RELEASE OF VASOACTIVE AGENTS DURING CORDOCENTESIS - DIFFERENCES BETWEEN NORMALLY GROWN AND GROWTH-RESTRICTED FETUSES

OBJECTIVE: The purpose of this study was to evaluate whether cordocent esis is associated with the release of vasoactive substances and wheth er there are differences between normally grown and growth-restricted fetuses. STUDY DESIGN: B-Keto-prostaglandin F-1 proportional to (the s table metabolite of prostacyclin), endothelin-1, and cyclic guanosine monophosphate were measured in fetal blood at the beginning and closin g of cordocentesis in 30 normally grown fetuses and 25 growth-restrict ed fetuses. This latter group was characterized by abnormal Doppler in dex values in umbilical artery and middle cerebral artery, suggestive of chronic hypoxemia as the causative factor of the impaired growth. I n six growth-restricted fetuses bradycardia occurred at the end of the procedure. Umbilical artery pulsatility index was measured by Doppler ultrasonography immediately before and after the procedure. RESULTS: The median interval between the two blood samples obtained by cordocen tesis was 90 seconds (range 60 to 320 seconds). During this interval a significant rise of 6-keto-prostaglandin F-1 proportional to (P less than or equal to 0.0001) and endothelin-1 (p = 0.03) was evidenced in normally grown fetuses. The increase in 6-keto-prostaglandin F-1 alpha was significantly related (r = 0.52, p = 0.002) to the fall or umbili cal artery pulsatility index occurring after the procedure. In growth- restricted fetuses cordocentesis induced a marked increase of endothel in-1 (p = 0.0002), which was significantly related to the severity of acidosis (r = 0.52, p = 0.018), whereas no modifications were evidence d for the other agents tested. The increase of endothelin-1 was higher in those growth-restricted fetuses showing bradycardia at the end of the procedure than in growth-restricted fetuses that did not (p = 0.04 ). The variations of the vasoactive substances assayed were not signif icantly related to the type of procedure (transamniotic or transplacen tal), the amount of blood aspirated during the procedure, the interval elapsing between the first and second samples, the gestational age at which the procedure was performed, and the degree of fetal smallness. CONCLUSION: Cordocentesis induces the rapid release of vasoactive sub stances and the effect differs between normally grown and growth-restr icted fetuses. This may explain the different hemodynamic response and the higher rate of complications occurring in the latter group after cardocentesis. (Am J Obstet Gynecol 1996;175:563-70.)