Hemodynamic adaptation to suboptimal fetal growth in patients with single ventricle physiology.

ABSTRACT

BACKGROUND: In fetuses with structurally normal heart and suboptimal fetal growth (SFG), umbilical artery vascular resistance increases as measured by umbilical artery pulsatility index (UA-PI). The objective of this study is to compare hemodynamic responses to SFG in fetuses with single ventricle (SV) and controls with structurally normal heart. METHODS: Fetal echocardiograms around 30 weeks of gestation were reviewed. UA-PI and middle cerebral artery pulsatility index (MCA-PI) were calculated. SFG was defined as a birth weight below 25th percentile for gestational age. RESULTS: Studies from 92 fetuses were reviewed-SV (n = 50) and controls (n = 42). The prevalence of SFG was higher in SV compared to controls (46% vs 21%, P = .02). In patients with normal heart and SFG, UAPI was significantly higher than normal controls (P = .003) suggesting increased placental vascular resistance. In SV with SFG there was no difference in UAPI compared to SV without SFG. There was no difference in MCA-PI between the groups. CONCLUSIONS: The hemodynamic response to SFG in SV varies from fetuses with structurally normal heart. The mechanism of SFG and the placental pathology may be distinct in SV.