dropdb breaks replication?

I've two PostgreSQL 9.1.6 running on Linux CentOS 5.8 64bit.
They are replicated asynchronously.

Yesterday, I've dropped a database of 20Gb, and then replication has
broken, requiring me to manually synchronize both servers again.

It is expected that dropdb (or, perhaps, createdb) break existing
replication between servers?

Thanks,

Edson