"hierophant" wrote in message
om...
"Cathy" wrote in message
...

I am Rh -, my husband and daughter are Rh +. After DD's birth, I
had the Rhogam shot (or the equivalent) about 2 days after the birth. I
was
surprised at this - I thought it would be almost immediate.

The injection is usually timed to be within 72 hours (which is an
arbitrary number), but it can be immediately following birth or up to
one year. (FYI: The Rh(D)- factor is recessive, so when paternity is
certain and his blood type is Rh(D)+, mother will be making Rh(D)+
babies.)

An Rh- mother and Rh+ father can still produce Rh- children, my parents and
I are proof of this. True it is more likely that the baby will be Rh+, but
not definite, if the father has one Rh+ allele and one Rh- one, making him
Rh+, the baby still has a 50% chance of being Rh-, as there is a 50% chance
the father will pass on his Rh- allele. If the father has two Rh+ alleles
however, the baby must be Rh+. Hence why they still tested my son's blood
type before deciding whether I needed Rhogam.