How to Pronounce Rh Incompatibility

Say it like this: 'ar-aych in-kom-pat-ih-BIL-ih-tee.' The stress falls on the last part—say 'BIL' the loudest. 'Rh' sounds like the letters 'R' and 'H' said separately, and 'incompatibility' rhymes with words ending in '-ibility' like 'ability.'

'Rh' is short for 'Rhesus,' named after the rhesus monkey where scientists first discovered this blood factor. You'll often see it written as 'Rh factor' or just 'Rh' on blood test results.

Break it like this: Rh in-com-PAT-i-BIL-i-ty. The word has seven syllables total, with the strongest stress on 'BIL' in the middle-to-end of the word.

Many people stress the wrong syllable and say 'in-kom-PAT-ih-bih-LIT-ee' instead of the correct 'in-kom-pat-ih-BIL-ih-tee.' Remember to put the emphasis on 'BIL,' not at the very end.

'Incompatibility' means 'not able to work or exist together.' In medical language, it refers to when two things (in this case, blood types) don't mix well with each other.

'Compatibility' means things that work well together or are suited to each other. 'Incompatibility' is the opposite—it means things that clash or don't go well together. The prefix 'in-' means 'not.'

Here's an example: 'The doctor explained that Rh incompatibility can occur when two different blood types are involved.' You might also hear people say 'Rh disease' or 'Rh problem' instead, but 'Rh incompatibility' is the full medical term.

There isn't one standard abbreviation, but you'll often see just 'Rh' or 'Rh disease' used as shorter ways to talk about this condition. The term 'hemolytic disease of the newborn' (or HDN) is also related and sometimes used in medical conversations.