Question

what happens to the thickness of the uterine lining when the level of progesterone reaches its highest level?

Answer 1

What happens at that point is that the lining sheds through the vagina otherwise known as the menstrual cycle which occurs if the egg has not been fertilized.

Answer 2

Becomes thick with blood vessels passing through

Step-by-step explanation:

Progesterone levels are the highest in the middle of the luteal phase i.e at the eighth or ninth day of menstural cycle. it is the hormone which is released after ovulation. It is produced by the corpus luteum (an area created by the collapsed follicle) which consists of ovulated egg. At this stage the uterus lining gets thick and also estrogen is at high level. If the conception does not takes place the level of progesterone falls as the corpus luteum starts to break.