Kapha Dosha Imbalance
This overproduces rasa dhatu. Now when the rasa is in excess, the period may take a long time to start. With the earth and water as components of kapha, think of kind of a solid fluidic mass like mud or clay… it takes a long time to get that moving. So when kapha dosha is out of balance it may take a long time for the period to start and a long time for the period to end.
Systemically they have excess fluids in the tissues and may experiencing swelling. Water retention is very common in the week before menstruation due to kapha imbalance. The long duration of menses may go upto 7 to 9 days and, then they may have stagnation in the system which could impede conception and implantation. Imagine if there is too much fluid travelling with the egg, it can become more difficult for the sperm to meet the egg.