ABSTRACT
To determine the incidence of alloimmunization among pregnant women in Saudi Arabia Prospective study King Khaled University, Hospital, Riyadh, Saudi Arabia One thousand one hundred and ninty five pregnant women The rates of alloimmunization among pregnant women subjects by analyzing the blood type of both mother and neonate The largest fraction of alloimmunization involved Rh antigens [52.38%], while other groups such as Kell and Duffy play a less common role. Alloantibodies identified fivety pesofalloantibodiesin addition to nonspecific-autoantibodies. The most frequent [52.38%] were against Rhesus 2.38%; Kell 2.38%; Duffy 2.38%; 4.76% were non-specificantibodiesand33.3%were autoantibodies. Alloimmunization are: anti-D 28.57%, anti-C 4.76% anti-E 14.28% and anti-e 4.76%; only one 2.38% developed anti-K; anti-Jk, one 2.38%; one had anti-Le 2.38%; there was one 2.38% with anti-Fy. 1.84% of the total number of study subjects were alloimmunized by antigens of Rh while 0.08% were alloimmunized to antigens either from Kell, Kidd, Lewis or Dufffy. The relative importance of antigens other than Rh D have increased since the introduction of Rh D prophylactic treatment. Alloimmunization to E, c and Kell antigens can reach significantproportionsofstudied populations and can result in deleterious effects on fetus. The actual risk of alloantibody production during pregnancy is unknown but stimuli for antibody production are feto-maternal bleeds that occur throughout pregnancy