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Background: Haemolytic disease of the fetus/newborn secondary to clinically significant non-Rhesus-D antibodies has risen in importance since the advent of immunoprophylactic anti-D administration to Rhesus-D negative women. Of interest is the incidence of these antibodies in Rhesus-D positive women, who receive less frequent antenatal alloantibody screening. This is of particular concern if the antibodies arise late in pregnancy and may go undetected., Aims: To assess the proportion of Rhesus-D positive pregnant women with late developing clinically significant antibodies for haemolytic disease of the fetus/newborn, and whether these resulted in adverse fetal outcomes., Materials and Methods: A retrospective analysis over a 12-month period at a tertiary hospital in the Northern Territory. Group and antibody screen results in addition to clinical data regarding pregnancy/newborn were collected., Results: Sixty-four of 2612 women (2.5%) had red blood cell antibodies detected during their pregnancy. Of these, 21 clinically significant antibodies were detected in 19 women (0.7% of initial cohort). The most common antibody detected was anti-c (28.5%). In six of these women (0.23% of initial cohort), the antibodies were late developing. Mild jaundice was noted in three newborns with phototherapy required in one., Conclusions: Although clinically significant antibodies were detected during pregnancy, and in a small proportion of cases as a late developing antibody undetected in the first trimester screening, clinical outcomes for the newborn were mild. As such, the cost of retesting all Rhesus-D positive pregnant women in the third trimester would be considerable and unlikely to result in any meaningful clinical benefit., (© 2017 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)

Objective: To assess the pharmacokinetics of anti-D IgG in pregnant Rhesus D-negative women after intramuscular and intravenous administration of 300 microg of Rhophylac., Design: An open, randomised, multicentre study., Setting: Seven gynaecological practices in Germany., Sample: Fourteen RhD-negative pregnant women at risk of becoming Rhesus D immunised received study drug at 28th week of pregnancy either by intramuscular or intravenous route., Main Outcome Measures: Anti-D IgG concentrations of serum samples obtained up to 11 weeks following antenatal Rhesus D prophylaxis were quantified by flow cytometry., Results: Mean anti-D IgG concentrations after intravenous and intramuscular administration differed up to seven days post-injection, from two weeks onwards they were comparable to each other. Irrespective of the administration route, anti-D IgG in serum was detectable in all women up to at least nine weeks post-administration., Conclusions: The serum concentrations of anti-D IgG measured after administration of Rhophylac were very similar to those obtained with 300 microg of a different anti-D immunoglobulin product.

Fetal RHD genotype determination is useful in the management of sensitized RhD-negative pregnant women. It can be ascertained early during pregnancy by chorionic villus sampling (CVS) or amniocentesis. However, these procedures are invasive, resulting both in an increased risk of fetal loss and in an increased severity of immunization due to fetomaternal haemorrhage. A reliable determination of RHD genotype by fetal DNA analysis in maternal serum during the first trimester of pregnancy is reported in this study. One hundred and six sera from RhD-negative pregnant women were obtained during the first trimester of pregnancy. These sera were tested for the presence of RHD gene using a new real-time polymerase chain reaction assay and the results compared with those obtained later in pregnancy on amniotic fluid cells and by RHD serology of the new-born. All sera from women carrying a RhD-positive fetus (n = 62) gave positive results for RHD gene detection and sera from women carrying a RhD-negative fetus (n = 40) were negative. The high level of accuracy of fetal RHD genotyping obtained in this study could enable this technique to be offered on a routine basis for the management of RhD-negative patients during the first trimester of pregnancy.

The ability of the chemiluminescence test (CLT) to predict the severity of haemolytic disease of the newborn (HDN) was determined in 80 alloimmunized pregnant women who delivered antigen-positive babies. In 54 cases of alloimmunization to D, results from the CLT showed better correlation with fetal outcome than anti-D concentration measured by AutoAnalyzer (r = 0.70 and 0.36 respectively). Results from the CLT permitted a threshold level of antibody activity (30%) below which 15/20 babies were unaffected or had mild disease, and only one required transfusion therapy in utero. CLT results above 30% were associated with moderate or severe disease in all cases. Results from the AutoAnalyzer proved a less reliable predictor of disease severity; three women with anti-D levels > 20 iu/ml delivered unaffected babies, and two women with anti-D levels < 10 iu/ml delivered babies who had required transfusion in utero. The clinical usefulness of the CLT derives from the possibility of avoiding invasive monitoring procedures in women with high levels of anti-D which is relatively non-functional.