this happens, it may mean that not enough blood gets to your baby’s vital organs. Blurred vision can also sometimes be a sign of pre-eclampsia, so always mention it to your doctor or midwife.
10. Fainting
Whether you’re in the middle of a pregnancy exercise class or not, fainting may mean you have a problem, and it needs to be checked. It could mean something as simple as dehydration, low blood sugar, or low blood pressure, or you could be too warm or exhausted.
However, you and your baby may not be getting enough oxygen, so always tell your midwife or doctor.
11. Pain in your abdomen
Your ligaments may just be stretching, but you could also be having contractions. If the pains continue, you may need your midwife to check you with a monitor to find out whether or not you’re in labour.
In the last trimester, Braxton Hicks contractions can be brought on by exercise. These should settle once you have sat down or rested, though. Contractions or pain that doesn’t go away should be checked out immediately.
12. Vaginal bleeding
Some women have light spotting throughout their pregnancy, but actual bleeding is more worrying. You’ll need to get urgent help if this happens, because early in your pregnancy, it could be a sign of miscarriage. In the second and third trimesters, bleeding could be a sign of:
- Premature labour
- Placenta praevia
- Placental abruption
13. Your baby’s movements slow down or stop
If you notice that your baby does not appear to be moving, or is moving less than usual, tell your doctor or midwife straight away.
Though it's normal for your baby's movements to appear a little less noticeable when you're exercising or rushing around, his movements should return to normal soon afterwards.