Hows does a inevitable miscarriage happen ?

Cervix dilation: An inevitable miscarriage describes the condition when a pregnant woman's cervix is dilated early in pregnancy. This indicates that she is about to have a miscarriage. The most common reason for any miscarriage is an abnormality in the chromosomes of the fetus.

Miscarriage: We don't always know but a lot of the times it is from a miss match of the genes. This causes a lethal problem in the baby and the body then tries to rid itself of the abnormal pregnancy. Hope this helps.