Blood Test For Rh Status And Antibody Screen during Pregnancy
The Rh factor test is done during pregnancy to recognize a woman’s Rh factor. In many cases, the baby’s daddy may require an Rh factor test, too.
Rh Negative or Positive Blood Test Understanding
Early in your pregnancy your blood will be evaluated to identify your blood type and your Rh status– that is, whether you have the Rh (Rhesus) factor, a protein that most people have on the surface of their red blood cells.
If you do have the Rh factor, as many people do, your status is Rh-positive. (About 85 percent of Caucasians are Rh-positive, as are 90 to 95 percent of African Americans and 98 to 99 percent of Asian Americans.) If you do not have it, you’re Rh-negative, and you’ll need to take specific precautions during your pregnancy.
If you’re Rh-negative, there’s a good chance that your blood is incompatible with your baby’s blood, which is likely to be Rh-positive. You most likely will not know this for sure until the baby is born, but for the most parts you have to assume it, just to be safe.
Being Rh-incompatible isn’t likely to damage you or your baby during this pregnancy, if it’s your first. But if your baby’s blood leakages into yours (as it can at certain times during pregnancy and at birth), your immune system will begin to produce antibodies versus this Rh-positive blood. If that occurs, you’ll end up being Rh-sensitized– and the next time you’re pregnant with an Rh-positive baby, those antibodies might attack your baby’s blood.
Thankfully, you can prevent ending up being Rh-sensitized by getting an injection of a drug called Rh immune globulin whenever there’s an opportunity that your blood has actually been exposed to the baby’s blood.
If you’re Rh-negative and you’ve been pregnant before however didn’t get this shot, another regular prenatal blood test will inform you whether you currently have the antibodies that attack Rh-positive blood. (You might have them even if you miscarried the baby, had an abortion, or had an ectopic pregnancy.)
If you do have the antibodies, it’s too late to obtain the shot, and if your baby is Rh-positive, he’s most likely to have some issues. If you don’t have the antibodies, then the shot will keep you from establishing them.
What are the opportunities that my baby and I are Rh-incompatible?
If your baby’s dad is Rh-positive– as most people are– you have about a 70 percent opportunity of having an Rh-positive baby. So if you’re Rh-negative, it’s likely that you and your baby are Rh-incompatible. In truth, your healthcare specialist will presume you are, just to be safe. There’s no harm in getting the Rh immune globulin shot, even if it turns out that it wasn’t essential.
Naturally, if your baby’s daddy has actually been evaluated and discovered to be Rh-negative, too, then your baby will likewise be Rh-negative and you will not need the shot. But if your baby’s dad is Rh-positive (or you do not know whether he’s favorable or unfavorable), you will not know your baby’s Rh status for sure up until her birth unless you have an amniocentesis, a test that examines fetal cells from the amniotic fluid surrounding the baby in your uterus.
On the other hand, if you’re Rh-positive and your husband is Rh-negative, you might have an Rh-negative child. Despite this distinction, there’s no need to worry, due to the fact that it’s very not likely that your baby will be exposed to your blood and develop antibodies. It often happens the other method around.
How could my baby’s blood leak into mine?
Usually during pregnancy, your baby’s blood stays separate from yours and very few blood cells cross the placenta. In fact, your blood is not most likely to intermingle in any substantial method till you give birth. That’s why Rh incompatibility is usually not an issue for your first baby: If your blood does not blend up until you’re in labor, the baby will be born prior to your immune system has an opportunity to produce enough antibodies to cause problems.
Nevertheless, you’ll need a shot after the birth if your newborn is found to be Rh-positive. If you were exposed to Rh-positive blood during delivery, the shot will prevent your body from making antibodies that might attack an Rh-positive baby’s blood during a future pregnancy.
Your delivery team will take a blood sample from your newborn’s heel or from his umbilical cable just after he’s born to test for a number of things, including Rh factor, if required.
Without treatment, there’s about a 15 percent opportunity that you’ll produce antibodies, however with treatment, the possibility is close to 0 percent.
Because a little number of Rh-negative women (about 2 percent) in some way develop antibodies to their baby’s Rh-positive blood during their 3rd trimester, you’ll also be given shot of Rh immune globulin at 28 weeks that covers you till giving birth. And you’ll require a shot other time that your baby’s blood might mix with yours, consisting of after an invasive procedure, such as an amniocentesis or chorionic villus tasting (CVS), or if you have:.
- an ectopic pregnancy.
- an abortion.
- a molar pregnancy.
- an injury to your abdomen during pregnancy.
- a miscarriage.
- vaginal bleeding.
- an external cephalic version (ECV).
- a stillbirth.
If you discover yourself in any of these circumstances, advise your caretaker that you’re Rh-negative, and make sure you get the shot within 72 hours.
How does the shot prevent me from developing antibodies?
The Rh immune globulin shot consists of a small dosage of antibodies, gathered from blood donors. These antibodies eliminate any Rh-positive blood cells in your system, which appears to keep your immune system from developing its own antibodies. The donated antibodies are similar to yours, however the dose isn’t really big enough to cause problems for your baby.
This is called passive immunization: For it to work, you have to get the shot no more than 72 hours after any possible direct exposure to your baby’s blood. The defense will last for 12 weeks. If your professional believes that more than an ounce of your baby’s blood blended with yours (say, if you’ve had a mishap), you may require a 2nd shot.
You’ll get the injection in the muscle of your arm or butts. You may have some soreness at the injection site or a slight fever. There are no other known side effects. The shot is safe whether your baby’s blood is really Rh-positive or not.
What will happen to my baby if I develop the antibodies?
First, bear in mind that this is highly not likely if you’re receiving good prenatal care and are being treated with Rh immune globulin when necessary. Even without treatment, your chances of developing the antibodies and ending up being Rh-sensitized are only about 50 percent after several Rh-incompatible pregnancies.
If you didn’t get the shot, though, and you ended up being Rh-sensitized and your next baby is Rh-positive, he would most likely establish Rh disease (hemolytic disease). Your antibodies would cross the placenta and attack the Rh consider your baby’s Rh-positive blood as if it’s a foreign compound, damaging his red blood cells and causing anemia. The disease can cause issues varying from severe newborn jaundice to brain damage or, in severe cases, miscarriage or stillbirth.
Once you’re sensitized, you have the antibodies forever. And you produce more with each pregnancy, so the risk of Rh disease is higher for each subsequent baby. While healthcare providers attempt to screen and treat as numerous women as they can reach, about 5,000 children establish Rh disease in the United States every year.
Fortunately is that doctors are discovering brand-new ways to conserve babies who develop Rh disease. Your professional can monitor your level of antibodies and keep tabs on your baby’s condition during pregnancy to see whether he’s developing the disease. She might examine the condition of your baby’s red blood cells using Doppler ultrasound or amniocentesis.
If he’s succeeding, you might be able to bring him to describe without complications. After birth, he might be provided what’s called an exchange transfusion to replace his unhealthy Rh-positive red blood cells with healthy Rh-negative cells. This stabilizes the level of red cell and reduces more damage by antibodies flowing in his blood stream.
With time these Rh-negative blood cells will pass away off and all your baby’s red cell will be Rh-positive once again, however by that time, the attacking antibodies will be gone.
If your baby’s in distress, he might be delivered early or offered transfusions through the umbilical cord. The survival rate for babies who receive a transfusion in utero is as high as 80 to 100 percent, unless they have hydrops (an issue brought on by severe anemia), in which case the chances of survival are about 40 to 70 percent.
Last modified: October 23, 2016