  We investigate p-wave pion production in nucleon-nucleon collisions up to
next-to-next-to-leading order in chiral effective field theory. In particular,
we show that it is possible to describe simultaneously the p-wave amplitudes in
the $pn\to pp\pi^-$, $pp\to pn\pi^+$, $pp\to d\pi^+$ channels by adjusting a
single low-energy constant accompanying the short-range operator which is
available at this order. This study provides a non-trivial test of the
applicability of chiral effective field theory to reactions of the type $NN\to
NN\pi$.
