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Rapid Responses: Rapid Responses published:
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Is Lileys charting obsolete?
- Umber Agarwal (27 May 2005)
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RE: Management Of Pregnancies With RhD Alloimmunisation
- Edeghonghon Olayemi (28 May 2005)
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Cost-effectiveness of management strategies for pregnancies at risk of RhD alloimmunisation
- Ala Szczepura, Leeza Osipenko, and Karoline Freeman (8 June 2005)
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Umber Agarwal, Specialist Registrar Department of Obstetrics & Gynaecology, Peteborough Maternity Unit, Peterborough , PE3 5DA
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Dear Sir, I read your article with great interest.In light of the recent developments in middle cerebral doppler artery for predicting fetal anaemia, it would be interesting to know how earlier in gestation are dopplers reliable so as to commence intrauterine fetal transfusions and is spectrophotometric analysis of amniotic fluid totally obsolete with this regard? Article mentions spacing repeated transfusions at 3-5 weekly intervals.In my personel experience of assisting management of cases of severe fetal iso-immunization by serial intravascular fetal transfusion at a tertiary referral institute back in India, we used to calculate the attrition rate follwing first and subsequent transfusions which roughly was 2% and 1% respectvely.This led to the second transfusion usually with in 2-3 days after the first one and gradually the interval between subsequent transfusions was increased to about two to three weeks.Also the volume of blood transfused at each subsequent transfusion was gradually increased( starting at 30ml packed cells/ kg of estimated fetal weight and going up to 60ml/kg in later transfusions) so as to give time to fetus for the physiological adaptation to volume overload in face of a pre existing hyperdynamic circulation secondary to anaemia. Calculation of pre and post transfusion hematocrit and plotting the transfusogram helped in planning the next transfusion with final aim being to achieve a fetal hematocrit of 55-60% shortly before delivery, which usually is desirable around 37-38 weeks. Competing interests: None declared |
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Edeghonghon Olayemi, Lecturer Department of Haematology and Blood Transfusion, O.O.U. P.M.B. 2022, Sagamu, Ogun State,Nigeria
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Email:yemiede@yahoo.com I read your very interesting and well written review with a lot of sadness since it appears that once again patients in developing countries have been left out. RhD alloimmunisation is still a very common problem in Nigeria and it is very difficult to calculate the prevalence since a large proportion of pregnancies are not supervised by trained health workers. As a result of the twin evil of poverty and ignorance, a lot of patients present very late when very little can be done to salvage the fetus. Again most of the procedures you reviewed are not available and where available (e.g Doppler ultrasonography) they are carried out in very few centres in the large cities and are quite expensive. Competing interests: None declared |
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Ala Szczepura, Professor of Health Services Research Warwick Medical School, University of Warwick, CV4 7AL, UK, Leeza Osipenko, and Karoline Freeman
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Dear Sir Kumar and Regan in their review eloquently summarise the current situation in the UK as regards clinical management of pregnancies at risk of RhD alloimmunisation. This includes routine antenatal prophylaxis with anti-D immunoglobulin for all women who are RhD negative, which is now recognised as a cost-effective strategy as opposed to previous conventional management, i.e. administration of anti-D to women after the birth of an RhD positive infant and after sensitising events in pregnancy [1]. But, as further research evidence becomes available, the most cost- effective means of managing such pregnancies will once again become an issue of debate. For example, the authors quote current recommendations from the Royal College of Obstetricians and Gynaecologists and NICE for administration of two doses of anti-D immunoglobulin at 28 and 34 weeks of pregnancy. However, according to recent research [2], and practice in other countries (USA, Germany and Switzerland), it appears that immunoprophylaxis can be given safely with just one dose of anti-D immunoglobulin (~300mg) between 28 and 30 weeks. The introduction of such a regime would be cost- effective, resulting in annual savings of up to £3 million in the UK if it were to replace two dose prophylaxis. Furthermore, reduction of anti-D immunoglobulin production would help save donor blood which could be used for other products. The possibility of alternative (monoclonal antibodies) production of anti-D is not considered feasible in the next few years. More interestingly, the authors mention the emerging use of non- invasive tests based on fetal DNA in maternal blood to establish fetal Rh genotype. Their discussion is limited to management of cases of proven RhD alloimmunisation where use of such tests, in conjunction with velocimetry, has already superseded serial amniocentesis for monitoring affected pregnancies. However, with automation and potential centralisation of testing, these non-invasive tests will become less expensive and their use as screening tests for all women who are RhD negative may prove to be more cost-effective than anti-D prophylaxis administered to these same women. 100% sensitivity rates have been reported for these tests by a number of European centres [3,4,5], and screening can save anti-D immunoglobulin costs for those pregnancies found not to be at risk (ca 40% of RhD negative pregnant women). As part of the work of the SAFE Network of Excellence, recently funded by the EC (www.safenoe.org), we are currently investigating the likely socio-economic consequences of the introduction of a range of non- invasive prenatal tests based on fetal DNA and fetal cells in maternal blood. In addition to tests to establish fetal RhD status, the use of new tests for detection of haemoglobinopathies, cystic fibrosis and chromosomal abnormalities in the fetus, and for prediction of pre-term labour and preeclampsia will be assessed. 1. Chilcott J., et. al. The economics of routine antenatal anti-D prophylaxis for pregnant women who are Rh negative 2004 BJOG 111:903-907. 2. MacKenzie, IZ et al. Efficacy and safety of a new, chromatographically purified rhesus (D) immunoglobulin Eur J Obstet Gynecol Reprod Biol. 2004 1;117(2):154-61. 3. Costa, J-M, et al Genetic analysis of the fetus using maternal blood. Gynecol Obstet Fertil 32(7-8)L646- 50. 4. Hromadnikova, et. al. Non-invasive Fetal RhD and RhCE Genotying using real-time PCR testing of maternal plasma in RhD negative pregnancies. Journal of Histochemistry and Cytochemistry 53(3): 301-5. 5. van der Schoot, et. al Prenatal typing of Rh and Kell blood group system antigentL the edge of a watershed. Transfus Med Rev 17: 31-44. Competing interests: None declared |
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