Thanks for your query.
pills are given for 21 days and after stopping them you get periods between the 3-7 days.
Mala-D packing has been designed in such a way that you take hormonal pills for initial 21 days and then you take daily the iron pill.
So while you are on iron pill you get your menses.
The packing has been made in this format so that you take pills regularly and do not forget as it becomes a habit to take a pill daily.
Ideally you should start the second pack after the completion of the iron pills irrespective of whether you get menses or not.
Hope this answers your query.