If an on-call obstetrician attends a delivery on behalf of the primary obstetrician (perhaps because they are unavailable at that time), should the on-call obstetrician bill with Medicare and then pass this income on (less an agreed service/locum fee) to the primary obstetrician or should this be the other way round? Existing item numbers only seem to cover services that extend beyond the delivery (i.e. delivery plus at least 5 days of post natal care, etc). I am asking in the context of the on-call obstetrician only being involved in the delivery and not any of the pre-natal or post-natal care. I need to establish billing practices for this exact scenario.