Anti-D administration after childbirth for preventing Rhesus alloimmunisation.

BACKGROUND

The development of Rh immunisation and its prophylactic use since the 1970s has meant that severe Rhesus D (RhD) alloimmunisation is now rarely seen.

OBJECTIVES

The objective of this systematic review was to assess the effects of giving anti-D to Rhesus negative women, with no anti-D antibodies, who had given birth to a Rhesus positive infant.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled Trials Register, MEDLINE (from 1966 to January 1999) and reference lists of relevant articles. Date of last search of Cochrane Controlled Trials Register: January 1999.

SELECTION CRITERIA

Randomised trials in Rhesus negative women without antibodies who were given anti-D immunoglobulin postpartum compared with no treatment or placebo.

DATA COLLECTION AND ANALYSIS

Assessments of inclusion criteria, trial quality and data extraction were done by each author independently. Initial analyses included all trials. Other analyses assessed the effect of trial quality, ABO compatibility and dose.

MAIN RESULTS

Six eligible trials compared postpartum anti-D prophylaxis with no treatment or placebo. The trials involved over 10,000 women, but trial quality varied. Anti-D lowered the incidence of RhD alloimmunisation six months after birth (relative risk 0.04, 95% confidence interval 0.02 to 0.06), and in a subsequent pregnancy (relative risk 0.12, 95% confidence interval 0. 07 to 0.23). These benefits were seen regardless of the ABO status of the mother and baby and when anti-D was given within 72 hours of birth. Higher doses (up to 200 micro grams) were more effective than lower doses (up to 50 micro grams) in preventing RhD alloimmunisation in a subsequent pregnancy.

REVIEWER'S CONCLUSIONS: Anti-D, given within 72 hours after childbirth, reduces the risk of RhD alloimmunisation in Rhesus negative women who have given birth to a Rhesus positive infant. However the evidence on the optimal dose is limited.