Understanding Miscarriage & Low Progesterone: What to Ask Your Doctor

Question
Hi

I have 2 healthy children a 2 year old and a 7 month old, after the birth of my last child and just before getting pregnant (LMP 17 August 05) my luteal phase ranged from 7-8 days.

Unfortunately I recently lost this baby at 12 weeks (10th november 05) it was my first M/C, the baby measured 10w6d.

I am wondering if i lost this baby due to a progesterone deficiency. I know you cant comment or diagnose that but my question is would it be feasable to ask my doctor to test my progesterone levels or would the placenta have already taken over making progesterone redundent.  Until what stage of a pregnancy is progesterone important?

I hope you can help me
thank you

Answer
It is certainly possible that you have a low progesterone level. This may or may not have been the reason for the miscarriage, but is probably the reason that you have a short luteal phase. It couldn't hurt to have a progesterone level done. Usually, by 12 weeks, the placenta produces enough progesterone, but you lost the baby at 10 weeks. Now there is nothing you can do to prevent a miscarriage and there is nothing you can do to cause a miscarriage. However, if you start progesterone supplementation, it may help.