Wednesday, February 6, 2008

Learning about Isoimmunity

Monday was my appointment with the Maternal Fetal Specialist. Doug and my mom came with me to see the baby and hear about possible complications we might face this pregnancy.

The first stop was in the ultrasound room, where we got to see a much bigger baby stretching, waving, hopping and moving around. The tech took several measurments, including one I wasn't expecting- the Nuchal Fold Measurment. The NF is the area on the back of the baby's neck. If it is above 3 mm, it can indicate a possibility of a genetic defect like Down syndrome or a neural tube defect like spina bifida. This baby's NF measurement was 1.5, well within the normal range. We got a few prints of the baby to bring home and share with everybody. It was too early to tell if it is a boy or girl, but Grampa Larry assures me that if it is a boy we'd surely be able to tell this soon. ;)

After a looooooong boring wait in the exam room, we met with the doctor. Apparently she had been waiting and waiting for my lab results from my regular OB to show up. She sat down with us to explain the isoimmunity condition we have and to set up a game plan for how she recommends monitoring it.

During the routine blood screening for my pregnancy last Spring, we found out that I have the antibodies E and Kell in my blood. Generally, these are only developed if a person has a blood transfusion with E and Kell positive blood or if a woman is exposed to it from a E and Kell positive pregnancy. I've never had a transfusion, so this led us to having Doug's blood tested to see if he is a carrier of the antigen E and Kell. We found out that he is, so one of our sons must also have it and exposed it to me. My blood reacted to the antigen by making an antibody (a protein to attach to the E and Kell proteins and attack them.) So far, the amount of the antibodies in my blood has been at a very low and relatively safe level.

The reason the doctors must be concerned about this, is because if the levels in my blood get higher, then can pass to the baby. If the baby is also E and Kell positive, then the antibodies in my blood can attach to the antigens in the baby's blood and start breaking down the proteins in it's blood. This could result to anemia, and worse, heart failure.

The plan is to get my blood drawn every moth to see if the antibody level rises. If the Kell level gets to 1:8 or the E gets to 1:16, then I will need to make regular visits to the specialist. They will do a special ultrasound test to measure the amount of blood flow to the baby's Middle Cerebral Artery (the main artery in the brain.) If it shows an increas of blood flow, then this is a sign that the baby is getting anemic. The next step would be an amniocentesis (a large needle draws fluid from the bag of waters) to measure the amount of bilirubin (the breakdown of blood cells) in the baby's blood. If that indicates a problem, the baby could require in utreo blood transfusions to fight off the antibodies.

Right now, my levels are low enough that the specialist said that she thinks this is unlikely to cause major complications. She is hopeful that I will be able to continue the pregnancy without further complications due to the isoimmunity. However, the baby will most likely be jaundice after birth and require some phototherapy to help break down the bilirubin. Sean and Aidan were also jaundice after birth, but only Sean required treatment and that was able to be done at home. We are hopefully that the baby will be fine.

Another interesting thing we learned, is that when Doug was tested for antigens, they did not test to find out if both sets of his DNA carry the antigen. He has to get the test repeated to find this out, because if both sets have it (she said its called homozygotic) then the baby will definitely have the same antigens. If only one set of his DNA has it (called hetrozygotic) then the baby has a 50/50 chance of getting the antigens. She frequently stated that we needed to find out if Doug was hetro or homo! Ha ha ha, gotta get humor where you can! If he is hetrozygotic, and the baby was made with the 50% that doesn't have those antigens, then thankfully the antibodies in my my blood will not cause any complications to the baby! Yay! Let's pray for that!

The doctor breifly talked about genetic testing with us and I stated that I was fine with getting amnio's done to check the well being of the baby due to the isoimmunity, but that we did not feel it was necessary for genetic testing. She was very comfortable in our answer and did not try to encourage me to change my mind.

Also, the sono tech said that the baby's measurements gave me an Aug 10th due date. The 6 wk sono tech gave me an Aug 19th due date. Based on the fertility charting I did, I have felt that Aug 15th is my due date. I decided I'm sticking with the 15th, though I am well aware that "when an apple is ripe, it will fall from the tree" as Grampa Larry quoted.


~Melissa~ said...

What great pictures! It sounds like the doctor has a good monitoring plan for you - I hope this pregnancy goes nice and smooth for you!

Mommy to those Special Ks said...

Continuing to pray for a safe pregnancy and a healthy, happy baby!

JennyH said...

Lots of info!
Great pictures of the baby. Hope everything stays calm the entire pregnancy.

Emily said...

I just found your blog through another DS related blog. My daughter Macy (DS)is 7 1/2 months old. I've been through 2 iso-immunized pregnancies. I have anti-D and anti-E antibodies. We found out about this right after my second son was born. We did not know that he was being affected by the antibodies until after his birth. He became extremely jaundiced and a little bit anemic but never required a blood transfusion (he did get one dose of IVIG). He is now a very healthy and strong 3 year old.

Going into my third pregnancy, I was closely monitored by a perinatologist. Starting at about 20 weeks, I had MCA doppler ultrasounds every week or 2 (depending on the last measurement) to check the velocity of blood flow through baby's brain. This is more accurate for determining anemia than titers. My baby (Macy) was fine and never did develop anemia. She was born at 37 week and started phototherapy right away for jaundice (5 days in the newborn nursery) then came home on bili-lights for a few more weeks. She never developed any anemia. We found out about the DS the day after she was born and that was a huge shocker after all the many ultrasounds I'd had (she also had a complete AV canal defect and a large VSD which wasn't caught on ultrasound).

If your baby does develop severe anemia (which my doc said about 10% do) you can receive an in-utero blood transfusion. Most of the time with proper monitoring things turn out well. I am not sure how strong of an anti-body kell is, but anti-E is typically one of the weaker ones. My baby's jaundice was mainly caused by anti-D.

Best wishes for a healthy pregnancy!

RK said...

Wow, this is stuff I know nothing about. You sound like you have a great handle on it though!