If you're trying to get pregnant, you might think a lot of progesterone is just what you need. But too much of it can be just as detrimental to your pregnancy chances as too little because it can actually act as a contraceptive [source: Kittel].
And it's not just long-term high progesterone that's problematic. A one-time boost of progesterone into a body with normal levels can upset the process of conception by pushing the endometrium into sloughing and, thus, causing menstruation to begin [source: Jelovsek].
Other effects of high progesterone include tiredness, vaginal dryness, high insulin levels, decreased insulin sensitivity, weight gain, reduced sex drive and depression.
As you can see, tinkering with hormone levels is complicated and only advisable when a legitimate imbalance is present. To ensure you aren't exacerbating your infertility, see a specialist for guidelines on regulating progesterone levels -- if it's even needed at all.
To read about other fertility issues, check out the next page for lots more information.