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Introduction: The aim of this study was to assess the accuracy of the non-invasive fetal RHD test at 24-26 weeks of gestation as part of the national antenatal screening program to target routine antenatal anti-D prophylaxis (RAADP) at 28-30 weeks at women carrying an RhD-positive fetus., Material and Methods: A prospective cohort study involving all maternity care centers and delivery hospitals in Finland between February 2014 and January 2016. Fetal RHD genotyping using cell-free fetal DNA in maternal plasma was performed with real-time polymerase chain reaction in a centralized setting. The results were systematically compared with the serological newborn RhD typing. The main outcome measure was the accuracy of the fetal RHD assay; the secondary variable was compliance with the newly introduced RAADP program., Results: Fetal RHD was screened from 10 814 women. For the detection of fetal RHD, sensitivity was 99.99% [95% confidence interval (CI) 99.92-99.99] and specificity 99.81% (95% CI 99.60-99.92). One false-negative and seven false-positive results were reported by the delivery hospitals in two years. The negative predictive value of the test was 99.97% (95% CI 99.81-99.99). At the end of the study period, over 98% of the RhD-negative women participated in the new screening program., Conclusions: The targeted RAAPD program was implemented effectively in the national maternity care program in Finland. An accurate fetal RHD screening test allows discontinuation of newborn testing without risking the postnatal prophylaxis program. In the future, the main area to investigate will be the clinical effect of RAADP on subsequent pregnancies., (© 2017 Nordic Federation of Societies of Obstetrics and Gynecology.)

Objective: We present a pharmacokinetic study evaluating a single intramuscular dose of 250 μg anti-D immunoglobulin in the third trimester of pregnancy. The aim of the study was to determine the kinetic profile and duration of detectable levels of anti-D., Design: Prospective observational study., Setting: Antenatal outpatient clinic., Population: Healthy Rhesus D (RhD)-negative pregnant women with an RHD-positive fetus., Methods: Serial plasma anti-D quantitations following antenatal administration of anti-D immunoglobulin were performed using flow cytometry. Kinetic profiles for anti-D levels were generated from the concentration values at predetermined sampling time points. The half-lives were calculated by linear regression analysis. Main outcome measures. Time vs. concentration profile, half-life and anti-D concentration ≥1 ng/mL close to term., Results: The maximal plasma concentration of anti-D was usually seen at 3-10 days postinjection, with a median value of 25 ng/mL. The half-life varied between individuals, with a median of 23 days. We found detectable levels of anti-D IgG within two weeks of parturition in 11 of 12 women., Conclusions: The preparation of anti-D immunoglobulin used in the present study, if administrated in pregnancy week 28-30, is associated with detectable levels of anti-D in most women at the time of delivery. Although the half-time is 23 days, it is uncertain whether all mothers have adequate anti-D concentrations at term. Alternative strategies may be evaluated in the future, with repeated administration of antenatal prophylaxis at term rather than conventional postpartum administration of anti-D., (© 2012 The Authors Acta Obstetricia et Gynecologica Scandinavica© 2012 Nordic Federation of Societies of Obstetrics and Gynecology.)