Are there any red flags that should mean I should stop exercising?  YES.

If you develop any of the follow stop exercise immediately and seek urgent medical attention - 

• Excessive shortness of breath before you have even exerted yourself
• Chest pains or palpitations
• Dizziness or feeling faint
• Painful contractions, signs of labour or leaking amniotic fluid
• Vaginal bleeding 
• Excessive tiredness
• Abdominal, pelvic or back pain
• Severe headache
• Muscle weakness
• Calf pain and / or swelling
• Concerns that your baby is moving less
• Pain in the front or back of your pelvic girdle area - lower spine or abdomen down to your thigh