These maternal antibodies (directed against antigens inherited from the father) may, however cause haemolytic disease in subsequent pregnancies with Rh‐positive fetuses. Sensitisation is believed to have no adverse health effects for the mother, and the first baby is usually not harmed, as the pregnancy is generally complete by the time that sensitisation has occurred. It is believed to take between five and 15 weeks for such antibodies to appear in the maternal circulation following a sensitising event such as birth ( Gunson 1976). The production of anti‐D antibodies occurs in response to the presence of fetal red blood cells in the maternal circulation this maternal immune response towards the fetal Rhesus antigen is known as ‘sensitisation’ or immunisation. Rh‐negative mothers carrying a Rh‐positive fetus may produce anti‐D antibodies (anti‐D) following small feto‐maternal haemorrhages at birth ( Chown 1954 Chilcott 2002). Neither of the trials reported on adverse effects associated with anti‐D treatment. No clear differences were seen for neonatal jaundice (RR 0.26, 95% CI 0.03 to 2.30 1882 infants GRADE: very low quality evidence). Neither of the trials reported on incidence of Rhesus D alloimmunisation in subsequent pregnancies.Ĭonsidering secondary outcomes, in one trial, women receiving anti‐D during pregnancy were shown to be less likely to register a positive Kleihauer test (which detects fetal cells in maternal blood) in pregnancy (at 32 to 25 weeks) (RR 0.60, 95% CI 0.41 to 0.88 1884 women GRADE: low quality evidence) and at the birth of a Rh‐positive infant (RR 0.60, 95% CI 0.46 to 0.79 1189 women GRADE: low quality evidence). In regards to primary review outcomes, there did not appear to be a clear difference in the risks of immunisation when women who received anti‐D at 28 and 34 weeks' gestation were compared with women who were not given antenatal anti‐D: risk ratio (RR) for incidence of Rhesus D alloimmunisation during pregnancy was 0.42 (95% confidence interval (CI) 0.15 to 1.17, two trials, 3902 women GRADE: low quality evidence) at birth of a Rh‐positive infant the RR was 0.42 (95% CI 0.15 to 1.17, two trials, 2297 women) and within 12 months after birth of a Rh‐positive infant the average RR was 0.39 (95% CI 0.10 to 1.62, two trials, 2048 women Tau²: 0.47 I²: 39% GRADE: low quality evidence). The quality of the evidence for pre‐specified outcomes was also assessed using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach. Overall, the trials were judged to be at moderate to high risk of bias. If your baby’s RhD positive, you’ll be offered another injection of anti-D.īecause the benefits of anti-D injections go away after a few months, you may need injections if you get pregnant again.We included two trials involving over 4500 women, comparing anti‐D prophylaxis with no anti‐D during pregnancy in this review. your baby will have their blood group tested when they’re born.you’ll be offered an injection of anti-D at around week 28 of your pregnancy.This means there’s less chance your baby will be anaemic. If you have an RhD negative blood group, anti-D injections can stop these antibodies from developing. If your blood is RhD negative and your baby’s is RhD positive, anti-D antibodies can cross the placenta and attack the baby’s red blood cells.Īlthough this is very rare if it happens your baby may need treatment after delivery or even before they’re born. This is unlikely to be an issue in a first-time pregnancy but can be serious in future pregnancies. The next time you’re exposed to RhD positive blood, your body produces antibodies immediately. if you bleed in pregnancy for any reason.If you’re RhD negative, there can be issues if your baby is RhD positive and their blood enters your bloodstream. RhD negative bloodĪbout 1 in 6 women has an RhD negative blood group. If you’re Rhesus negative, this means you don’t have a substance called the Rhesus antigen on your blood cells. If you’re Rhesus positive, you don’t need treatment. The test will also show if you’re Rhesus positive or Rhesus negative. Your blood group might be the same as your baby’s, but it can be different. If these antibodies are found, your healthcare professional will discuss it with you. It’s also important because substances in the blood called blood-group antibodies can sometimes affect your baby. It’s important to know your blood group in case you or your baby need a blood transfusion. If you haven’t had a blood test to check your blood group, talk to your midwife. Having your blood group checked is an important part of your antenatal care and vital for the health of your baby.
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