a girl of mine went into what i thought to be labour,she started to push and brown smelly stuff came out,she had pyrometris which is an infection in the womb,she had to have a emergency hysterectomy.keep a close eye im sure she will be fine,when she starts to push it can take up to a hour for babe to come out,dont let her push for longer than that,contact vet for advice.the same goes for any subsiquent kitts.good luck and dont panic