Risk factors for RhD immunisation despite antenatal and postnatal anti-D prophylaxis.
OBJECTIVE
To identify risk factors for Rhesus D (RhD) immunisation in pregnancy, despite adequate antenatal and postnatal anti-D prophylaxis in the previous pregnancy. To generate evidence for improved primary prevention by extra administration of anti-D Ig in the presence of a risk factor.


METHODS
Case-control study.


METHODS
Nation-wide evaluation of the Dutch antenatal anti-D-prophylaxis programme.


METHODS



METHODS
42 RhD-immunised parae-1, recognised by first-trimester routine red cell antibody screening in their current pregnancy, who received antenatal and postnatal anti-D Ig prophylaxis (gifts of 1000 iu) in their first pregnancy.


METHODS
339 parae-1 without red cell antibodies.


METHODS
Data were collected via obstetric care workers and/or personal interviews with women.


METHODS
Significant risk factors for RhD immunisation in multivariate analysis.


RESULTS
Independent risk factors were non-spontaneous delivery (assisted vaginal delivery or caesarean section) (OR 2.23; 95% CI:1.04-4.74), postmaturity (>or=42 weeks of completed gestation: OR 3.07; 95% CI:1.02-9.02), pregnancy-related red blood cell transfusion (OR 3.51; 95% CI:0.97-12.7 and age (OR 0.89/year; 95% CI:0.80-0.98). In 43% of cases, none of the categorical risk factors was present.


CONCLUSIONS
In at least half of the failures of anti-D Ig prophylaxis, a condition related to increased fetomaternal haemorrhage (FMH) and/or insufficient anti-D Ig levels was observed. Hence, RhD immunisation may be further reduced by strict compliance to guidelines concerning determination of FMH and accordingly adjusted anti-D Ig prophylaxis, or by routine administration of extra anti-D Ig after a non-spontaneous delivery and/or a complicated or prolonged third stage of labour.
Koelewijn
J M
JM
Sanquin Research, Amsterdam, and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands.
de Haas
M
M
Vrijkotte
T G M
TG
van der Schoot
C E
CE
Bonsel
G J
GJ
D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006401:Hematologic Agents / Q000627:therapeutic use*; D006801:Humans; D007518:Isoantibodies / Q000008:administration & dosage / Q000627:therapeutic use*; D009426:Netherlands; D011181:Postnatal Care; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000209:etiology / Q000517:prevention & control*; D011261:Pregnancy Trimester, First; D011295:Prenatal Care; D012203:Rh Isoimmunization / Q000209:etiology / Q000517:prevention & control*; D018029:Rho(D) Immune Globulin; D012307:Risk Factors; D055502:Secondary Prevention
D006401:Hematologic Agents; D007518:Isoantibodies; C061961:RHO(D) antibody; D018029:Rho(D) Immune Globulin