Honestly i was scared to even smell pineapple in my last month, but my gynac laughed and said one normal serving wont do anything. Still, since u r so close to delivery, maybe just confirm with ur doctor for peace of mind.
The thing people worry about is bromelain in the core, but u get very little of it from normal fruit. My doctor said moderate amount is safe even late in pregnancy. If u have any risk factors though, ask her directly.
Since u r in the final month, i would just check with ur gynac once before adding anything new. In my case they wanted me to be a bit careful, so better safe na.
A few pieces are fine, the whole myth of pineapple starting labour is from eating huge amounts. I ate it in my 9th month, nothing happened. Just dont go overboard.