Pathology of Pregnancy

Question 1

What is a way to think about the pathology and divide up the differentials?

Answer 1

Early Pregnancy:

• miscarriage
• ectopic pregnancy
• gestational trophoblastic disease

2nd/3rd Trimester:

• Abruption
• Ascending infection
• Variations in placentations and implantation
• Cord complications
• Placental infarction

Post-natal:

• Retained placenta
• PPH

Question 2

What are some causes of spontaneous abortion/miscarriage?

Answer 2

• Foetal causes:
  
  • chromosomal abnormality
  • karyotype in habitual abortion
• Maternal
  
  • Defective implantation (placenta)
  • uterine abnormality (fibroids)
  • infection
  • trauma
• early pregnancy:
  
  • macroscopic - decidual cast (smooth on one side, rough on other, firm), placental (spongey, friable, floats)
  • micro - villi

Question 3

What is an ectopic pregnancy? What are you worried about?

Answer 3

• implantation of the conceptus outside the uterine cavity
  
  • tubal
    
    • ampulla
    • isthmus
    • intersitial
  • abdomen
  • ovary
  • cervic
  • 1-3% synchronous
• Complications:
  
  • worried about tubal rupture and haemorrhage
  • tubal abortion out the end

Question 4

What are some RFs for ectopic pregnancy?

Answer 4

• prior tubal surgery
• tubal ligation
• previous ectopic pregnancies
• IUCD
• tubal pathologies (PID, Salpingitis, endometriosis)

Question 5

Gestational trophoblastic disease, what is it? What is the spectrum?

Answer 5

Don’t need to know specifics just that it exists

• partial hydratidiform mole (partial, complete, invasive), placental site tumour, cholangiocarcinoma.
• complete mole = whole paternal DNA
  
  • more common in asian women
• partial mole - 2 sets of paternal
  
  • 69 chromosomes

Question 6

What are some general reasons for placental exmaination? What kind you find? why is it useful?

Answer 6

Reasons:

• mother disorders
• foetus looks sick
• placenta looks odd

Common problems:

• ascending infections/chorioamnionitis
• infarction
• retroplacental haemorrhage

Useful why?

• causes of adverse outcomes
• recurrence risk
• zygosity of multiple pregnancies

Question 7

What are the common sites of umbilical cord insertion?

Answer 7

• central
• eccentric
• marginal (battledore) - within 10cm of placental margins
  
  • vessels adjacent to membrane - vasa praevia (vessels lie in front of presenting part)
• velamentous
  
  • directly into membranes - risk vessel compression/thrombosis/rupture - edge of vessel rupture.
• marginal and velamentous are a concern.

Question 8

What is Chorioamnionitis? What is used to assess severity?

Answer 8

• ascending intrauterine infection
• major cause of premature labour
• associated with:
  
  • fetal distress
  • placental abruption
  • fetal infection
• Severity:
  
  • maternal inflammatory response
    
    • neutrophils
  • foetal inflammatory response
    
    • umbilical cord vasculitis
    • chorionic vasculitis

Question 9

What causes placental infarction? What is the significance?

Answer 9

• localised obstruction of maternal uteroplacental circulation
• common at term in the periphery 5%
• causes:
  
  • thrombosis
  • retroplacental haematoma
• significance:
  
  • 10% of tissue may be lost before a problem
  • central is worse than peripheral for obstruction, associated with preeclampsia
  • earlier in gestation it is worse

Question 10

What is retroplacental haematoma? What are the effects?

Answer 10

• seperates at the basal plate and uterine wall
• rupture of decidual arterioles and spiral arteries
• can be small and subclinical
• acute can be massive

Effects:

• maternal haemorrhage +/- shock and anaemia
• fetal anorexia
• increased preterm and stillbirths