Kerry is RH negative. This means if her baby is RH positive, she could develop antibodies against her babies blood which means her body could “attack” the babies red blood cells and cause RH disease. It is rare that this would happen with her first child, but there is some danger to future children as she may develop these antibodies in this pregnancy and then go on to reject future fetuses that are RH positive. She has been advised to have an Anti-D immunoglobulin shot at 26 weeks. We decided to look into this and there are a lot of things to think about before just taking this, or any, shot.

- First, some versions of this shot have mercury in it. If Kerry decides to take the shot, she will choose a mercury-free version (BayRho and RhoGAM make one).

- Next, the shot is a human blood product. There are always risks of diseasae associated with this even though it is highly filtered. There are also other side effects such as swelling, inflammation, hives and anaphylactic shock. Furhterore, some studies have indicated that having the injection may affect the immune response of both mother and baby to other foreign substances entering the blood stream.

- Thirdly, after doing some research, the Anti-D immunoglobulin shot is only effective within 72 hours of fetal and maternal blood mixing. Therefore, they recommend you get booster shots throughout your pregnancy. An article on Natural Birth and Baby Care describes it like this:

“The Anti-D shot is only effective within 72 hours of maternal-fetal blood mixing. So even if the injection is given at 28 weeks, it will only help if maternal and fetal blood has mixed 72 hours or less before the injection. The Rhogam manufacturer states that an injection every 12 weeks will maintain a ‘passive immunity,” meaning that theoretically a shot every twelve weeks will protect you in the event of trauma causing your and your baby’s blood to mix. They still recommend a new shot at the time of blood mixing if greater than 15mL of exposure has occurred.”

So, the question is when, if, and how often to take the shot?

We learned that you can take a blood test to see if you are in fact producing the anti-bodies against your baby. This seems like a good first step. Also, it seems like if she were to fall or get into an accident, this would precipate taking the shot becuase the chances that maternal and fetal blood have mixed are higher. In general, fetal and maternal blood don’t mix, again, a reason why the risks are relatively low with complications with the first child.

We also learned that you can have your baby tested at birth to see if he or she is RH positive (if the baby is RH negative Kerry won’t have a problem). If the baby is RH positive, then Kerry can take the shot at that time. (This needs to be done within 72 hours after birth)

Also of note, according to the March of Dimes almost all babies born with Rh disease will be cured, but it is still a very serious condition requiring a lot of intensive care — so, again, you have to weigh the pros and cons to receiving this shot. For me, I think I would do the blood testing at every step and, hoping to avoid pre-natal shots. I would consider taking the shot after my child was born if her blood was opposite of mine. But Kerry has to decided this for herself and it is definitely a difficult decision.