Effect of maternal corticosteroid provision on middle cerebral artery peak systolic velocity readings in the potentially anaemic fetus prior to planned intrauterine transfusion.

PURPOSE: Middle Cerebral Artery Peak Systolic Velocity (MCA-PSV) is the main tool for determining need for and timing of intrauterine transfusions (IUT) for severe fetal anaemia. It has been suggested that steroids temporarily decrease MCA-PSV, potentially increasing false-negative MCA-PSV findings in anaemic fetuses. We therefore aimed to assess whether maternal corticosteroid administration prior to IUT is associated with clinically significant temporary decreases in MCA-PSV.
METHODS: Retrospective review 2005-2016 of steroid provision prior to IUT, with correlation of MCA-PSV pre- and post-steroid administration and haemoglobin at IUT.
RESULTS: In 23 identified cases, there was no significant difference between average MoM pre- and post-steroid (1.71 ± 0.41 vs. 1.66 ± 0.38, -2.9% mean, P = 0.4). There was also no significant difference between pre- and post-steroid MoM taken within 3 days of each other (n = 19, P = 0.21). However, post-steroid MCA-PSV decreased by >15% in 6/23 cases (A-B zone in two cases, B-C zone in one case).
CONCLUSIONS: This study found no sizeable, generalised effect of corticosteroid administration on MCA-PSV readings in the potentially anaemic fetus. A minority showed substantial shifts where reliance on post-steroid MCA-PSV could have unfavourably altered clinical management. Ultimately, further large-scale research is required before we can discount the potential impact of steroids on MCA-PSV values.