Negative Blood Types and Pregnancy…


What’s the deal?


If you’ve found yourself reading this, it’s very possible you just found out that being a part of the tiny percentage of people that have a negative blood type, could affect your pregnancy. This can be very daunting to hear. What’s even more frustrating is hopping on google and finding very little information about negative blood types regarding pregnancy and seeing ridiculous articles about being part alien or the missing link. So now I’m a pregnant alien? Yeah, okay.

 What is a negative blood type?

According to “Blood is typed according to something called the Rh factor. This is an antigen found on red blood cells. If the cells have the antigen, they’re considered Rh-positive. If they don’t have it, they’re considered Rh-negative. Depending on whether the Rh antigen is present, each blood type is assigned a positive or negative symbol.”

Fast forward to the day after my daughter was born; we are in the hospital and the pediatrician walks into our room to introduce herself and says “Hi there, I’m Dr. so and so.  I’m going to do a routine examination, and by the way your daughter is a O positive blood type” and she continues to keep talking. My husband and I stop her and say, “um, I think you have the wrong file. I’m A negative and he’s A positive.” She gives us a super awkward puzzled look and says, “I’ll be right back.” Five minutes pass, she comes back into our hospital room and says “Good news! Your wife did not cheat on you! Two As can make an O! Wow it’s been a while since medical school.”

We laughed and found it interesting buy my gosh, no kidding I didn’t cheat on my husband, she looks just like him! I only baked her BY MYSELF WHILE MY HUSBAND WAS IN IRAQ FOR MY ENTIRE PREGNANCY. My husband deployed when I was only 13 weeks along and thank God my morning sickness went away shortly after. Having held down the home fort while working 32 hours a week as a zookeeper, and living with a pregnancy induced hernia, I worked pretty dang hard to bake this baby!

So why does having a negative blood type matter when you’re pregnant anyways? Well, odds are your child has a positive blood type. Unless your partner also has a negative blood type.

“When it comes to the Rh factor, people with Rh-positive blood can receive either Rh-positive or Rh-negative blood, while people with Rh-negative blood can only receive Rh-negative blood. In some cases, a woman with Rh-negative blood can carry a child with Rh-positive blood, resulting in a dangerous condition called Rh incompatibility.”

Do not let this scare you. Modern medicine has got your back- it’s called the RhoGam shot. Let me translate- during pregnancy, baby and mom have a separate blood supply. Occasionally during pregnancy, blood can pass through the placenta into moms’ body, but this can also occur in an ectopic pregnancy, during an amnio, during early pregnancy bleeding, or blood can mix during delivery. If moms immune system detects the foreign protein in her body, the body begins producing antibodies to protect itself and attack.  Let’s say you make it all the way through pregnancy with no issues then during delivery your baby’s blood and your blood mix, your body now is producing antibodies so the next time you get pregnant, if the body detects your growing child is positive, your antibodies will prevent that baby from growing. Moms with negative blood types are able to manage this by receiving the RhoGam shot at around 28 weeks pregnant, and sometimes you’re given another dose after delivery, to prevent your body from producing antibodies.


 Negative blood types are rare, I encourage you to consider donating blood if you have a negative blood type. Less than 10% of the population donates blood, yet someone is in need, every 2 seconds. Find a donation bank by clicking here if you’re in the US and here if you’re in Australia. Below you can find a breakdown of compatible blood types.



Compatible Blood Types

O- can receive O-

O+ can receive O+, O-

A- can receive A-, O-

A+ can receive A+, A-, O+, O-

B- can receive B-, O-

B+ can receive B+, B-, O+, O-

AB- can receive AB-, B-, A-, O-

AB+ can receive AB+, AB-, B+, B-, A+,  A-,  O+,  O-