Gestational trophoblastic disease

Abnormal (nonmolar) villous lesions

Fetal trisomies

Last author update: 1 November 2011
Last staff update: 19 April 2021

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PubMed Search: Fetal trisomies placenta[title]

Mandolin S. Ziadie, M.D.
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Cite this page: Ziadie MS. Fetal trisomies. website. Accessed October 3rd, 2023.
Trisomy 13
  • Often abnormal placenta (small placental volume, reduced placental vascularization, a partial molar appearance, placental mesenchymal dysplasia) and preeclampsia (Taiwan J Obstet Gynecol 2009;48:3)
  • Also retinal dysplasia: retinal pigment epithelium within optic nerve or unilateral malformed eye not associated with other anomalies (such as persistent hyperplastic primary vitreous); histology shows series of straight branching tubes composed of abortive rod and cone layers (Arch Pathol Lab Med 1977;101:540)
  • Trisomy 21: elevated serum hcG and inhibin, reduced serum estradiol and AFP
  • Trisomy 18: low serum hcG, low AFP, low inhibin and low estradiol
Gross description
  • 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
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