﴿ وَٱلَّٰٓـِٔى يَئِسْنَ مِنَ ٱلْمَحِيضِ مِن نِّسَآئِكُمْ إِنِ ٱرْتَبْتُمْ فَعِدَّتُهُنَّ ثَلَٰثَةُ أَشْهُرٍۢ وَٱلَّٰٓـِٔى لَمْ يَحِضْنَ ۚ وَأُو۟لَٰتُ ٱلْأَحْمَالِ أَجَلُهُنَّ أَن يَضَعْنَ حَمْلَهُنَّ ۚ وَمَن يَتَّقِ ٱللَّهَ يَجْعَل لَّهُۥ مِنْ أَمْرِهِۦ يُسْرًۭا ﴾

“Now as for such of your women as are beyond, the age of monthly courses, as well as for such as do not have any courses, their waiting-period - if you have any doubt [about it] - shall be three [calendar] months; and as for those who are with child, the end of their waiting-term shall come when they deliver their burden. And for everyone who is conscious of God, He makes it easy to obey His commandment:”

Please check ayah 65:5 for complete tafsir.