Placental findings in specific newborn/fetal or maternal conditions
Spontaneous abortion

Topic Completed: 1 November 2011

Minor changes: 19 February 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Spontaneous abortion[title] placenta

Mandolin S. Ziadie, M.D.
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Cite this page: Ziadie MS. Spontaneous abortion. website. Accessed August 14th, 2020.
Definition / general
  • Naturally occurring intrauterine loss is observed in 10 - 15% of clinically recognized pregnancies and 22% of pregnancies detected via hCG levels
  • May be due to fetal factors (e.g. genetic abnormalities) or maternal factors (e.g. anatomic, infectious or autoimmune)
  • Fetal loss with normal karyotype is associated with maternal age < 20 years, chronic intervillositis, increased perivillous fibrin deposition with intermediate trophoblast and decidual plasma cells (Hum Pathol 1999;30:93)
  • Fetal loss with abnormal karyotype is associated with developmental stage < 6 weeks, hydropic villi > 1 mm and villi with 2+ dysmorphic features
  • D&C to remove residual trophoblastic tissue to confirm intrauterine pregnancy and rule out gestational trophoblastic disease
  • To diagnose intrauterine pregnancy with certainty, should see fetal parts, villi and trophoblasts in sections of intrauterine contents
  • Enlarged hyalinized spiral arteries and fibrinoid matrix are suggestive
  • Decidual reaction, gestational hyperplasia (glandular secretion, stromal edema) and Arias-Stella reaction are suggestive of pregnancy (not necessarily intrauterine) but are nonspecific (also occur with hormones)
Gross description
  • Soft hemorrhagic mass of spongy tissue (villi) and soft tissue (decidua) that may be attached to membranes as an intact or ruptured gestational sac
  • Report should indicate presence of sac, state of rupture and presence of umbilical cord
  • Fetal parts should be documented and closely examined for anomalies
  • Cytogenetics should be obtained in cases of recurrent spontaneous abortion or malformed fetuses
Microscopic (histologic) description
  • Early abortions show decidual necrosis and decidual blood vessel thrombi, neutrophilic infiltrate, old / recent hemorrhage and edematous avascular villi
  • Dysmorphic villi and villous trophoblastic hyperplasia are suggestive of an abnormal karyotype (Mod Pathol 1998;11:762)
  • Second trimester abortions show focal decidual necrosis, intradecidual hemorrhage, congestion / thrombosis of maternal vessels and avascular villi
Differential diagnosis
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