At Talaq, 4 Ayah
65:4
وَٱلَّٰٓـِٔي يَئِسۡنَ مِنَ ٱلۡمَحِيضِ مِن نِّسَآئِكُمۡ إِنِ ٱرۡتَبۡتُمۡ فَعِدَّتُهُنَّ ثَلَٰثَةُ أَشۡهُرٖ وَٱلَّٰٓـِٔي لَمۡ يَحِضۡنَۚ وَأُوْلَٰتُ ٱلۡأَحۡمَالِ أَجَلُهُنَّ أَن يَضَعۡنَ حَمۡلَهُنَّۚ وَمَن يَتَّقِ ٱللَّهَ يَجۡعَل لَّهُۥ مِنۡ أَمۡرِهِۦ يُسۡرٗا ٤
Wa Al-Lā'ī Ya'isna Mina Al-Maĥīđi Min Nisā'ikum 'Ini Artabtum Fa`iddatuhunna Thalāthatu 'Ash/hurin Wa Al-Lā'ī Lam ۚ Yaĥiđna Wa 'Ūlātu Al-'Aĥmāli 'Ajaluhunna 'An Yađa`na ۚ Ĥamlahunna Wa Man Yattaqi Al-Laha Yaj`al Lahu Min 'Amrihi Yusrāan
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 Allah - He will make for him of his matter ease.