I started my pregnancy with my third child knowing that it would be riskier than before–after all, I was 38 years old, and my other children were 12 and nine at the time.
Being an experienced mother who had delivered at two crowded teaching hospitals, I wanted a smaller clinic and smaller hospital. The first doctor I turned to for my prenatal care was a family care practitioner with obstetrician privileges. At 10 weeks, I had a standard round of bloodwork.
When my doctor did not call me back within a matter of a few days, I worried. Finally, my doctor called me and told me that I had tested positive for something called “anti-Kell” and my titer was 64.
What is anti-Kell?? I had never heard of this. What is a titer? I was not familiar with this; I had never heard the word!
The reason for the delay, my doctor explained, was that she had never had an anti-Kell patient in her seven years of practicing medicine, and she wanted to further research the condition before giving me information about it. I appreciated that. My doctor told me that I had developed Kell antibodies after being exposed to blood that contained the Kell antigen (protein). My body made these antibodies to fight off foreign cells–in this case, blood cells of a developing fetus.
Learn more about HDFN testing and diagnosis
Learning my baby may be at risk
My doctor told us my titer is a measurement of the presence of Kell antibodies in my blood. A titer of 64 was way past the “critical” level of four, and I needed to see a maternal-fetal medicine specialist for further monitoring. My doctor explained that this blood condition, known as alloimmunization, makes me high-risk. My antibodies could cross the placenta and destroy my baby’s red blood cells if my baby had inherited the Kell antigen.
My husband and I were also told that there was an increased risk of second trimester loss, stillbirth or our baby needing a blood transfusion before or after birth. Since these antibodies are often caused by blood mixing during a pregnancy with a Kell-positive fetus (meaning the baby has inherited the red blood cell Kell antigen from the father), my husband had a simple blood test that showed that he was in fact a carrier for the Kell antigen.
The next day, he had another blood test which revealed that all of our children hold a 50% chance of inheriting the Kell antigen, therefore a 50% chance of being at risk for HDFN.
Advocating for my family’s medical needs
I was devastated and terrified, but I wanted to learn everything I could. As a patient, I have always been the type to not want any information spared; I wanted to be aware and “in the know”. My doctor referred me to a maternal-fetal medicine specialist (MFM).
And what do women do when we need more information? We ask. We read. We research. We are pretty good at this, aren’t we? However, due to the rarity of anti-Kell, patient-friendly information, even on the internet, was not easily accessible.
I joined an online support group for moms with various types of antibodies during pregnancy. I started seeing an MFM, but she was inexperienced with anti-Kell and we were not on the same page about my care plan.
I switched doctors again. I began having weekly advanced ultrasounds called middle cerebral artery dopplers (MCAs). The technician took measurements of the blood flow through the baby’s brain to determine whether fetal anemia could be developing. In this case, we had to assume the baby could be a genetic carrier for the Kell antigen.
We had the option of noninvasive blood testing called cffDNA, which is very accurate, to see whether our baby inherited the Kell antigen and was at risk for HDFN. The other option for genetic testing was amniocentesis, but we did not feel comfortable with this. I would later learn that amniocentesis is not the best way for alloimmunized mothers to have fetal testing (in this case, genotyping) done.
As it turns out, amniocentesis, although incredibly useful as a diagnostic tool, is quite risky for alloimmunized moms. It can cause sudden spikes in your antibody titer, which can lead to further clinical confusion about your baby’s antigen status. In addition, like some other prenatal procedures, amniocentesis can subject the mother to potential further alloimmunization against other alloantibody types, such as anti-D, anti-c, for example. Some types are more severe and unpredictable than other types.
Although I declined fetal testing through amniocentesis, I intended on educating myself on cffDNA. I would soon learn much more about testing and monitoring, which would heavily influence the course of my high-risk care.
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