Risks of exercise in pregnancy

The risks of exercise in pregnancy

Whilst exercise is considered a benefit to both the pregnant woman and the fetus, there are instances where excessive exercise comes with certain risks.

We do know that hyperthermia and in particular raising your core body temperature to 39C or greater in the first trimester may be associated with an increased risk of fetal anomalies in particular neural tube defects. To raise your core body temperature to this level would take extreme physical activity.

We also know that excessive exercise during pregnancy can be associated with a reduction in utero placental blood flow or blood flow through the placenta. In a normal healthy pregnancy this is not a problem as the body adapts and it has been shown that there is actually no harm to the expectant mother or fetus with a normal level of exercise. This however may not be the case with extreme activity. Similarly, light to moderate physical activity has not been shown to be associated with a reduction in fetal weight or an increased risk of miscarriage.

There are a number of sensible exclusions to exercise in pregnancy and these are well laid out in the guidelines presented by the American College of Obstetricians and Gynaecologists. The College lists absolute contraindications for exercise where exercise should not be undertaken under any circumstance. It also lists relative contraindications to physical activity where you should discuss the possibility of a modified exercise program with your obstetrician or midwife.

If you are unsure of what you should or should not be doing with relation to exercise during your pregnancy, discuss this at your next antenatal consultation. Often this means reassessing your current level of aerobic exercise and continuing at a more gentle pace with activities such as Pilates, yoga, swimming or walking.


Absolute contraindications to aerobic exercise during pregnancy

  • Significant heart disease
  • Significant lung disease
  • An incompetent cervix or presence of a cervical suture
  • Multiple pregnancy with a risk of premature labour
  • Persistent second or third trimester bleeding
  • Placenta praevia after 26 weeks gestation
  • Episodes of premature labour
  • Ruptured membranes
  • Pre-eclampsia or pregnancy induced hypertension
  • Severe anaemia

Dr Len Kliman is one of Melbourne’s most experienced and respected Obstetrician and Gynaecologists. With over three decades of experience he has delivered more than 20,000 babies and still counting!

In 2017, Dr Kliman was awarded an Order Of Australia for his services to obstetrics and gynaecology.