The greatest risk of forming birth defects and miscarriage occur in the fetal stage.

Yes the statement is True.

Explanation:

There are three stages in the pregnancy. These are called the trimesters. The first trimester starts from week one and continues till week 12. Second trimester starts at week 13 and continues till week 26. Third trimester starts at week 27 and continues till the birth of the baby.

The first trimester is the fetal stage. This is the stage where there are greater chances of forming birth defects. This is probably the first three months of the pregnancy. Most of the miscarriages also occur in this stage. When a baby has a defect, the body detects it naturally and the pregnancy gets waste and miscarriage happens. So fetal stage is the one when the chances of forming the defects and miscarriages are greatest.