Products of conception

Products of conception, abbreviated POC, is stuff formed from the union of egg and sperm. This article covers POC superficially.

There are separate articles for chorionic villi and gestational trophoblastic disease.

History

• Therapeutic abortions - may be abbreviated "MVC" (manual vacuum aspiration).

Microscopic

Features:

• Chorionic villi are need to call POC - key feature.
  • Cytotrophoblast.
  • Centre of villi often have fetal red blood cells (which have nuclei) -- not required for diagnosis of POC.
• Should have decidual reaction of endometrium.
  • Decidual changes -- mnemonic NEW:
    • Nucleus central.
    • Eosinophilic cytoplasm.
    • Well-defined cell borders.
• Embryo or fetus - a bonus.
• +/-Hyaline globules.

Image:

• Decidualization due to OCP - high mag. (WC).

Aside:

• Embryo = conceptus before 8 weeks.
• Fetus = conceptus 8th weeks 'til birth.

Beta-hCG

Calculator: http://www.countdowntopregnancy.com/tools/beta_doubling_calculator.php

Ectopic pregnancy

• Chorionic villi have to be identified (in some location, e.g. Fallopian tube) to Dx a pregnancy.
• Endometrium: decidual reaction, as seen in any pregnancy.

Arias-Stellas reaction

• Large nuclei - to the novice... it looks really scary.
• NC ratio is preserved.
• May see nuclear clearing.

Screening tests

First trimester screen

• PAPP-A.
• Nuchal translucency.
• beta-hCG.

Maternal serum screen

• Alpha-fetoprotein.
• Beta-hCG.
• Estriol.

Diagnostic tests

• Chorionic villus sampling (10-12 weeks???).
• Amniocentesis (15-16 weeks+).

See also

• Gynecologic pathology.
• Chorionic villi.
• Gestational trophoblastic disease.