What is the main difference between amphibians and arthropods?

I do think that the main difference between amphibians and arthropods is that amphibians are vertebrates while arthropods are invertebrates

The right answer is : it may be miscarriage

In case of abundant bleeding, accompanied by clots and menstrual pain, it is possible that it is a miscarriage (a medical consultation is required). It is a situation that affects a beginning pregnancy on 5 or 6, with a risk twice as much as 40 years than 20. In nine cases out of ten, these early miscarriages are due to a chromosomal abnormality of the embryo. It can also be a clear egg, with an empty uterine sac.

For the more advanced pregnancies, this accident can be due to various causes: a shock or a fall, a detachment placentaire, an infection or a disease. Expulsion of the embryo or fetus, if not done alone, will require medical intervention.