Histologic Changes in Placentas with Gross Umbilical Cord Abnormalities Correlate with Adverse Perinatal Outcome
P Tantbirojn, A Saleemuddin, K Sirois, CP Crum, TK Boyd, S Tworoger, MM Parast. Chulalongkorn University, Bangkok, Thailand; Brigham and Women's Hospital, Boston, MA; University of California San Diego, La Jolla, CA
Background: Gross umbilical cord abnormalities predisposing to fetal blood flow restriction have previously been associated with adverse perinatal outcomes; however, their common occurrence in uncomplicated births raises questions regarding their true clinical significance. Using previously established histologic parameters for stillbirth-associated compromise of umbilical blood flow, we set out to evaluate a wide range of gross cord abnormalities and their associated perinatal outcome.
Design: This was a retrospective case-control study, with 297 placentas with grossly abnormal cords and 383 gestational age-matched controls randomly selected from the pathology database. The gross cord abnormalities included excessively long cord, nuchal cord, true knot, and abnormal insertion. Placental slides from each case were reviewed by two pathologists, blinded to the clinical and gross findings. The presence of stasis-associated changes in the placental fetal vasculature, including 1) vascular ectasia, 2) thrombosis, and 3) fetal thrombotic vasculopathy (defined by avascular villi or villi with stromal karyorrhexis), was documented. Results were tabulated along with perinatal outcome data from patients' charts.
Results: Of the cases with single cord abnormalities, nuchal cords and long cords showed 1.5-5 fold higher rates of all stasis-induced histologic changes in the placenta; they also showed 3-8 fold higher rates of adverse perinatal outcome, including stillbirth and growth restriction (IUGR). Cases with multiple cord abnormalities showed 1.5-3 fold higher rates of stasis-induced ectasia and thrombosis, as well as 2-fold increased rate of IUGR. Compared to abnormal cord cases without thrombosis, the odds ratio for adverse outcome in abnormal cord cases with thrombosis was 2.90 (1.36-6.17, 95% confidence interval).
Conclusions: We conclude that stasis-induced changes in the placental fetal vasculature pinpoint the subgroup of gross cord abnormalities associated with adverse perinatal outcome. This study further demonstrates the importance of placental histologic examination, particularly in the setting of poor clinical outcome. Based on this study, we recommend proper sampling of chorionic plate vessels and placental parenchyma in order to identify these histologic changes in the placenta.
Monday, March 9, 2009 1:00 PM
Poster Session II # 204, Monday Afternoon