You aren't supposed to have sex for a while after giving birth either. My friend started having sex before she was supposed to when she had her daughter and she got an infection.
Wouldn't it hurt to have sex a few days/weeks after childbirth anyway?
I had 'the talk' from the midwife a day after giving birth, about contraceptives, and how it would be wise to use condoms if I really wanted to have sex very soon. Both because of hygiene, and because some women can conceive straight after giving birth.
Both times the midwife said she should officially have given me that talk sooner than a day after giving birth.
Took me more than a few days to be in the mood again, but it seems to be quite common to have sex really soon after childbirth.