Hello Wendy, In last month's class, we were talking about someone getting a DUTCH test or other bloodwork drawn (estrogen/progesterone) and you said that these tests should be drawn on Day 21 of a 28-day cycle. Then you said that if you have a regular shorter cycle, you would draw them two weeks prior to the period due date; and if a predictable longer cycle, then also two weeks before the period is due. Did you mean that these tests should be drawn on Day 14 if the person has a 28-day cycle? And if not, why the one week difference in timing for a 28-day cycle? Thanks so much! Donna

Wendy said: Sorry for the confusion. If you're looking to make sure progesterone is adequate, you want to draw it at the peak of the luteal phase. The luteal phase will generally be about 14 days, and you want to catch the middle of the luteal phase. So, 21 day cycle means luteal phase starts around day 7, so draw "peak luteal phase" on day 14. 28 day cycle, luteal phase starts around day 14, so "peak luteal phase" is day 21. 35 day cycle, luteal phase would start around day 21, so "peak luteal phase" would be day 28. (you end up doing the labs about a week prior to expected bleeding....which in an irregular cycle can be hard to pin point!) Hope that makes it more clear.