Performance of fetal middle cerebral artery peak systolic velocity for prediction of anemia in untransfused and transfused fetuses: systematic review and meta-analysis

Objective To evaluate the performance of fetal middle cerebral artery peak systolic velocity (MCA-PSV) >= 1.5 multiples of the median (MoM) for the prediction of moderate-severe anemia, in untransfused and transfused fetuses. Methods A systematic search was performed to identify relevant observational studies reported in the period 2008-2018 that evaluated the performance of MCA-PSV, using a threshold of 1.5 MoM for the prediction of fetal anemia. Diagnosis of fetal anemia by blood sampling was the reference standard. A hierarchical summary receiver-operating characteristics (hSROC) curve was constructed using random-effects modeling. Subgroup and meta-regression analyses, according to the number of previous intrauterine transfusions, were performed. Results Twelve studies and 696 fetuses were included in the meta-analysis. The area under the hSROC curve (AUC) for moderate-severe anemia was 83%. Pooled sensitivity and specificity (95% CI) were 79% (70-86%) and 73% (62-82%), respectively, and positive and negative likelihood ratios were 2.94 (95% CI, 2.13-4.00) and 0.272 (95% CI, 0.188-0.371). When considering only untransfused fetuses, prediction improved, achieving an AUC of 87%, sensitivity of 86% (95% CI, 75-93%) and specificity of 71% (95% CI, 49-87%). A decline in sensitivity for the prediction of moderate-severe anemia by MCA-PSV >= 1.5 MoM was observed (estimate, -5.5% (95% CI, -10.7 to -0.3%), P = 0.039) as the number of previous transfusions increased. Conclusions MCA-PSV >= 1.5 MoM for the prediction of moderate-severe anemia in untransfused fetuses shows moderate accuracy (86% sensitivity and 71% specificity), which declines with increasing number of intrauterine transfusions. Copyright (C) 2019 ISUOG. Published by John Wiley & Sons Ltd.