OP10.04: Adverse outcomes in monochorionic twins with elevated MCA Dopplers without twin‐anemia polycythemia sequence

Screening monochorionic/diamniotic (MCDA) twins for twin-anemia-polycythemia sequence (TAPS) is performed with middle cerebral artery (MCA) Dopplers. This study described the natural history of elevated MCA PSV not meeting criteria for TAPS. This case-control study reviewed MCDA twin pairs undergoing TAPS screening between 2018–2022 at a tertiary care centre. Twins with Twin–twin transfusion (TTTS), selective fetal growth restriction (sFGR), and overt TAPS were excluded, as were higher order multiples, fetal anomalies affecting Dopplers, and twins with only 1 scan available. Cases had at least 1 ultrasound documented an MCA PSV ≥ 1.5 multiples of the median (MoM). Twins with normal imaging comprised a control group. Of 737 twins, 396 were excluded for another complication of monochorionicity such as TTTS. 19 were excluded for anomalies, 10 for higher order multiples, and 44 for only 1 scan. Of the remaining 268, 224 were normal controls and 44 cases had at least 1 MCA PSV ≥ 1.5 MoM. Cases developed TAPS and TTTS at below-population rates (2/44, 5% and 3/44, 7% respectively), although these rates were different from controls by design (p = 0.026, 0.004). Gestational age at delivery and neonatal and maternal admissions were similar. Elevated MCA PSVs not meeting criteria for TAPS do not change outcomes in the absence of TTTS or sFGR. Providers should recall the risk of TTTS or TAPS and the need for close surveillance, but families can be reassured that the risks of these are low. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.