Why would you be concerned about the potential bloodtype of your unborn baby?

If you were having a child with the express purpose of trying to save someone else using bone marrow or cord blood, then I could see the point. However, if that was the case, you’d have genetically selected the correct embryo in the first place.

Just because we were curious, last year, we bought home test kits to determine our daughter’s blood type. It was fun. Since my husband and I already knew ours, we used our blood to test the accuracy of the results.

He he. This reminds me of your romance-book-no-period-pregnant question on Askville. That was a good one!

The only real concern is if there is a potential rh factor problem. And some people use it as a preliminary (not definitive) paternity test.

I’m pretty sure these uniformed users thought that blood type could establish paternity.

When the mother is found to be Rh- and the father has Rh+ blood, the mother needs to receive a treatment to help prevent the development of substances that may harm the unborn baby. This is the most common reason why one needs to know baby’s blood type.
But in Askville it is mainly related to Paternity. Such questions were mostly asked by teenagers and they know DNA testing is expensive, so most of them choose to first compare the baby’s blood type to mom’s and dad’s. Even though the blood test results cannot pinpoint who the exact father is, still they can tell who isn’t the biological “dad.”

Over here we get “Could I be pregnant” questions all the time. The answer almost invariably is “possibly.”

@flip86 “Uniformed” or “uninformed”?

If I understand the question it is asking what blood type the baby likely will have. All I can think of is if someone needs an organ, blood or tissue match for donation or transplant. But, people who need it for that purpose I can’t imagine would be asking on askvillem because something pretty serious medically would be going on and a doctor or geneticist would be consulting with them about the chances a new baby would be a match.

If the person is wondering if there were adopted themselves.

Someone mentioned Rh factor, which is a concern if the mother is Rh negative, but usually not a concern with a first pregnancy. This sort of thing would be discussed with a doctor also, so I doubt the questions are about Rh factor.

There are some people who believe your blood type determines some other traits and they believe in eating a diet associated with their blood type.

If they are asking about paternity I don’t see why they would not ask it with wanting to rule a possibilty out. Like if one or both parent is AB you can’t have an O baby. Two A parents can have an A or O baby, but impossible to have a B or AB baby. The basics rule possibilites out more than it can give a conclusive answer what the baby’s blood type will be.

There are a lot of myths about the “importance” of blood type with respect to diet and common diseases. As I recall, we have at least one jelly who talks about this a fair bit.

However, if you’re interested in scientific evidence, the only times blood type matters is in rh factor compatibility (as @zenvelo mentioned).

Huh. I was going to write a bit about diseases like sickle cell anemia, but it turns out that’s not linked to blood type, either.

I have the RH negative factor and my ex was positive, I had to have the Rhogam shot to be sure my daughter would not reject the mixed blood types. This used to be a serious condition, often leading to infant death.

Yep I was the second child of a o- mother and b+ father.
She had to have the rhogam shot.

@zenvelo Damn typos. I meant “uninformed”.

I was wondering what kind of uniforms…

Sometimes blood types turn out to be rare, even extremely rare.

For example the rarest blood type known appears to be unique.

Obviously this could be a problem at some point.

So, the consensus at this point is that the questions were just as pointless as I feared? I can’t believe that the rhogam shot is that prevalent. I suspect that, as @flip86 said, the youngsters were trying to narrow paternity options.

Thanks all. Thanks to @Smitha, @Coloma and @Unbroken for making me aware of a condition I had previously been unaware of.

They are afraid that the person they hope is the father really is the father and don’t want big questions to arise if the blood type ends up being neither the mothers or the “fathers.”

Highly likely, @Judi.
Thanks.

Even I had to take the RhoGam shot. I am Rh negative and husband is positive.

Everybody Type O Positive say haaaaay!

Do they give RhoGram even on first pregnancies? I had thought they don’t worry about the first one.

I think about 15% of the US population is Rh negative, so that makes for a lot of couples who have a negative mom and a positive dad. Certain ethnic groups have much higher incidence of Rh negative.

@JLeslie, they do because someone could have miscarried and not realized it thinking they just had a heavy period. My daughter is RH negative. She has done some research. Some scientists think it may be Neanderthal. They think that interbreeding might be why they died off. The RH negative people are their defendants.
Here’s a link to some info

@Judi I thought it was delivery that triggered the problems, not the pregnancy itself. That bleeding during delivery allowed the blood to comingle or something. Then after that the mom’s body had an effect on future pregnancies. I hadn’t even thought of miscarriage. It makes sense. I’ll google it.

I knew some of that information from your link, namely the Basque information regarding the Rh factor. The French and Spanish I think still have some of the highest oercentages of Rh-, other European caucasians behind them from what I remember. It’s really really rare among Asians and Africans.

No. The mother develops antibodies to the positive blood and rejects future pregnancies.

@judi Yeah I know, but I thought it was because of tears during delivery or the process of delivery. Then future pregnancies the mother’s body recognizes the factor and has an immune reaction. I never really read up on it. I’m going by what I heard, which could easily be completely wrong. I’ll look it up. Your miscarriage scenerio makes sense it would affect it too though. Thanks for the info.

@JLeslie Rh-positive blood cells may cross through the placenta into the mother’s body. This may happen during pregnancy as a result of the baby’s circulation system.

@Juels That makes sense actually, because as I think about it Rh would not matter at all if the mother’s body didn’t somehow detect the Rh+ factor from the developing fetus. I have a feeling what I heard was an old wives tale. Maybe since our immune systems get better at fighting (even if it kills us) foreign invaders each time we are exposed, miscarriage rates maybe went up with each pregnancy and people interpeted as first baby’s are safe. That’s my guess anyway.