Pregnancy check
Rh negative in pregnancy: which tests do I need?
If your blood is Rh-negative and your baby's is Rh-positive, your body can make antibodies against the baby's red blood cells. The US Preventive Services Task Force recommends tests that let this be prevented. Check what it says for you.
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What you will see
Which Rh tests the USPSTF recommends for you in this pregnancy.
Educational only, not medical advice. Your prenatal care team decides the tests and treatment for your pregnancy.
Source
US Preventive Services Task Force, February 2004 recommendation on screening for Rh(D) incompatibility (current, not under update as of 2026-10-31).
Validated in
Pregnant people at the first prenatal visit, and Rh(D)-negative pregnant people without Rh antibodies at 24 to 28 weeks.
Limits
It does not cover people who already have Rh antibodies, or when immune globulin is needed after bleeding, injury or procedures such as chorionic villus sampling. It is not a blood type test.
What the USPSTF recommends
| Who | Recommendation | Grade |
|---|---|---|
| All pregnant women, at the first pregnancy-related care visit | Rh(D) blood typing and antibody testing | A |
| Rh(D)-negative pregnant women without antibodies (unsensitized), at 24 to 28 weeks | Repeat Rh(D) antibody testing, unless the biological father is known to be Rh(D)-negative | B |
The USPSTF found good evidence that blood typing, antibody testing and Rh(D) immune globulin when needed prevent the parent from becoming sensitized and improve outcomes for newborns, and that the benefits substantially outweigh any harms (USPSTF 2004).
What Rh incompatibility is
Rh incompatibility happens when a pregnant person has Rh-negative blood and the baby has Rh-positive blood. Some of the baby's red blood cells can cross the placenta, and the parent's immune system may make antibodies against them. Those antibodies can cross back and destroy the baby's red blood cells, which can cause jaundice and, in severe cases, brain damage from high bilirubin or fluid buildup in the baby (MedlinePlus).
A first baby is often not affected, because it takes time to make antibodies, unless there was a past miscarriage or abortion. Later Rh-positive babies can be. With immune globulin (RhoGAM) given routinely, Rh incompatibility is almost completely preventable (MedlinePlus).
When immune globulin is given
For Rh(D)-negative people without antibodies, the USPSTF notes that a full dose (300 µg) of Rh(D) immune globulin is recommended after the repeat antibody test at 24 to 28 weeks. If the baby is Rh(D)-positive or weakly positive, another dose is recommended after birth, preferably within 72 hours (USPSTF 2004).
Unless the biological father is known to be Rh(D)-negative, a full dose is also recommended after amniocentesis and after an induced abortion or miscarriage; before 13 weeks, a 50 µg dose is enough. The benefit of routine immune globulin after other procedures or events, such as chorionic villus sampling, ectopic pregnancy, abdominal injury or bleeding from the placenta, was uncertain on the evidence the USPSTF had (USPSTF 2004). MedlinePlus lists injections after a miscarriage or abortion, after tests such as amniocentesis and chorionic villus sampling, and after injury to the abdomen during pregnancy (MedlinePlus).
Common questions
Do I need the test in every pregnancy?
Yes. The first-visit blood type and antibody test is recommended for all pregnant people, and the immune globulin is given in every pregnancy where it is needed (USPSTF 2004) (MedlinePlus).
I already know I am Rh-negative. Why test again?
The repeat test at 24 to 28 weeks checks that you have not started making antibodies since the first visit. The USPSTF found fair evidence that it adds benefit over a single test (USPSTF 2004).
What if the father is Rh-negative too?
The USPSTF makes an exception to the repeat test when the biological father is known to be Rh(D)-negative. It applies only when his Rh type is known, not assumed, so tell your prenatal care team what you know (USPSTF 2004).
Is this recommendation up to date?
It dates from 2004, when the USPSTF updated its 1996 advice and found no new evidence on screening, new tests, new treatment or harms. The USPSTF still lists it as the current final statement; we checked on 2026-10-31 (USPSTF 2004).
Also see the gestational diabetes screening check, the blood pressure in pregnancy check, the folic acid check and all screening tests by age.
Sources
- US Preventive Services Task Force. Screening for Rh(D) Incompatibility: Recommendation Statement. February 15, 2004. www.uspreventiveservicestaskforce.org/uspstf/recommendation/rh-d-incompatibility-screening
- MedlinePlus Medical Encyclopedia. Rh incompatibility. US National Library of Medicine. medlineplus.gov/ency/article/001600.htm
Written and maintained by the uncovermyrisk.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-10-31. Spotted an error? See About.