Implementation of routine screening for Kell antibodies: does it improve perinatal survival?

BACKGROUND

In 1998 a national program for first-trimester screening for red cell (RBC) antibodies in all pregnant women was implemented. The aim of our study was to assess the impact on perinatal mortality caused by Kell alloimmunization

STUDY DESIGN AND

METHODS

Prospectively collected data on all pregnant women referred to our center from 1988 until 2005 for intrauterine transfusion (IUT) for fetal anemia due to Kell alloantibodies were analyzed. The cohort was divided into two groups, those treated before 1998 and those treated after 1998. The primary outcome was fetal and neonatal survival. Secondary outcome variables were gestational age, fetal hemoglobin (Hb) levels at first IUT, severity of hydrops, and total number of IUTs per pregnancy. Causes for mortality were analyzed in detail.

RESULTS

A total of 43 pregnancies were included, 18 before introduction of screening and 25 thereafter. Perinatal survival increased from 61 percent in the first period to 100 percent after introduction of screening. After 1998, fetal hydrops was generally less severe at first IUT, while gestational age and fetal Hb levels at first IUT were similar.

CONCLUSION

Implementation of routine screening for Kell antibodies in pregnancy was associated with an increased referral rate for suspected fetal anemia, more timely referrals, and a higher perinatal survival rate after intrauterine treatment.