Premium
Third trimester screening for alloimmunisation in R hc‐negative pregnant women: evaluation of the D utch national screening programme
Author(s) -
Slootweg YM,
Koelewijn JM,
Kamp IL,
Bom JG,
Oepkes D,
Haas M
Publication year - 2016
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 - 10.1111/1471-0528.13816
Subject(s) - medicine , obstetrics , prospective cohort study , odds ratio , pregnancy , confidence interval , cohort , amniocentesis , antibody , fetus , gynecology , immunology , prenatal diagnosis , biology , genetics
Objective To evaluate the effect of red blood cell ( RBC ) antibody screening in the 27th week of pregnancy in Rhc‐negative women, on detection of alloimmunisation, undetected at first trimester screening (‘late’ alloimmunisation), and subsequent haemolytic disease of the fetus and newborn ( HDFN ), to assess risk factors for late alloimmunisation. Design Prospective cohort and nested case–control study. Setting The Netherlands. Population Two‐year nationwide cohort. Methods Prospective inclusion of Rhc‐negative women with negative first trimester screening and of screen‐negative controls. Assessment of incidence and numbers needed to screen ( NNS ) of late alloimmunisation and HDFN ; logistic regression analysis to establish risk factors for late alloimmunisation. Main outcome measures Late alloimmunisation, HDFN . Results Late alloimmunisation occurred in 99 of 62 096 (0.159%) Rhc‐negative women; 90% had c/E antibodies and 10% non‐Rhesus antibodies. Severe HDFN (fetal/neonatal transfusion) occurred in two of 62 096 (0.003%) of Rhc‐negative women and 2% of late alloimmunisations; moderate HDFN (phototherapy) occurred in 20 children [22.5%; 95% confidence interval ( CI ), 13.8–31.1%]. Perinatal survival was 100%. The NNS to detect one HDFN case was 2823 (31 048 for severe, 3105 for moderate HDFN ). Significant risk factors were former blood transfusion [odds ratio ( OR ), 10.4; 95% CI , 1.14–94.9], parity ( P −1: OR , 11.8; 95% CI , 3.00–46.5; P > 1: OR , 7.77; 95% CI , 1.70–35.4) and amniocentesis/chorionic villus sampling during current pregnancy ( OR , 9.20; 95% CI , 1.16–72.9). Conclusions Additional screening of Rhc‐negative women improved the detection of late alloimmunisation and HDFN , facilitating timely treatment, with a NNS of 2823. Independent risk factors for late alloimmunisation were blood transfusion, parity and chorionic villus sampling/amniocentesis in the current pregnancy. The occurrence of most factors before the current pregnancy suggests a secondary immune response explaining most late alloimmunisations. Tweetable abstract Third trimester screening for alloimmunisation in Rhc‐neg women improves detection and treatment of severe HDFN .