Anti-D

[lordman]

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UW does not teach Anti-D steps well. Correct me if I am wrong please:

1) You give Anti-D at 28 weeks for all Rh- pregnants, but you only give the second shot within 72h of delivery if the baby is Rh+. In other words, if the baby is Rh-, you don't give a delivery shot.

Is this correct? or regardless to baby status, you would give a delivery shot?


2) If you suspect fetomaternal hemorrhage at delivery, you need to know how much fetal blood transferred then give 300 mq/ 15 ml. What about the cases of clear fetomaternal hemorrhage during pregnancy like abruptio placenta and external version...etc, do you give standard dose of 300 or you need to calculate fetal blood too?

 

[suarad32]

This is what I know (from UTD/UW/MTB):

If the dad is known with certainty to be Rh -ve there is no need for antepartum prophylaxis.
If the fetus is known to be Rh -ve from cell free fetal DNA there is again no need for prophylaxis.

If the mother is Rh -ve and the fetus is or may be Rh +ve:
Do a routine 1st prenatal screening with ICT to determine Ab titers.

A. If titer <16 = not sensitized:
Repeat Ab screen again at 28 weeks to detect the rare case of alloimmunisation (or "seroconversion", if you will) that occurred in the interval between 1st prenatal screen and now.
Give 300mcg of Anti-D at 28 weeks
Repeat dose within 72 hrs of abortion/delivery if baby is Rh +ve (I don't think this is necessary if baby is established Rh -ve at delivery, since you wouldn't bother with any prophylaxis if the baby was Rh -ve on antenatal screens)
If significant fetomaternal mixing (ectopic/ECV/molar pregnancy/CVS/Amniocentesis/abdominal trauma/abruption) you have to do a rosette test to screen and a KB test/flow cytometry to determine if additional doses should be give. I doubt they will ask what to do in unclear/insignificant FM hemorrhage - but if they did, I would go with a KB test all the same.

B . If titer >32 = already sensitized:
Determine fetal Rh status by cff DNA/amniocentesis/paternal zygosity.
If fetus Rh -ve : treat like a normal pregnancy
If fetus Rh +ve start doing serial MCA velocity scans at 24 weeks. If velocity >1.5MoM then do a cordocentesis to estimate fetal hematocrit. If Hct <30% or high bilirubin do an intrauterine transfusion.
Deliver at 37-38 weeks at anyway

C. If prev pregnancy had Rh incompatibility then there is no need for a titer. Start the MCVs at 18 weeks though, and manage with MCVs as above.