Rhesus negative is not a separate blood group like A, B, AB, or O; it simply means a person’s blood type does not have the Rh (Rhesus D) antigen, so their type is written with a “−” sign (for example A−, O−, B−, or AB−).

What “rhesus negative” means

  • Human blood types are described using two systems together: the ABO group (A, B, AB, O) and the Rh factor (positive or negative).
  • Someone who is “rhesus negative” (RhD negative) lacks the Rh (D) antigen on the surface of their red blood cells, so their full type is one of A−, B−, AB−, or O−.

Is rhesus negative a rare type?

  • Rh‑negative blood is relatively uncommon; for example, some blood services report only a small percentage of donors are Rh negative compared with Rh positive.
  • Group O Rh‑negative (O−) is particularly important in emergencies because it can often be used when there is no time to check a patient’s exact type.

Why it matters in pregnancy and transfusion

  • In pregnancy, problems can arise if a mother is Rh‑negative and the baby is Rh‑positive, because the mother can form antibodies against Rh‑positive cells (this is the basis of “Rhesus disease”).
  • For transfusions, Rh‑negative people are usually given Rh‑negative blood only, to avoid developing antibodies that could cause serious reactions.

In short: “What blood type is rhesus negative?” → Any ABO type (A, B, AB, O) that is RhD‑negative, written with a minus sign, such as O− or A−.

Information gathered from public forums or data available on the internet and portrayed here.