lfrias23,
low progesterone only rarely causes miscarriage.
moreover, a miscarriage at 16 weeks gestation typically is caused by problems other than low progesterone. such a late miscarriage more likely would arise from the baby having abnormal chromosomes, from you mounting an allergic reaction against the baby(e.g. anticardiolipin antibody, antiphosphotidyserine antibody or lupus anticoagulant), from a tendency of your blood to clot too easily (called 'thrombophilia') or from an abnormality in your uterus.
more typically, low progesterone levels result from rather than cause miscarriage.
a natural progesterone, such as prometrium, causes little hard, but make sure other, more established causes of miscarriage have been ruled out.
david
How far along are you? Did he tell you what your hcg levels were? I had a mc back in Sep ending in a d&c and a natural mc Feb 8th. The levels are supposed to double every 72 hours. If the levels aren't doubling as they should be, then that could be an indication that there is a problem.
The levels were 23oo last week thrusday and abput 4300 this monday. Progesterone dropped form 8.2 to 6.8. I am on 200 mg of prometrium and praying.