Hi and welcome to HCM.
What about amylase
It is not common that such lipase level elevation is related to menstruation
or any other organ but pancreas
or bowels. You should focu on these to and rule out any serious disease. In pancreattis lipase level varies during the day and this is nothing strange. Some abdominal partial or temporary bowel obstruction or gallbladder
problems can cause lipase level elevation as well. I would do further tests,imaging and lab to find is there any particular cause of it.
Wish you good health.