Nope, none at all.
The pill works by altering the hormone
levels in your body.
Technically it tricks your body into
thinking it is already pregnant. This
then means that you don't ovulate and that
the mucus in the cervix is thickened.
If for some reason you do ovulate the
thick mucus is unfriendly to sperm and
prevents it passing through.
This is why there is a failure rate,
because some women (rarely) ovulate and
have a thinish mucus.
Taking the pill at irregular
times/skipping pils and such can give
fluctuating levels of hormones and so
makes you more likely to ovulate/have thin
mucus.
The majority of the failure rate of birth
control is user error.
So long as you either began your pill on
the first day of your period, or you have
been taking it correctly for at least 7
days and that you continue to take it
correctly, then you are as protected as
can be by the pill alone.
Remember the pill doesn't offer protection
against std/sti's so make sure your
partner is clean before having sex without
a barrier method of protection.
Oh and have fun when he gets here
