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Anti-D administration in pregnancy for preventing Rhesus alloimmunisationCrowther CA, Middleton P
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SummaryAnti-D administration in pregnancy for preventing Rhesus alloimmunisationAnti-D given during pregnancy at 28 and 34 weeks of pregnancy reduces incidence of antibody formation and probably also reduces immunisation of women. Women whose blood group is Rh-negative sometimes form Rh-antibodies when carrying a Rh-positive baby. This is more likely during birth, but occasionally happens in late pregnancy. It can cause anaemia, and sometimes death, for a Rh-positive baby in a subsequent pregnancy. Giving the mother anti-D after the first birth does reduce the problems, but giving anti-D during pregnancy is likely to help as well, although more research is required to confirm these possible benefits and identify possible harms.
This is a Cochrane review abstract and plain language summary, prepared and maintained by The Cochrane Collaboration, currently published in The Cochrane Database of Systematic Reviews 2009 Issue 4, Copyright © 2009 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.. The full text of the review is available in The Cochrane Library (ISSN 1464-780X).
This version first published online:
April 22. 1996 AbstractBackgroundDuring pregnancy, a Rhesus negative (Rh-negative) woman may develop antibodies when her fetus is Rhesus positive (Rh-positive). These may harm Rh-positive babies. ObjectivesTo assess the effects of antenatal anti-D immunoglobulin on the incidence of Rhesus D alloimmunisation when given to Rh-negative women without anti-D antibodies. Search strategyWe searched the Cochrane Pregnancy and Childbirth Group's Trials Register (June 2007), and bibliographies. Selection criteriaRandomised trials in Rh-negative women without anti-D antibodies given anti-D after 28 weeks of pregnancy, compared with no treatment or placebo. Data collection and analysisOne review author extracted and double-entered data; these were checked by another review author. Main resultsTwo average to poor-quality trials, involving over 4500 women, compared anti-D prophylaxis with no treatment. When women received anti-D at 28 and 34 weeks' gestation, relative risk (RR) of immunisation during pregnancy was 0.42 (95% confidence interval (CI) 0.15 to 1.17); after the birth of a Rh-positive infant the RR was 0.42 (95% CI 0.15 to 1.17); and within 12 months after birth of a Rh-positive infant the RR was 0.41 (95% CI 0.16 to 1.04). While none of these differences were statistically significant, the risk difference (RD) between anti-D and no treatment was significant (RD -0.01, 95% CI -0.01 to 0.00) suggesting reduced incidence of immunisation after anti-D prophylaxis. In the higher dose trial (100 µg; 500 international units (IU) anti-D), there was a nonsignificant reduction in immunisation at two to 12 months following birth of a Rh-positive infant in women who had received anti-D (RR 0.14, 95% CI 0.02 to 1.15). However, women receiving anti-D were significantly less likely to register a positive Kleihauer test (which detects fetal cells in maternal blood) in pregnancy (RR 0.60, 95% CI 0.41 to 0.88) and at the birth of a Rh-positive infant (RR 0.60, 95% CI 0.46 to 0.79). No data were available for the risk of Rhesus D alloimmunisation in a subsequent pregnancy. No differences were seen for neonatal jaundice. Authors' conclusionsThe risk of Rhesus D alloimmunisation during or immediately after a first pregnancy is about 1%. Administration of 100 µg (500 IU) anti-D to women in their first pregnancy can reduce this risk to about 0.2% without, to date, any adverse effects. Although unlikely to confer benefit in the current pregnancy, fewer women may have Rhesus D antibodies in any subsequent pregnancy, but the effects of this needs to be tested in studies of robust design. |