Fetal blood sampling: is intrahepatic vein fetal blood sampling as successful as percutaneous umbilical cord blood sampling?

Abstract

SAMPLING AS SUCCESSFUL AS PERCUTANEOUS UMBILICAL CORD BLOOD SAMPLING? CYNTHIA HOLCROFT, ABIMBOLA AINA-MUMUNEY, RITA DRIGGERS, NANCY HUEPPCHEN, EVA PRESSMAN, KARIN BLAKEMORE, Johns Hopkins University, Gynecology & Obstetrics, Baltimore, MD OBJECTIVE: To determine the success rate and variables that alter success in intrahepatic vein fetal blood sampling (IHV) and percutaneous umbilical cord blood sampling (PUBS). STUDY DESIGN: IRB-approved retrospective chart review of attempted fetal blood samplings done at our institution by IHV or PUBS from 7/87-8/03. Data abstracted include gestational age at procedure, placental location, presence of hydrops or ascites, attempted procedure, and success of procedure. Data analyzed by t-test, Fisher’s exact, and chi-square with P < 0.05 considered significant. RESULTS: We identified 187 attempted cases: 97 IHV, 75 PUBS, and 15 combined procedures. 96 of 112 (86%) of attempted IHV were successful vs 70 of 90 (78%) of attempted PUBS (P = 0.14). In 5 of 96 (5%) successful IHV cases, PUBS was first tried unsuccessfully; in 8 of 70 (11%) successful PUBS cases, IHV was first tried unsuccessfully (P = 0.16). Placental location was statistically different in the successful samplings. For successful IHV, placental location was anterior 47%, posterior 43%, and fundal/lateral 10%. For successful PUBS, placental location was anterior 67%, posterior 21%, and fundal/lateral 12% (P = 0.01). There were 27 of 187 (14%) attempted cases performed at #22 weeks’ gestation; of these, 8 of 9 (89%) of IHV were successful vs 15 of 18 (83%) of PUBS (P = 1.0). There was no statistical difference in gestational age, hydrops, or ascites between either attempted or successful IHV and PUBS. CONCLUSION: IHV is as successful as PUBS in obtaining an adequate fetal blood sample. In our series IHV was slightly more successful than PUBS, although this difference did not reach statistical significance (86% vs 78%, P = 0.14). Gestational age did not contribute to a difference in success rate. For successful procedures the placenta was posterior in 43% of IHV versus 21% of PUBS. IHV should be considered a strong alternative to PUBS for fetal blood sampling, particularly in cases with posterior placentas.