You have been following an Rh D-negative woman with antibody titers of 1:32 at her intake obstetric visit and a prior history of a mildly affected infant requiring no interventions except performing...

You have been following an Rh D-negative woman with antibody titers of 1:32 at her intake obstetric visit and a prior history of a mildly affected infant requiring no interventions except performing serial amniocenteses for ΔOD450 values. Her prior ΔOD450 values have resided within Liley zone 1 but have slowly been increasing. Today at her 29-week prenatal visit, she is found to have a ΔOD450 value within Liley zone 3. However, ultrasonography shows no signs of fetal hydrops. What is the next step in the management of this patient?

A. Immediate delivery

B. PUBS to determine severity of fetal disease and possible IV transfusion if indicated

C. Confirm presence of fetal lung maturity and deliver as soon as it is achieved

D. Short course of antenatal corticosteroids followed by immediate delivery

E. Continued serial amniocenteses to assess ΔOD450 value trends and PUBS and transfusion as indicated