I have been using a fertility monitor for a few cycles and it has been giving me "high" readings on the days that I have noticed the most egg-white cervical mucous. Then, the 2 days that the monitor gives me "peak" readings I haven't noticed any CM at all. So, does this sound like I am actually ovulating a day or 2 earlier than the monitor is telling me, based on CM? Or is it more likely that the monitor is correct and the mucous has just tapered off before I actually release my egg? Thank you in advance for your response.

Cervical mucous is most favorable right before ovulation (12 to 24 hours) and quickly changes back to thicker mucous right after ovulation has occurred. Most fertility monitors measure LH or leutenizing hormone which peaks 12 to 24 hours prior to ovulation. If your mucous changes favorably that is a good sign and strongly suggests ovulation is about to occur. The monitor and cervical mucous changes should coincide, but occasionally may seem a day or so off. The best time for intercourse is in the few days prior to ovulation, ie: one should have intercourse starting four days before the anticipated ovulation, and then every other day until 2 days past ovulation to allow for cycle to cycle variation. If one is concerned about whether ovulation occurred, a blood progesterone level sent from your doctor's office one week after ovulation should confirm that ovulation did occur.

Answered by Dr. Lynn Friedman, M.D.