Sura al-Ṭalāq 65:4

وَٱلَّٰٓـِٔى يَئِسْنَ مِنَ ٱلْمَحِيضِ مِن نِّسَآئِكُمْ إِنِ ٱرْتَبْتُمْ فَعِدَّتُهُنَّ ثَلَٰثَةُ أَشْهُرٍ وَٱلَّٰٓـِٔى لَمْ يَحِضْنَ وَأُو۟لَٰتُ ٱلْأَحْمَالِ أَجَلُهُنَّ أَن يَضَعْنَ حَمْلَهُنَّ وَمَن يَتَّقِ ٱللَّـهَ يَجْعَل لَّهُۥ مِنْ أَمْرِهِۦ يُسْرًا

wa-allāʾī yaʾisna mina l-maḥīḍi min nasāʾikum ini irtabtum fa-ʿiddatuhunna thalāthatu ashhurin wa-allāʾī lam yaḥiḍna wa-ūlātu l-aḥmāli ajaluhunna an yaḍaʿna ḥamlahunna wa-man yattaqi allāha yajʿal lahu min amrihi yusran

Such of your women as have passed the age of monthly courses, for them the prescribed period, if ye have any doubts, is three months, and for those who have no courses (it is the same): for those who carry (life within their wombs), their period is until they deliver their burdens: and for those who fear Allah, He will make their path easy.