Detectability of Anti-D and Compliance in Two Regimens

INTERVENTION: Rh(D) Immunoglobulin‐VF is a sterile, preservative‐free solution containing human plasma proteins and 22.5 mg/mL glycine. The solution has a pH of 6.6. At least 98% of the protein is immunoglobulin (mainly IgG), with an anti‐D (Rho) antibody content of 625 IU per vial/ =30 mg/mL human plasma proteins or 250 IU per vial/ =10 mg/mL human plasma proteins.Rh(D) Immunoglobulin‐VF (Anti‐D) is a human immunoglobulin preparation for intramuscular administration. Rh(D) Immunoglobulin‐VF is prepared from blood obtained from voluntary and non‐remunerated (unpaid) donors. Rh(D) Immunoglobulin‐VF contains proteins called antibodies which help to suppress the unwanted immune response in an Rh(D) negative woman following her exposure to Rh(D) positive red cells. For example, if a pregnant woman has an Rh(D) negative blood group and her baby is Rh(D) positive, the baby's blood is incompatible with the mother’s. This could lead to reduced red blood cells, brain damage and other serious complications in the baby. This condition is known as Haemolytic Disease of the Newborn. Rh(D) Immunoglobulin‐VF can be given to Rh(D) negative women during pregnancy and following birth of an Rh(D) positive baby to help prevent Haemolytic Disease of the Newborn. Rh(D) Immunoglobulin‐VF is sometimes given on other occasions when a woman of child‐bearing age may become exposed to Rh(D) positive blood: for example, after blood transfusion, amniocentesis (taking a sample of the fluid surrounding the unborn baby), miscarriage or stillbirth. Rh(D) Immunoglobulin‐VF is available only with a doctor’s prescription. Route for both control and intervention: Intra‐muscular injection of Rh(D) Immunoglobulin‐VF, produced by the Commonwealth Serum Laboratories (CSL), as per current practice Control group: 625 IU Rh(D) Immunoglobulin‐VF at 28 and 34 weeks gestation as per current KEMH practice. Intervention group: 1500 IU Rh(D) Immunoglobulin‐VF at 28 weeks gestation as approved in clinical guidelines for a single‐dose regime. CONDITION: Pregnancy Rhesus negative blood type Sensitisation to the D‐Antigen PRIMARY OUTCOME: Detectability of anti‐D at delivery via standard diagnostic practices employed at King Edward Memorial Hospital Proportion of women receiving doses at correct gestation via analysis of number of enrolments compared with the number and timing of doses delivered in each arm of the study. SECONDARY OUTCOME: Complication rates (obstetric and neonatal) via review of medical records. Risk factors for no detectable antibody at delivery via questionnaire and review of medical records The total amount of anti‐D used per participant: ; The total amount of anti‐D used per participant will be calculated by summing the amount of anti‐D administered (International Units) during the trial period. ; ; i.e. Participant in single dose arm 1500 = 1500 IU ; Participant in two dose arm 625 + 625 =1250 IU ; Non‐compliant two dose participant 650 + 0 = 650IU ; INCLUSION CRITERIA: Female, pregnant, aged over 18 years, with a negative antibody screen and no contraindications for anti‐D intramuscular injection, such as previous anaphylaxis to immunoglobulin, isolated Immunoglobulin A (IgA) deficiency, or previously recorded endogenous anti‐D antibodies