As salamu aleykum,
It happens on a regular basis that i am doubting that I have forgot one of the two sajdah’s when praying. What should I do in this case? Will sajdah sahw suffice to remove my doubt?
In the name of Allah, Most Compassionate, Most Merciful.
Sajdah in salah is fardh and therefore it needs to be performed. However if there is doubt that has one sajdah has been performed or two then a person should act on what is the most likelihood. If it is most that he has only performed one then he should perform another sajdah and do sajdah sahw for delaying a compulsory act. (Fatawa Alamghir, Vol 2, P126)
And Allah knows best
Darul Ifta Birmingham