In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
Cosmetic surgery is only permissible if one has a natural defect and he or she wishes to correct that defect. For example, in the case where one was born with extra fingers or extra toes then, it will be permissible for the person to undergo surgery to remove the extra fingers or toes.
On the other hand, if there is no natural defect and the person merely desires to undergo cosmetic surgery solely to enhance his or her beauty then such a procedure will be impermissible in Shari’ah.[i]
Please note also the following Ayat of the Quran Majeed:
وَلَأُضِلَّنَّهُمۡ وَلَأُمَنِّيَنَّهُمۡ وَلَأٓمُرَنَّهُمۡ فَلَيُبَتِّكُنَّ ءَاذَانَ ٱلۡأَنۡعَٰمِ وَلَأٓمُرَنَّهُمۡ فَلَيُغَيِّرُنَّ خَلۡقَ ٱللَّهِۚ وَمَن يَتَّخِذِ ٱلشَّيۡطَٰنَ وَلِيّا مِّن دُونِ ٱللَّهِ فَقَدۡ خَسِرَ خُسۡرَانا مُّبِينا [النساء: 119]
And I lead them astray and I will tempt them with false hopes and give them my order
So they shall slit the ears of cattle
And I give them my order so they shall alter the creation of Allah.
And whoever takes the Shaitan as a friend instead of Allah has incurred an obvious loss. (Surah Al-Nisaa 4:119)
You should also take note that there is no guarantee that your future husband will be dissatisfied with your breast as they are at present. It may be that you undergo this procedure to your own detriment.
We advise you to make Shukr and to be pleased with the decree of Allah Tabaraka wa Ta’ala.
And Allah Ta’āla Knows Best,
Mufti Saeed Ahmed Golaub.Islamicsolutions.org
«الكوكب الوهاج شرح صحيح مسلم بن الحجاج» (21/ 505): [i]
«وأما قطع الإصبع الزائدة ونحوها فإنه ليس تغييرًا لخلق الله وإنه من قبيل إزالة عيب أو مرض فأجازه أكثر العلماء خلافًا لبعضهم كالطبري»