I am writing this to help the many mothers-to-be that have written me about their Kell sensitive pregnancy and how it could have happened. I think the hardest thing for anyone in a modernized medical society to realize just how random and confusing the body still is. You can do every single thing “right”, and still have something go badly wrong. It sucks.
So, here is how you can have many healthy babies and then BLAM a fetus endangered by your Kell antibodies.
Say you have 9 kids and this is your 10th pregnancy and you never had any problems before but suddenly with this 10th pregnancy the OB/Gyn finds Kell antibodies in your blood. What happened? Well, ONE of your previous pregnancies was Kell positive and you didn’t know.
If the dad is Kk, any baby that gets the K is positive for the Kell antigen and any baby that gets the little k is Kell negative. There is a 50/50 shot of inheritance, but random chance will show how easy it is to get 5 little k genes in a row, or vice versa. Think of flipping coins … do you ALWAYS get 50% heads and 50% tails when you toss it ten times in a row? Nope. You can have 100% heads and other than looking a little weird, it falls within the “normal” outcome.
Thus, if these mythical ten pregnancies were “k k k K k k k k K” then baby #4 would have “sensitized” the mother but would NOT have shown any problems, and the three Kell negative children after him/her would have been fine, but Kell positive baby #10 will activate the now-sensitized antibodies to attack him/her in the womb. There is NOTHING anyone could have done to prevent this.
Likewise, if the babies were “k K k k K K K K K” and the new pregnancy was “k”, then the 10th pregnancy would be fine despite the 5 alloimmunized pregnancies before it. Again, there is nothing the parents can do either way except cross their fingers and pray for little k carrying sperm to swim the fastest.
I hope this helps moms understand how they had no control over whether or not they have or had a K-sensitized high-risk pregnancy and finding the answers to WHY they have a Kell sensitized pregnancy cannot help them avoid another one.