The signs of a miscarriage differ according to the length of pregnancy but there are some good indicators to be aware of:
This is the main warning sign of a miscarriage. Bleeding may vary, it might start, then stop, before starting again. If you're bleeding constantly, you should go to hospital as quickly as possible. After you experience bleeding, you should have a thorough examination and lie down as much as possible.
Pain and bleeding
Pain isn't really a sign of miscarriage in itself. However, if pelvic pain is accompanied by cramps, diarrhoea, vomiting or period-like pain, it could be the start of a miscarriage.
If the pain isn't accompanied by bleeding, it's not worth going to hospital: the doctors can't do anything to stop a miscarriage.
The only emergency available is when bleeding is constant and abundant: you'll most likely have to have a D & C procedure (Dilation and curettage).
Disappearance of pregnancy symptoms
If the signs of pregnancy (swollen breasts, etc) disappear, it could also indicate a miscarriage.
It's often during the ultrasound scan that the end of a pregnancy can be detected. A 'dead egg' can stay in place for 4 to 10 weeks.