Problems in Placenta

• The normal placenta

  • Weight - 500 grams (⅙ of the fetus)
  • Diameter - 15 - 20 cm
  • Thickness - 1.5 - 3 cm

  
• In certain disease (syphilis or erythroblastosis)

  Placenta weight is half of the weight of the fetus
• Placenta succenturiata

  A placenta that has one or more accessory lobes connected to the main placenta by blood vessels

  
• No fetal abnormality is associated with placenta succenturiata

  
• The small lobes may be retained in the uterus (severe maternal hemorrhage)

  
• There is a leash of blood vessels running through the membranes connecting succenturiate lobe to main placental disc
• Inspection of placenta

  • Placenta appears torn at the edge or torn blood vessels extend beyond the edge of the placenta
  • Remaining lobes must be recognized and removed from the uterus manually, the uterus will contract as usual with no adverse maternal effects

  
• Placenta circumvallata

  The fetal side of the placenta is covered to some extent with chorion

  
• Inspection of placenta circumvallata

  • The umbilical cord enters the placenta at the usual midpoint
  • Large vessels spread out from there but end abruptly at the point where the chorion folds back onto the surface
  • Placenta marginata - the ring is formed at the margin of the chorionic plate and the fetal vessels appears to terminate

  
• Battledore placenta

  The cord is inserted marginally rather than centrally
• Battledore placenta has no known clinical significance
• Velamentous insertion of the cord


  The cord that instead of entering the placenta directly, separates into small vessels that reach the placenta by spreading across a fold of amnion

  
• Most frequently found in multiple gestation
• Associated with fetal anomalies (fetal blood supply may not be adequate)
• Vasa previa

  The cord of the velamentous cord insertion cross the cervical os
• It is delivered before the fetus
• Vessels may tear with cervical dilatation
• If sudden painless bleeding occurs at the beginning of cervical dilatation, either placenta previa or vasa previa is suspected
• Confirmed by ultrasound
• Delivery is by CS
• Management of vasa previa

  1. Hysterectomy

  2. Methotrexate to destroy the still attached tissue
• Absence of one umbilical artery


  Associated with congenital heart and kidney anomalies
• Inspection of the cord immediately right after delivery before it gets dry (drying distorts the appearance of the vessel)