Q&A: In my last two pregnancies I had Rh negative blood, but now a test is saying I am O positive.
I am Rh- and have had numerous late menstrual cycles interspersed with my normal 30-day ones. Twice I even spotted when I was about one week late, only to have moderate to heavy bleeding a week later. I have had two successful pregnancies with Rh+ babies born. I assume that I have become Rh sensitive through: miscarriage, possibly not having been given Rhogam after my second delivery, or that the Rhogam after the second delivery wasn't effective due to the excessive bleeding I experienced.
For some reason, home pregnancy tests (performed even long after my cycle is late) have never been accurate for me, even when I was pregnant with the twins. So, determining if I am pregnant before the heavy bleeding begins cannot be done accurately in my own home.
My questions are:
- Can I expect to successfully carry another child belonging to my husband, who is Rh+?
- Can I expect to conceive an Rh- child with my Rh+ husband?
- Can I get an Rh antibody titre done when I am not pregnant that will show if I am Rh sensitive?
Yes, a simple blood test can tell you whether you have antibodies (anti-RH). If not, then you’re O.K. If so, then you’ve had exposure or (as you suggested) with so much bleeding with your previous delivery, the usual amount of RhoGam didn’t cover it. If you’ve been “Rh-sensitised,” then your subsequent baby is at risk.
The blood test, though, will give you this simple answer.
If your husband is Rh+, then he could either father a Rh+ or a Rh- child, assuming his genetics or mixed. If he’s “all” Rh+, two genes out of two, then he’ll only make Rh+ babies with you.