My Wife Have Regular Periods. We Are Just Married And

my wife have regular periods. we are just married and trying for pregnancy. this month her period was delayed for a week and pregnancy urine test was negative and started menses on 23 rd still menses continued till date. now our doctor prescribed regestrone 5 mg three times daily for 21 days.
my question is it safe to have regestrone for this much period, due to its side effects or we can wait for few more days by taking hemostatics(tranexamic acid) until period ceases and begins in it own.