So call me crazy, but I have this theory….
I believe that morning sickness is due to the baby’s blood type being one that the mother couldn’t receive in a transfusion. I have done my own informal survey and so far my theory has turned out to be correct.
I did not experience morning sickness at all. My blood type is A+ and my husband’s is O-. This means Eliana either has A+, A-, O+, or O- blood. All four of these are blood types that I can receive in a transfusion. I’ve spoken to a few Nurses and Doctors about this theory and they all tell me there’s no way this is the case since the baby isn’t even sharing blood during the first three months. They dismiss my theory as being silly. But think about it for a minute….Our immune systems drop dramatically when we get pregnant. Doctors believe this is so that the body doesn’t fight off the baby during pregnancy. It isn’t until the 11th or 12th week that the placenta starts functioning and sharing blood with the baby. Miraculously this is usually around the time that morning sickness stops. I believe this is due to our body realizing that the baby isn’t a threat and actually belongs there so things settle down.
So help me with this little experiment if you would? You do not need to reveal your blood type to me. Just follow the exercise and tell me whether you had morning sickness and whether it’s possible your child could be your blood donor or not. Some combinations could go either way, so let me know that as well. If you know your child’s blood type, then you’ll know the answer for sure!
This will be fact some day – mark my words! 
1. Go to this site and put in your and your husband’s blood type and click Calculate:
2. Go here and see if the results show that your child can be your donor.
American RedCross Blood Type Info
Have fun!
Copyright secured by Digiprove © 2011 Naomi Davidson
I have had this theory for awhile also. I was never morning sick at all with three pregnancies. Both my husband and myself are 0-. Thus our children can only be 0-. Now that I am a grandma and I see how sick my daughter-in-laws are…I have decided this could be a fact. Our bodies are very sensitive to something foreign and I beleive it sees the blood type as a foreign enity. Thanks for your insight I find this very interesting and I feel it will be a fact some day also. I will need to get more info from my grown children to prove this in my own family.
I was really sick with my son – he is O+ and I am B- so you may well be right!
this is a very interesting theory. I actually had a similar one, which is what caused me to run into yours. Have you ever considered that it may have to do with the blood type of the husband? Because at the time of conception the man is essentially “donating” his sperm (a new and foreign object w/it’s related fluids). I had the thought that if your blood type and that of your husband are completely compatible, or if your hubby is O-, the universal donor, you are less likely to have morning sickness. My hubby is O-, and I am O+. I have not experienced morning sickness with either of my pregnancies. I was always told it was hereditary from your mom. My mom had NONE, but her mother was sick with all 8 of her pregnancies…. Clearly not hereditary. After talking to my mom, she let me know my dad is O-… Universal donor… Just like my husband. Hmmm, you have given me something to think about.
You might be right, Nana. Therefore anyone with a husband with O- blood is a lucky girl!.
The reason I went more for the baby’s blood type (which of course is determined by the father and mother’s blood types) is that I’ve spoken to women with multiple children from the same father and they had morning sickness with some and not the others. It turns out the children they didn’t have morning sickness with had a compatible blood type. I would like to do a wider study on this and see how close to accurate my theory is. 
Thanks for reading!
Fabulous. I have had the same theory, partly because I was so sick with my daughter and felt there MUST be a reason, not that I was simply unlucky to be so sick. I am O+, my husband is A- and my daughter was born with O- blood type. I’ve taken polls from mothers as well who had severe morning sickness, and it seems there could be something to the theory.
Thanks for posting this.
I totally agree with this theory. I have asked several docs who disagree. I am so happy to see that someone has done the research. I was so sick with my daughter, both hubby and daughter are O+ and I am O-. Also, years ago they required blood tests before you got married? It had something to do with having children…
Your theory is completely wrong. I am O+ and my son is O+ and I had TERRIBLE morning sickness. Plus it makes no sense – your immune system is depressed throughout pregnancy yet morning sickness is typically only present first trimester – it completely corresponds to hormone levels. The only theories which make sense relate to hormone levels and diet – countries with little meat and dairy intake tend to have no morning sickness…they are not sure why.
I understand the immune system is suppressed during pregnancy – it’s so we don’t fight off our babies. Another factor that I’ve noticed is common with low or lack of morning sickness is the level of stress that is present during pregnancy. The less stress, the less sickness. Were you stressed or happy while pregnant? Maybe that’s why some countries don’t have it. We have a very high level of stress in this country…
Agree a 100%. Since I became pregnant I’ve had the exact same thought. I’m really sick, I’m A- and my husband is B+.
I am O positive. 25 years ago I was sick as a dog for ALL trimesters. Actually I was vomiting as I was giving birth! I also became totally out of character vegetation, couldn’t have tea, coffee alcohol.
I only realised I was pregnant because overnight my eating habits were forced to change. It felt as if an alien was suddenly in charge of my body!
My son was born seriously jaundiced so we were hospitalised for 10 days till his bilirubin levels normnalised. He is A-
He has just told me (today) that he is to be a father. His partner same blood group as me … (but not him) she …is sick, sick sick….and just past her first trimester…
I too had that thought about Rhesus factors.. and that is how I found your post…
I’ve had almost no nausea and absolutely no toilet hugging. My child could be my blood donor when born. Interestingly, my husband is O-. Looking at the comments above, I wonder if this pregnancy would have been as easy if my husband had a positive rh factor.
i was hoping your theory was correct only because my current pregnancy which i my 3rd, i have none of the nausea and vomiting that i historically experienced. i have B+ blood type, and my first 2 are all O+ yet with the first – a boy, i had 3 months of sickness….and then my 2nd which was a girl i had 8.5 months of daily vomiting…it was rough! The father of my current child has a A+ blood type and i have no nausea or vomiting….go figure.
I have always thought this about my pregnancies. My husband is B+ and I am A-. I had three pregnancies, They were AB+, B+, and A-. I was the sickest with the B+ baby (so sick I had to have IV therapy). I was a little less sick with the AB+ baby, and I wasn’t sick at all with the A- baby. I just can’t help but think it has a connection!
I have this theory as well which caused me to google it…I had 4 children with my first husband, the first 3 I had literally no morning sickness and the last I was sick for 5 months, found out he was the only positive blood type when I got the “extra” rogham shot at my 6 week appointment…I’m remarried and I’m now in my 5th pregnancy with a lot of morning sickness, well see if this is consistent with our theory in about 7 months
Not true in my case.
Araya is O- and I had morning sickness.
Not the case with me. Both my husband and I have blood type A+, but I had morning sickness with my first and also now as I am pregnant with my second. But I could see how it may affect the severity of the morning sickness. Also, according to The American Red Cross website section on blood types, ethnicity can sometimes affect how well a patient accepts a blood donation, so maybe that is another factor? Hard to tell anything there with my husband and I, though, since we are both a mix of mostly white ethnicities with a bit of native American and African American thrown into our geneologies