Introduction to alloimmune disorders of pregnancy
This tutorial costs £10.00
The alloimmune disorders of pregnancy are a range of conditions related by their underlying pathophysiological process. This process involves the immunisation of a woman against antigens, which may be expressed by her fetus leading to an immune destruction of fetal blood cells. Whilst each condition shares this underlying pathophysiology, they differ in the effect on the fetus.
RhD alloimmunisation is the condition most of you will be familiar with and remains the most common form of alloimmunisation in the UK. This area of our specialty can be confusing and intimidating to the trainee and the situation is not helped by terminology, which is interchangable and not always logical.
However, the principles for RhD alloimmunisation are the same for alloimmunisation to other red cell antigens such as K from the Kell system or Fya from the Duffy system, and similar to alloimmunisation to platelet or white cell antigens. We hope that by gaining a thorough understanding of these principles you will gain confidence in this subject area, be able to apply your knowledge and obtain appropriate advice in any clinical situation which may arise.
The aim of the diagram below is to give you an overview of the tutorial. Each section should relate to red cell antigens, platelet antigens and white cell antigens as pictured below.
In the 1960s, the incidence of haemolytic disease of the fetus and newborn was approximately one per 100 births and accounted for one in 2200 perinatal deaths. Since the introduction of anti-D prophylaxis and improved obstetric and neonatal techniques, the incidence has dropped to one in 21,000 births with between 25 and 30 deaths each year. Historically this has been an exciting area of medicine and impressive scientific steps are still being made, exampled by the advent of free fetal DNA to determine fetal genotype.
Consider a fetus facing certain death with severe anaemia secondary to red cell alloimmunisation which, following successful intrauterine transfusion, is then left with an entirely normal life expectancy. There can be few other areas in medicine where clinicians are able to diminish the effect of a disease to such an extent.
Learning objectives When you have completed this tutorial, you should have a better understanding of: - relevant blood cell antigen–antibody systems
- maternal alloimmunisation
- the effect of alloimmunisation on the fetus or neonate
- prevention and screening of alloimmune disorders in pregancy
- the management of alloimmune disorders in pregnancy.
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Last updated: 04/11/09 (new image and text added in the section on Antigens)
27/08/08 (new NICE technology appraisal guidance added in Preliminary reading and in the Prevention section).