One of the most severe causes of this condition is rhesus incompatibility.
Other causes include, in descending order of frequency and severity:
Rhesus incompatibility tends to be more severe than ABO incompatibility because anti-D antibodies are mainly IgG, which can readily cross the placenta, whereas anti-A and anti-B antibodies are mainly IgM, which cannot cross the placenta.
Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.