Surah At-Talaq 65:4

وَٱلَّـٰٓـِٔى يَئِسْنَ مِنَ ٱلْمَحِيضِ مِن نِّسَآئِكُمْ إِنِ ٱرْتَبْتُمْ فَعِدَّتُهُنَّ ثَلَـٰثَةُ أَشْهُرٍ وَٱلَّـٰٓـِٔى لَمْ يَحِضْنَ ۚ وَأُو۟لَـٰتُ ٱلْأَحْمَالِ أَجَلُهُنَّ أَن يَضَعْنَ حَمْلَهُنَّ ۚ وَمَن يَتَّقِ ٱللَّهَ يَجْعَل لَّهُۥ مِنْ أَمْرِهِۦ يُسْرًا

And those who no longer expect menstruation among your women - if you doubt, then their period is three months, and [also for] those who have not menstruated. And for those who are pregnant, their term is until they give birth. And whoever fears Allāh - He will make for him of his matter ease.

Translation: Saheeh International

Tafsir

And as for those of your women who read allā’ī or allā’i in both instances no longer expect to menstruate if you have any doubts about their waiting period their prescribed waiting period shall be three months and also for those who have not yet menstruated because of their young age their period shall also be three …

Excerpt from Tafsir al-Jalalayn, commentary on 65:4, via Quran.com. The reader has the full commentary and 9 more tafsirs.