(1028) The association between PSV MCA and perinatal outcomes in pregnancies complicated by small-for-gestational-age/fetal-growth-restricted fetuses

Objective: This study aimed to determine the relationship between middle cerebral artery (MCA) peak systolic velocity (PSV) and perinatal morbidity and mortality in SGA and FGR fetuses.

Study Design: A retrospective cohort study from a tertiary hospital including all singleton pregnancies without fetal genetic/structural anomalies and EFW and/or AC < 10^th centile for gestational age (2017-2022). Only cases in which the umbilical artery (UA) and MCA were concurrently sampled within 14 days of birth were considered. The study compared cases with abnormal MCA PSV ( > 95th centile for gestational age) to pregnancies with normal MCA PSV. The primary outcome was a composite adverse perinatal outcomes defined as either antenatal fetal death, cesarean birth due to fetal distress, 5-minute Apgar < 7, arterial cord < 7.1, prolonged NICU admission ( >7 days), need for intubation, sepsis, necrotizing enterocolitis, and neonatal death. Multi variable logistic regressions were conducted, adjusting for relevant covariates.

Results: The study included 983 patients, among whom 98 (10%) had abnormal MCA PSV and 885 (90%) had a normal PSV MCA. Maternal sociodemographic characteristics were similar between the group. Cases with abnormal MCA PSV presented worse Doppler studies. Cases with abnormal MCA PSV delivered earlier than those with normal MCA PSV (33.9±4.5 vs. 36.1±3.3 wks; p< 0.001); nevertheless, the composite adverse perinatal outcomes did not differ between those with abnormal and normal PSV MCA (56.1% vs. 46.8%, p=0.09). Subgroup analysis limited to cases with ultrasound assessment ≥ 32 weeks (n=796); or those with normal MCA PI (≥ 5^th centile; n=708); or with normal CPR (≥ 5^th centile; n=621) presented similar composite adverse outcomes irrespective of MCA PSV status (Figure). Multivariate logistic regression controlling for MCA PI and UA PI failed to show a significant association between abnormal MCA PSV to the composite adverse outcome aOR 1.07; 95% CI 0.68-1.67.

Conclusion: In pregnancies complicated with SGA or FGR, abnormal MCA PSV, as a sole parameter, is not associated with adverse fetal/neonatal outcomes.