I cant comment specifically on obstetric cover over the holidays, I worked on a general surgical ward until recently. i do agree that it used to be the case where in general, places were "ran short" over the holiday period, but please let me try to reassure that that just does not happen anymore. i know this from doing the rota the last few years!! gone are the days when people dont want to be in hospital over christmas, and we even had several patients going to theatre for relatively minor surgery last christmas day.
have you chatted this over with your consultant? he/she should hopefully be able to clarify if the labour wards and postnatal wards are staffed as normal. In a and e when i worked there (and that was several years ago now), we never ever ran below normal numbers of staff, and all other high care area's are the same. hope that helps a little xx