Cite this page: Ziadie MS. Fetal trisomies. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/placentatrisomy.html. Accessed September 24th, 2020.
- Trisomy 21: elevated serum hcG and inhibin, reduced serum estradiol and AFP
- Trisomy 18: low serum hcG, low AFP, low inhibin and low estradiol
- Single umbilical artery is more common in trisomic pregnancies
- Early spontaneous abortions may show no fetal parts and an absent umbilical cord (Hum Pathol 1995;26:201)
Microscopic (histologic) description
- Large hypovascular / avascular villi with irregular borders accompanied by normal appearing villi
- Villous hydrops is also seen though less than in other abnormal karyotypes