You doctor is lying! Find another doctor RIGHT NOW! I had two children pass away before discovering I had progesterone problems. We had given up having any more children. We were surprised with another pregnancy.....I got a new OB. He tested all hormone levels and discovered my progesterone was low. From then on I tested ever week until the baby was full term. I had to supplement with shots of natural progesterone for nearly the entire pregnancy. PM me if you have any questions. Find a doctor that is affiliated with the Pope Paul the VI Institute. They train doctors from all over the world.
Edit:
I didn't have enough time to post everything I wanted to say.
Yes, progesterone tests can very. You need to go with someone that knows what they are doing. An endocrinologist may be able to help if you can't hook up with someone from the PPVI Institute. I live quite a distance from the doctors there so I had my blood drawn at my local hospital and sent to the national lab at the Institute. They then would give me a call to adjust my dosage of progesterone. It is best if natural progesterone is used. The doctor that founded the Institute is known all around the world for cutting edge research in fertility care.
My local OB did not believe in following progesterone past the first trimester if at all. He kind of made light of the progesterone. At one point during the my pregnancy the local hospital accidentally ran the blood work in their own lab. The test can vary depending on how it is run. By the time everything was squared away my progesterone had fallen and I began having serious cramping. They were able to catch it in time and once my levels were adjusted all was well again. By the end of the pregnancy I could feel when the levels were falling and could predict when the blood work was going to show a drop.
Many doctors these days think that if your progesterone is low that there is an issue with the baby and the pregnancy wasn't meant to be, so to speak. That is not the case. Many also believe that the placenta will produce enough progesterone in the second trimester so testing at that time is useless. That also is not the case. I had babies that died in the first trimester as well as in the third.
Find a doctor that is more up to date on the latest information on progesterone. I did and my youngest child wouldn't be here had I not.