What are the chances of your baby being rh negative like you?

If you are an rh negative woman, what are the chances that your child will also be rh negative?

One of the main reasons for starting Blood Type Dating is that rh negative women rightfully worry about whether or not their pregnancy will go well. Having an rh positive fetus can cause issues due to rh incompatibility. You can read up more on it here.

The question I get a lot is what the chances are for an rh negative woman to also have an rh negative child. In that case, the worries are laid to rest.

Here are the possible outcomes in pregnancies in terms of rh factor in the fetus:

If the father of the child is...

Rh Negative

In that case, the child will be rh negative. If both of you are rh negative, there is no other possible outcome than the fetus being rh negative like you and with that no chance of the rh disease kicking in.

Rh Positive

This depends on the genotype of the father. Is he homozygote (+/+) or heterozygote (+/-)?

If he is homozygote (+/+):

There is no other outcome than the baby being rh positive, but the baby will be a heterozygote, meaning he or she carries your rh negative blood factor gene recessively and is able to pass it on later in life to his or her kids.

All children will wind up being +/-, meaning their phenotype is rh positive and their genotype a mix of rh positive and rh negative blood. Since rh factor positive is dominant, your babies will be rh positive.

If he is heterozygote (+/-):

Mathematically speaking, there is a 50/50 chance of your child being either rh positive or rh negative. If rh positive, he or she will carry the rh negative blood factor recessively and will be able to pass it on to future generations.