CircleBumpCheckedFilledMedicalBookmarkBookmarkTickBookmarkAddCheckBoxCheckBoxFilled

How Do I Know if I’m Rh Negative or Rh Positive?

What does it mean if I'm Rh negative or Rh positive? Do I have to get tested?
save article
profile picture of The Bump Editors
Updated March 2, 2017
Hero Image

At your first prenatal appointment, your OB will take blood for a long list of screenings. One of them will be to determine your blood type. You may already know if you’re  type A or O, but what’s important during pregnancy is whether or not you’re “positive” or ”negative.” Your OB will test your blood for Rh, a protein present in about 85% of the population. If you’re  Rh-negative and the father is Rh-positive, the fetus can inherit the Rh factor from the father. This makes the fetus Rh-positive too. Problems can arise when the fetus’s blood has the Rh factor and the mother’s blood does not. So, baby is “positive” but you are “negative”. If this happens, it’s possible for you to develop antibodies to your baby, in essence your body will think it’s allergic to baby. To prevent any complications,  you’ll need injections of a medication called RhoGAM at 28 or 29 weeks and within 72 hours after delivery to prevent problems.

Please note: The Bump and the materials and information it contains are not intended to, and do not constitute, medical or other health advice or diagnosis and should not be used as such. You should always consult with a qualified physician or health professional about your specific circumstances.

save article
ADVERTISEMENT

Next on Your Reading List

pregnant woman lying on exam table getting an ultrasound
Your Complete Guide to Pregnancy Ultrasounds
Medically Reviewed by Kendra Segura, MD
pregnant woman holding photo of ultrasound
What Is the Nuchal Translucency Ultrasound?
Medically Reviewed by Kendra Segura, MD
pregnant woman getting an ultrasound
Why You Might Need a Biophysical Profile in Pregnancy
Medically Reviewed by Kendra Segura, MD
ADVERTISEMENT
gynecologist checking pregnant woman's cervix in exam room
Is a Cervix Check Always Necessary in Late Pregnancy?
Medically Reviewed by Kendra Segura, MD
Your Complete Guide to Prenatal Testing
Your Complete Guide to Prenatal Testing
Medically Reviewed by Kendra Segura, MD
overhead view of woman getting first trimester ultrasound
Everything You Need to Know About the First Trimester Screening
By Dani Wolfe
Understanding the Glucose Screening and Glucose Tolerance Test
Understanding the Glucose Screening and Glucose Tolerance Test
Medically Reviewed by Kendra Segura, MD
ADVERTISEMENT
fetal doppler heart rate of in utero baby
Are At-Home Fetal Dopplers Safe?
Medically Reviewed by Kendra Segura, MD
black and white image of a family ancestry tree
Your Guide to Genetic Testing During Pregnancy
By Ashley Zielger
lab technician holding vial of blood for blood testing
FDA Report Warns Against False Positives in Some Prenatal Genetic Tests
By Nehal Aggarwal
ADVERTISEMENT
Same sex pregnant couple at home with their daughter on the couch.
What Is Amniocentesis?
By Rachel Morris
Pregnant woman and her partner happily looking at their sonogram.
Sonogram vs. Ultrasound: What’s the Difference?
By Christin Perry
medical doctor speaking with patient
3D Ultrasound: Why It’s Used and What You Can Expect to See
By Korin Miller
ADVERTISEMENT
Q&A: Why CVS/amnio?
Q&A: Why CVS/amnio?
By Paula Kashtan
pregnant woman in kitchen by window looking at her phone
Rh Incompatibility: What to Know if You’re Rh Negative and Pregnant
By Lexi Dwyer
happy couple looking at positive pregnancy test
11 Moms-to-Be Share What They Did With Their Positive Pregnancy Tests
By Ashlee Neuman
pregnant woman looking at sonogram
There May Be a New Noninvasive Way to Diagnose Fetal Genetic Disorders
By Ashley Edwards Walker
ADVERTISEMENT
crate full of fresh veggies and fruits
Here’s How to Tell if Baby Is at Risk for Childhood Obesity During Pregnancy, Study Says
By Stephanie Grassullo
pregnant woman personal story, skipping amnio test
Why I Skipped an Amnio Even Though I Was High-Risk
By Joanne Chen
doctor speaking with female patient medical office
Your Comprehensive Guide to Non-Invasive Prenatal Testing
By Rachel Morris
ADVERTISEMENT
Article removed.
Article removed.
Name added. View Your List