2 prior miscar. before having a child. my previous practice prescribed progestin in case that was the issue. i was told it's inefficient to test levels as they vary greatly and relied on my history. my current pract. says otherwise. who to believe?

First, it may not be inadequate progesterone production which caused the miscarriages. Uterine anatomic conditions (bicornuate uterus, uterine septum, etc.), possible infectious causes, should be investigated. The first sign of potential progesterone deficiency is bleeding/spotting, but treatment with a progestin will not be harmful. Quantitative measurement is not reliable.