From my own personal experience, I had one Rhogam shot during pregnancy and I regret it. I know more now, and if I get pregnant again I will only get the after birth shot AND make sure it's (supposedly) mercury free, as long as there is no trauma during pregnancy that might result in blood mixing.
Remember, the doctors work for YOU not the other way around. Same with the Vitamin K shot, eye goop, Hep B shot for the baby after birth (if they give those in AU), that is for the parent's to decide, not the doctors.
DS 2006 DiaperFreeBaby March 2010, DD 2011