How is placental intimacy increased in Epitheliochorial placentae?

Placental intimacy may be increased by chorionic ridges that fit into corresponding uterine grooves. The epithelium covering the villi generally have microvilli that interdigitate with uterine epithelial microvilli; this further improves intimacy and increases the surface area for metabolite exchange. Intra-epithelial capillaries are present and improve placental intimacy without reducing the number of tissue layers.