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Placental findings in specific newborn/fetal or maternal conditions

Spontaneous abortion

Reviewers: Mandolin Ziadie, M.D. (see Reviewers page)
Revised: 17 November 2011, last major update November 2011
Copyright: (c) 2003-2011, PathologyOutlines.com, Inc.


● 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 non-specific (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

Micro 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

● Complete / partial moles: villous trophoblastic hyperplasia; hydropic villi with abnormal contours and cistern formation; atypia (Mod Pathol 1998;11:762)

End of Placenta > Placental findings in specific newborn/fetal or maternal conditions > Spontaneous abortion

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