In at risk pregnancies with nonsignificant titers or MCA-PSV values consistently below 1.5MoMs, mild to no anemia can be presumed with a scheduled delivery at 37 to 38 weeks gestation 3.
There is an increased risk of false positive (elevated) MCA-PSV values beyond 35 weeks of gestation10. It is generally agreed that a high value at or beyond 35 weeks of gestation merits delivery. In a pregnancy requiring IUTs, the final procedure is usually planned at approximately 35 weeks with delivery planned at 37-38 weeks gestation.
Follow additional protocols regarding steroid administration and other preventative treatments in advance of preterm delivery. Be aware that steroid administration has been shown to falsely lower fetal blood velocity 8, 9, 35, 36 and expert opinion holds that steroid administration has been shown to falsely lower MoM values. Planned delivery should not be modified based on MoM values observed after administration of steroids.
As part of a delivery plan, the MFM should connect the patient with services such as a NICU tour, a consultation with a pediatric hematologist, and a neonatologist after birth. Infants with HDFN should not be discharged from the hospital until a hematology appointment has been made. This will ensure proper follow up care for neonates exposed to maternal alloantibodies.
