Relationship between catecholamine levels in amniotic fluid and fetal blood flow in fetal distress

: Eighteen cases of complicated pregnancy with fetal distress and/or pregnancy toxemia who underwent Cesarean section (CS) before onset of labor were studied. The resistance indexes (RI) of the umbilical artery (UA) and fetal middle cerebral artery (MCA) were measured by Doppler echography prior to CS. UA blood and amniotic fluid (AF) were obtained during CS and the pH value for the UA and the concentrations of norepinephrine (NE) and epinephrine (E) in AF were measured. A significant correlation between the pH value, MCA-RI/UA-RI ratio and the levels of NE and E in amniotic fluid was obtained. NE and E concentrations in AF obtained from the patients with fetal distress before the onset of labor were 1.92 +/- 0.54 and 1.48 +/- 0.28ng/ml and these concentrations were significantly higher then those from elective CS. The deviations (delta SD) of RI from the normal mean for corresponding gestational age in fetal distress were -4.21 +/- 0.94 in MCA and 1.31 +/- 0.48 in UA. A negative correlation between the pH value and delta SD (UA) was observed but the pH value correlated positively with delta SD (MCA). Furthermore, the MCA-RI/UA-RI ratio showed a significant negative correlation with the NE and E levels in AF. These results suggest that fetal catecholamine affects fetal blood flow in fetal distress.