Survey study, 1987
Does taking progesterone by suppository increase progesterone in the blood?
Yes, but less so over time. On the first day, progesterone levels rose clearly after taking the suppository. By day 8 of treatment, the rise was smaller.
What they did
Researchers gave 4 women 400 mg progesterone vaginal suppositories during the second half of their menstrual cycle. They took blood samples before insertion and at five time points up to 8 hours after insertion on days 1 and 8 of treatment.
What they found
On day 1, progesterone levels rose substantially from baseline. On day 8, the rise was smaller. There was a clear negative relationship between how much progesterone rose and how many days the women had been using suppositories.
What it means for you
The body may become less responsive to the same dose of progesterone over time, but the exact reason is unclear. This was a very small study of only 4 women, so findings should be interpreted cautiously.
4
women
400 mg
progesterone dose
8 hours
blood sampling window
About the study
- Original title
- Serum progesterone levels following vaginal administration of progesterone during the luteal phase
- Authors
- Myers ER, Sondheimer SJ, Freeman EW et al.
- Journal
- Fertility and sterility
- Year
- 1987
- Study design
- Survey study
- Participants
- 4
- Open access
- Yes
- Read the paper
- doi.org/10.1016/s0015-0282(16)49938-3