that is what the rule of thumb is and by and large that holds true I'm sure.
When I discussed with Dr. Check about the ranges that are given in the lab reports and how first trimester P4 ranges can go as low as 5 he went ballistic on me (not in a mean way) but told me that you can't go by those ranges because those lab ranges are not based on the P4 levels of live birth PGs - they are based on ALL PGs, including those that end in m/c, are ectoptic, pre-term, etc. They are just ranges based on reported values across all pregnancies vs. values representative of ONLY PGs that resulted in full term live births.
Obviously I don't know if that's true or not but I can see now with my own experience what it means when the placenta kicks in fully and how that is reflected in P4 b/w.
Btw, you were so right about the yeast infection not being yeast but leftover Crinone!