Rhesus alloimmunization in pregnancy. A tertiary care center experience in the Western region of Saudi Arabia.
OBJECTIVE
To determine the distribution of ABO blood group and rhesus (RH) factor among pregnant women, to estimate the prevalence of Rh alloimmunization, and report the perinatal outcome of all cases of Rh alloimmunization at King Abdul-Aziz University Hospital (KAUH).


METHODS
This is a retrospective study of pregnant women attending the antenatal clinics in KAUH, Jeddah, Saudi Arabia  between January 2004 and December 2009. Records of patient diagnosed as Rh negative blood group were reviewed for the presence of antibodies, antibodies titer, and progress in the level of antibodies. Maternal and neonatal outcomes were reported.


RESULTS
Twenty-four thousand and five pregnant women were included in this study. The most common blood group was O followed by A, B and AB positive. Rhesus negativity blood group was reported in 7.5%. Four hundred and twenty-four cases were reported as Rh antibody positive with a prevalence of alloimmunization of 1.8% in the studied population, and 23.6% among Rh negative women. The perinatal mortality rate was 250 per 1000 in alloimmunized women compared to 17 per 1000 in the study population.


CONCLUSIONS
Blood group O positive is the most prevalent blood group among pregnant women attending our antenatal clinics and the prevalence of Rh negativity was 7.5%. The prevalence of Rh alloimmunization in the present study was 10-folds higher than that reported in the developed countries. Rhesus alloimmunization represent an avoidable direct cause for perinatal morbidity and mortality in our population.
Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Princes Al-Johra Center of Excellence for Genetic Disease, King Abdul-Aziz University, College of Medicine, PO Box 80215, Jeddah 21589, Kingdom of Saudi Arabia. bondagji_nabeel@hotmail.com
Nabeel S
NS
Bondagji
D000017:ABO Blood-Group System; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D012204:Rh-Hr Blood-Group System / Q000276:immunology*; D012529:Saudi Arabia
D000017:ABO Blood-Group System; D012204:Rh-Hr Blood-Group System