At 28 weeks gestation, amniocentesis reveals a AOD 450 of 0.20 which is at the top of third zone of the liley curve. The most appropriate management of such a case is:

Management of Rh negative females depends on whether the female is immunized/ nonimmunized. The question which says- what should be done in case of the paitent with 28 weeks pregnancy if ∆ OD lies at the top of Zone 3.