All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
There are authentic Hadeeths (narrations) concerning the merits of Madeenah. The Prophet, sallallaahu ‘alayhi wa sallam, used to supplicate Allaah The Almighty to bless the measures of the people of Madeenah. An-Nawawi said that the word ‘blessing’ in this context means to make an amount that is considered little everywhere else sufficient in Madeenah.
One of the female Companions said that the Prophet, sallallaahu ‘alayhi wa sallam, expressed a desire to die in Madeenah if this was possible, , saying that it testifies and intercedes for the one who dies in it. [At-Tabaraani. (Hasan)]
Moreover, the Prophet, sallallaahu ‘alayhi wa sallam, recommended anyone to live there. [Muslim]
In principle, a Muslim has to worship Allaah The Almighty according to the Sharee’ah. Burying the placenta in Madeenah was not recommended in the Quran, or the Sunnah and it was not established by the consensus of the scholars. Apparently, it is a Bid‘ah (an innovation in religion), hence prohibited.
Allaah Knows best.