What are some of the most likely reasons a woman's estrogen might be high?

--Ronda

Pregnancy is the most common reason for a high level of estradiol (the predominant type of estrogen circulating in the body). Estradiol levels vary quite a bit throughout the menstrual cycle, too. During menstruation estradiol levels are around 45 pg/ml. By the time of ovulation, levels rise to around 400 pg/ml, then fall rapidly, then rise slowly to about 250 pg/ml before dropping again. During pregnancy, estradiol levels are about 100 times higher!

Another reason for an elevated estradiol level is estrogen replacement. After menopause, in women not on hormones, estradiol levels are 10-20 pg/ml. We know that the level of estradiol needed to maintain healthy bones in menopause is only 40-50 pg/ml. Some women, however, need higher levels than this to avoid hot flashes. However, levels higher than 200-400 pg/ml (the levels an ovulating woman achieves) are probably too high in postmenopausal women. Very high levels can be achieved with higher doses of hormone replacement, but such very high levels increase risks of abnormal clotting of the blood.

In order to interpret your estradiol levels, you should talk to your doctor; the levels must be examined in the context of where you are in your reproductive life.