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Risk factors for RhD immunisation despite antenatal and postnatal anti‐D prophylaxis
Author(s) -
Koelewijn JM,
de Haas M,
Vrijkotte TGM,
van der Schoot CE,
Bonsel GJ
Publication year - 2009
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.2009.02244.x
Subject(s) - medicine , pregnancy , caesarean section , obstetrics , gestation , vaginal delivery , risk factor , relative risk , pediatrics , gynecology , confidence interval , genetics , biology
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.