OBJECTIVE: To determine whether sonographic assessments of increasing placental maturity are associated with changes in the theoretical diffusing capacity of the organ and with changes in vascular resistance. DESIGN: Placental maturity was assessed sonographically in 10 organs: five were classified as completely immature and five as completely mature. Doppler flow velocimetric recordings were obtained shortly before delivery performed by elective caesarean section. Placental biopsies taken immediately after delivery were analysed stereologically. RESULTS: No differences were observed in either placental weight or volume, but the morphometric diffusing capacity of the villous membrane was 40% higher in the mature than in the immature placentas. Doppler indices did not alter with increasing placental maturity. CONCLUSIONS: Normal term placentas differ significantly in their diffusion characteristics, even when organ weight and volume remain constant. Umbilical vascular resistance may be heavily influenced by the number of parallel circulatory units offered by the placental lobules.
OBJECTIVE: To determine whether sonographic assessments of increasing placental maturity are associated with changes in the theoretical diffusing capacity of the organ and with changes in vascular resistance. DESIGN: Placental maturity was assessed sonographically in 10 organs: five were classified as completely immature and five as completely mature. Doppler flow velocimetric recordings were obtained shortly before delivery performed by elective caesarean section. Placental biopsies taken immediately after delivery were analysed stereologically. RESULTS: No differences were observed in either placental weight or volume, but the morphometric diffusing capacity of the villous membrane was 40% higher in the mature than in the immature placentas. Doppler indices did not alter with increasing placental maturity. CONCLUSIONS: Normal term placentas differ significantly in their diffusion characteristics, even when organ weight and volume remain constant. Umbilical vascular resistance may be heavily influenced by the number of parallel circulatory units offered by the placental lobules.
Authors: André Dallmann; Ibrahim Ince; Michaela Meyer; Stefan Willmann; Thomas Eissing; Georg Hempel Journal: Clin Pharmacokinet Date: 2017-11 Impact factor: 6.447
Authors: Laura A Cox; Cun Li; Jeremy P Glenn; Kenneth Lange; Kimberly D Spradling; Peter W Nathanielsz; Thomas Jansson Journal: J Nutr Date: 2013-09-18 Impact factor: 4.798