Im pregnant and taking prometrium (micronized progesterone) 400 mg a day, why am i so tired?

2 reasons: One of the first symptoms of pregnancy is overwhelming fatigue. This often occurs even before nausea. Unfortunately, this is also a side effect of progesterone supplements. We counsel women to take progesterone at bedtime to minimize the side effects, but some women still complain of fatigue during the day. Try to avoid compensating with caffeine. It's ok to take more naps!