Miscarriage Chances

I found this on the i-net today about miscarriage at 9 weeks:

The highest risk period is between 4 and 6 weeks. Once 8 or 9 weeks are reached and the baby's heart beat is seen on a scan there is only a 4% to 5% chance of miscarriage, depending on the speed of the heart-beat. It should be 120 to 160 times per minute. (BMP) The risk then drops to between 5% and 8% and continues to drop as the pregnancy proceeds. (came from a UK study)

The risk of miscarriage decreases sharply after the 10th week, i.e. when the fetal stage begins. The loss rate between 8.5 weeks and birth is about two percent; loss is “virtually complete by the end of the embryonic period. " (From Wikipedia)

The statistics regarding miscarriage vary widely depending on the source. Here are some of the basic numbers. (from a message board)

Almost 20% of pregnancies end in miscarriage, with the majority occurring during the first 12 weeks.

There is a 75% chance of miscarriage in weeks 1-2 of pregnancy, when you do not know you are pregnant.

There is a 10% chance of miscarriage in weeks 3-6 and this number drops to 5% during weeks 6-12.

During the second trimester the chance of miscarriage drops again to 3%. After you’ve reached 20 weeks gestation, it is no longer considered a miscarriage