Still not quite sure what the OP is asking. Is it

A: Placentas from foreign women giving birth in the UK must be taken out of the UK to prevent disease? (Answer: Not true)

or

B: If you want to take a placenta out of the UK it must be sent by courier, not hand-luggage? (Answer: That probably depends on your airline)

In any case, there is nothing to stop you giving birth in the UK! Good luck with your pregnancy and your studies.