Changes in Central and Peripheral Circulation in Intrauterine Growth-Restricted Fetuses at Different Stages of Umbilical Artery Flow Deterioration: New Fetal Cardiac and Brain Parameters

Abstract

Objective: To evaluate changes in central and peripheral circulation, including new and standard parameters of the fetal brain and heart in fetuses with intrauterine growth restriction (IUGR) in relation to progressive deterioration of the umbilical artery (UA). Methods: Seventy-two IUGR fetuses were studied longitudinally. IUGR was defined as an estimated fetal weight <10th centile for gestational age. Fetuses were classified according the UA pulsatility index (PI) as: group 1, normal UA-PI (<95th centile; <1.645 z-scores), group 2, UA-PI (≧95th centile and <99th centile; ≧1.645 and <3 z-scores), group 3, UA absent end-diastolic flow, and group 4, UA reversed end-diastolic flow. Middle cerebral artery (MCA), anterior cerebral artery segments 1 (ACA1) and 2 (ACA2), aortic isthmus blood flow index (IFI), modified myocardial performance index (Mod-MPI), ductus venosus (DV), renal artery (RA), femoral artery (FA) and amniotic fluid index (AFI) were weekly evaluated until delivery. Results: A total of 263 scans were performed (median, 3 (range: 1–23) per patient). There were 6 intrauterine and 2 neonatal deaths. Although all cerebral arteries showed a reduction in the PI, ACA1 showed the earliest vasodilatation. From group 2 onwards, all cerebral vessels had a similar pattern of vasodilatation. Mod-MPI became abnormal at group 1 with no further changes. IFI and DV became constantly abnormal starting from group 2. No changes in the RA-PI or FA-PI were documented. Conclusion: The process of hemodynamic deterioration in IUGR fetuses seems to be earlier represented by the ACA1 and the Mod-MPI. Signs of further deterioration were observed in the DV, IFI and MCA. The peripheral blood in the RA and FA did not show any change. AFI showed a late deterioration process.