Announcing a Blood Test for the Rh Negative Mother (that lets you know if your baby is negative or positive)
I receive more questions about Rhogam via my contact form than another other topic on the site. If you’re an Rh negative woman and you’re not sure about Rhogam, this will probably excite you as much as it did me.
I’ve always declined prenatal Rhogam because I just didn’t feel comfortable with it for my babies.
I had it following the births of my first three babies… after a rush to get their cord blood tested at the lab, and get the Rhogam to my house or myself to hospital outpatient for one shot. I didn’t get it after my fourth baby because he’s Rh-, but I did have the anxious wait on the lab results to see if I needed the shot or not.
A relatively new test, on the market for about two years now, can completely remove all of this rush and anxiety. If you’re not sure about Rhogam prenatally it can help you determine if you may have a true need for it (you’re carrying a positive baby) – or if there’s no point in getting it (you have a negative baby).
If your test result does show your baby to be RhD+ (positive) you can go on and weigh the pros and cons of Rhogam prenatally and postpartum. If you need to plan to have Rhogam after a home or birth center birth you can firm up your plans now and save a lot of stress in the postpartum time.
Lenetix Medical Screening Laboratory, Inc. has released the RhD Genotyping Screen. It can determine if your baby is rh- or rh+ during pregnancy. It’s a maternal blood screen – this means blood is drawn from you and tested. Nothing ever touches your unborn child – it’s completely non-invasive.
As a bonus to finding out your baby’s Rh status, the test also finds the sex of your baby. If, of course, you want to know
Q & A with Lenetix’s President and CEO
Leonard H. Kellner, President and CEO of Lenetix answered some questions about the RhD Genotyping Screen for me (his answers are bolded):
Is it available now?: Yes, for two years now.
Would a woman be able to request the test from her OB/GYN or family doctor? Yes, all she needs to do is have her healthcare provider give us a call and we will send out supplies.
Is the blood drawn at her practitioner’s office/local lab and sent to your labs? Yes, that’s correct
How accurate is the test? 98%
Are any insurances covering the test? Yes
Does the test also identify fetal sex? Yes
Are the results shared with the mother? Yes
Why does the test need to be repeated if it shows a RhD- female fetus? It is only repeated when the fetus appears to be female and RhD negative, while (a female RhD negative) is the most likely result; the other reason could be no fetal DNA in the maternal plasma. The result would be the same since the mom is RhD negative and female, therefore there is no target for us to see.
I see that the test can be performed starting at 15 weeks fetal age – can it be done throughout the rest of pregnancy? Yes, and we have now collected data that it can be done much earlier and we have obtained results as early as 9 weeks.
I used the genotyping service during my pregnancy with Honor. Here are my thoughts on the initial testing:
I decided to go ahead and have the RhD genotyping done for our baby. My family doctor ordered the test for me since our prenatal care is with a homebirth midwife. A nurse drew the needed blood samples right in my family doctor’s office. Scott and I are waiting on the results now – hopefully we will get them next week.
The blood draw was easy for me, comparable to typical prenatal workups. It does require 4 vials of blood, so I would recommend eating well before going to the appointment, and if you’re like me and need to sit for a few minutes after having blood drawn, to plan for it to take a little longer while you sit!
As of right now Lenetix requests that the mother be at least 15 weeks along – I had mine done at 15 weeks and 7 days. The blood sample is overnighted to Lenetix Labs, which will bill insurance on your behalf. I’ll keep you updated with our results and how smoothly things go with our insurance
And read my follow-up blog post after Honor was born: RhD Genotyping Follow-up.