Rh antibodies in pregnancy
Rh antibody test · Rh incompatibility · antibody screen in pregnancy · antibody titer
This blood test shows whether the mother has antibodies against the baby's Rh-positive blood. It is done for women with Rh-negative blood.
For mothers with Rh-negative blood: during pregnancy, before the protective shot, and after bleeding or an injury.
⏱ Duration: the blood draw usually takes 5 minutes; results usually come in 1 to 3 days
Be sure to tell your doctor
How to prepare
- Food. You usually do not need to fast. If you are having other tests too, check with the lab.
- Schedule. Your doctor will tell you how many times to test. Usually several times during pregnancy.
- Protective shot. Immunoglobulin is usually given at about 28 weeks and after birth. Your doctor decides the timing.
What to bring
- Your referral
- Your pregnancy record card
- Past antibody results
How it goes
- You sit down, and a band is tied above your elbow
- The skin is wiped with antiseptic
- Blood is taken from a vein into a tube
- The band is removed, and a cotton pad is pressed on the spot
What you'll feel
- A quick prick, like a pinch
- If you feel dizzy, tell the nurse. They will help you lie on your side
Afterwards
- Press the cotton pad for 3 to 5 minutes
- Results usually come in 1 to 3 days
- If antibodies are found, the doctor will check the baby by ultrasound more often
- If there are no antibodies, the doctor will tell you when to get the protective shot
Contact a doctor straight away if
- Bleeding, a blow, or a fall onto your belly: tell your doctor right away. You may need the protective shot
- Severe belly pain or heavy bleeding: call emergency services
- The baby is moving much less: see a doctor right away
Common questions
I am Rh-negative. Is that dangerous for my baby?
Usually not, if you do your tests on time and get the protective shot. Your doctor watches this throughout the pregnancy.
Why the shot if there are no antibodies?
It stops antibodies from forming. It protects this baby and future children.