What is the source for not buying baby clothes before birth?
And practicaly speaking, how is one to deal with this is places where one is discharged from hospital hours after birth (espacially – but not only – with the current situation)?
I am not aware of any halacha that prohibits this, and it seems to be a sort of hanhaga or minhag that people do. My assumption is because of the idea of “ain habracha metzuya elo bdavar hasomuy min hoayin”, and ayin hora. Being that it is only an inyan, and not a halacha, if it is difficult for you otherwise you can be lenient with it.
Shulchan Aruch Hamikutzar 4:page 319:19:footnote 58, V’ein Lumo Michshal 2:page 322, Bais Hayehudi 10:page 170. I have also seen this in the name of this is the opinion of Harav Yisoel Belsky zt”l and YBCHLCH Harav Shmuel Felder Shlita.