Hi - This is Lindsay and I work at the March of Dimes.
Progesterone levels in early pregnancy need to rise, but they can vary a lot from one person to another. Here is a link to good information that discusses changing hormone levels during pregnancy: http://www.americanpregnancy.org/pregnancycomplications/earlyfetaldevelopment.htm
For information on progesterone injections or suppositories to prevent premature birth, read our article: http://www.marchofdimes.com/prematurity/21236_19093.asp
It's always a good idea to discuss any questions regarding treatment with your health care provider. Make a list of questions and keep it in front of you when you talk so you won't forget to ask anything. And don't forget that you are perfectly within your rights to seek a second opinion if you feel unsure about the treatment options your provider offers.
I hope this is helpful. Best wishes,
Pregnancy & Newborn Health Education Center