Rhesus Negative Pregnancy: What It Means
Being Rhesus negative in pregnancy explained simply, including sensitisation, antibodies, and how Anti-D protects future babies.
Table of Contents
- What Rhesus Negative Means for You
- How Rhesus Negative Pregnancies Are Managed
- Frequently Asked Questions
What Rhesus Negative Means for You
If your booking blood test shows you are Rhesus negative (RhD negative), it simply means your red blood cells lack the RhD protein that most people carry. It is not a disease and does not affect your day-to-day health. The reason it matters in pregnancy is that your baby may inherit the RhD positive trait from the other parent. If any of your baby blood cells mix with yours, your immune system may treat them as foreign and create antibodies. This is called sensitisation and usually happens during birth, bleeding, or trauma, but can also occur without an obvious trigger.
How Rhesus Negative Pregnancies Are Managed
To stop your body making antibodies, you will be offered Anti-D immunoglobulin injections, typically at 28 weeks and within 72 hours of birth if your baby is confirmed RhD positive. You may also receive Anti-D after any bleeding, abdominal trauma, or invasive procedure such as amniocentesis. Your midwife will check your blood for antibodies at booking and again at 28 weeks. If antibodies are detected, you will be referred to a specialist fetal medicine team for closer monitoring, because they can cause anaemia in the baby in later pregnancies.
Frequently Asked Questions
Will being Rhesus negative affect my first baby?
Sensitisation rarely affects a first pregnancy because the baby blood cells rarely cross over before birth. Anti-D is still offered as a precaution to protect future pregnancies.
Can I refuse Anti-D injections?
Yes, Anti-D is a blood product and you can decline it. Your midwife will explain the risks so you can make an informed choice. Without Anti-D, there is a higher chance of sensitisation affecting future pregnancies.
What happens if I already have antibodies?
If antibodies are found, your care moves to a specialist team. You may have extra scans to check your baby for anaemia, and in rare cases the baby may need treatment before or shortly after birth.
This information is for educational purposes only and is not a substitute for professional medical advice. Always consult your midwife, GP, or obstetrician about your individual results and care plan.
Further reading:
Related articles: Early Pregnancy Blood Tests | hCG Levels Explained | Anaemia in Pregnancy