Prometrium Dosage & Cycle Effects: What You Need to Know

Question
My doctor put me on Prometrium for my low progesterone I am taking the pills on cycle days 17-26, but since the prescription was new I started taking it on cycle day 22 and ended cycle day 26. The doctor told me that if my period did not start 4 days after taking the last pill to test for pregnancy. My question is should I test or should I wait a few more days and does progesterone delay your cycle?

Answer
Dear Kristin,

Progesterone supplements are often used to "kick start" a menstrual cycle by initiating a period if a woman has not had a regular period for some time. It should not delay one. The body should sense the progesterone drop when you are done with the pills as the end of a cycle and a stimulus to have a period.

Because of this typical effect, your doctor probably just wants to make sure that the lack of a period starting after progesterone supplementation is not related to pregnancy. Go ahead and test for pregnancy four days after taking the pills if a period does not start. If negative, you can wait a few more days and re-test. However, do let the doctor know what is going on. Also - make sure when/if you test that you use 1st morning urine to get a concentrated sample for the most accurate results.

I hope this has helped you and answered your question. I wish you well and a Merry Christmas.

Brenda