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placental maturation

Friday 29 December 2006

Synopsis

- The cross-sectional surface, number, and circumference of villous vessels only increase until the 20th week.
- The relative degree of vascularization increases further until 28th week together with a continuous decrease in villous size.
- Epithelial plates start to appear in the 18th to 20th week, and their development is essentially completed by the 28th week.
- The development and differentiation of the placental villus are completed by the 28th week of gestation. Any further increase in nutritional capacity can only be provided by an increase in the number of villi and not their individual maturation.

References

- Stoz F, Schuhmann RA, Schebesta B. The development of the placental villus during normal pregnancy: morphometric data base. Arch Gynecol Obstet. 1988;244(1):23-32. PMID: 3240003