From Sahih Muslim (Hadith 3547):
Abu Sa'id al-Khudri (Allah be pleased with him) (was asked if he had heard it himself), to which he said:Yes. (I heard) Allah's Apostle (ﷺ) as saying: There is no harm if you do not practise it, for it (the birth of the child) is something ordained (by Allah)
Reference: Muslim 3547