• Open Access

Risk factors for RhD immunisation despite antenatal and postnatal anti-D prophylaxis

Authors

  • JM Koelewijn,

    1. Sanquin Research, Amsterdam, and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands
    2. Division of Public Health, Academic Medical Centre, University of Amsterdam, the Netherlands
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  • M de Haas,

    1. Sanquin Research, Amsterdam, and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands
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  • TGM Vrijkotte,

    1. Division of Public Health, Academic Medical Centre, University of Amsterdam, the Netherlands
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  • CE van der Schoot,

    1. Sanquin Research, Amsterdam, and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands
    2. Division of Public Health, Academic Medical Centre, University of Amsterdam, the Netherlands
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  • GJ Bonsel

    1. Division of Public Health, Academic Medical Centre, University of Amsterdam, the Netherlands
    2. Department of Health Policy and Management, Erasmus Medical Centre, Rotterdam, the Netherlands
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Dr M de Haas, Sanquin Research, Amsterdam, and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Plesmanlaan 125, 1066 CX Amsterdam, the Netherlands. Email m.dehaas@sanquin.nl

Abstract

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.

Design  Case–control study.

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

Population  Cases: 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. Controls: 339 parae-1 without red cell antibodies.

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

Main outcome measure  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 (≥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.

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