Objective To observe the pharmacokinetics of intramuscular anti-D immunoglobulin (IgG) given for routine antenatal prophylaxis.Design Prospective observational study.Setting Maternity unit and antenatal serology laboratory in a district teaching hospital.Population Forty-five rhesus-D-negative pregnant women not sensitised to RhD. Results For the 43 women in whom serial data were collected, there were no detectable differences between pregnancies with an RhD-positive (26) or -negative (17) fetus. Maximum IgG concentrations were detected two to five days following the first anti-D IgG injection and ranged between 0 and 28 ng/mL. Only 30% of women still undelivered at 40 weeks of gestation had detectable IgG at 2 ng/mL or greater. There was a significant relationship between higher maximum values and low maternal surface body area (R 2 = 0.204, P = 0.002), but this did not influence duration of persistent IgG.Conclusion Using previously published data, 70% women are not adequately protected with anti-D IgG 12 weeks after the first prophylactic injection. Despite this, previous clinical results suggest that the antenatal prophylaxis schedule used provides adequate protection and that the recommendation for the lowest concentration of protective anti-D IgG antibody levels currently in use is probably overestimated.Please cite this paper as: MacKenzie I, Roseman F, Findlay J, Thompson K, Jackson E, Scott J, Reed M. The Kinetics of routine antenatal prophylactic intramuscular injections of polyclonal anti-D immunoglobulin.
Documented routine antenatal anti-D prophylaxis was given to 90% and 81-87% of eligible women at 28 and 34 weeks of gestation, respectively, during the early 1990s and early 2000s. With increasing experience and education, a significant improvement in the timing of the first (OR 0.26, 95% CI 0.16-0.41: P < 0.0001) and second injections (OR 0.40, 95% CI 0.26-0.61: P < 0.0001) occurred during the latter period. Despite these improvements, there was no reduction in the sensitisation rate at 0.4%. However, this low rate occurred despite significant proportions of women delivering more than 42 days after the second injection. Fifteen of the 16 sensitised women had received routine antenatal prophylaxis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.