NCM109 RLE Midterms

• Rhesus factor (Rh factor)


  A type of protein found on the outside of red blood cells

  
• Rh factor types


  • Rh-positive (have the protein)
  • Rh-negative (don't have the protein)

  
• The majority of people, about 85%, are Rh-positive
• If you're Rh-negative and the fetus is Rh-positive


  Rh factor incompatibility can occur

  
• Rh incompatibility


  When a person who's Rh-negative becomes pregnant with a fetus with Rh-positive blood, causing the immune system to create antibodies that attack the fetus's red blood cells
• How Rh incompatibility can occur


  Small amount of fetal blood mixes with maternal blood during labor, delivery, tests like amniocentesis, vaginal bleeding, injury/trauma, early pregnancy complications, external cephalic version

  
• Complications don't usually happen during a person's first pregnancy, as it's unlikely the blood will mix until delivery
• If a person becomes pregnant a second time with an Rh-positive fetus


  Their body will produce antibodies that can attack the fetus's red blood cells, causing Rh disease
• Fetal Rh factor risk based on parents' Rh factors

  • Pregnant parent Rh-positive, other parent Rh-positive: Fetus Rh-positive, no risk
  • Pregnant parent Rh-negative, other parent Rh-negative: Fetus Rh-negative, no risk
  • Pregnant parent Rh-positive, other parent Rh-negative: Fetus could be either, no risk
  • Pregnant parent Rh-negative, other parent Rh-positive: Fetus could be either, high risk, Rh immune globulin necessary

  
• Rh factor test


  A blood test done in the first trimester to determine a pregnant person's Rh factor

  
• How Rh incompatibility is diagnosed and managed

  If Rh-negative, antibody screen is done. If negative, Rh immune globulin is given around 28 weeks and after delivery if fetus is Rh-positive. If antibodies are present, close monitoring for fetal Rh disease is required.

  
• Rh immune globulin (RhIg or RhoGAM)


  A medication that stops the body from making Rh antibodies, preventing complications of Rh incompatibility

  
• Since the development of Rh immune globulin, Rh disease occurs infrequently

  
• Lie


  The relationship between the long axis of the fetus and the mother (longitudinal, transverse or oblique)

  
• Presentation


  The fetal part that first enters the maternal pelvis (cephalic vertex is most common and safest, other presentations include breech, shoulder, face, brow)

  
• Position


  The position of the fetal head as it exits the birth canal (usually occipito-anterior is ideal)

  
• Breech presentation is the most common malpresentation
• Risk factors for abnormal fetal lie, malpresentation and malposition

  • Prematurity
  • Multiple pregnancy
  • Uterine abnormalities (e.g. fibroids, partial septate uterus)
  • Fetal abnormalities
  • Placenta previa
  • Primiparity

  
• Management of abnormal fetal lie


  External cephalic version (ECV) can be attempted between 36-38 weeks to manipulate the fetus to a cephalic presentation

  
• External cephalic version (ECV)


  • Has a success rate of 50% in primiparous women and 60% in multiparous women
  • Complications are rare but include fetal distress, premature rupture of membranes, antepartum hemorrhage and placental abruption
  • Risk of emergency C-section within 24 hours is around 1 in 200
• ECV is contraindicated in women with recent antepartum hemorrhage, ruptured membranes, uterine abnormalities or previous C-section
• Management of malpresentation


  1. Breech - attempt ECV before labor, vaginal breech delivery or C-section

  2. Brow - C-section necessary

  3. Face - Mento-anterior may allow normal labor, mento-posterior requires C-section

  4. Shoulder - C-section necessary
• 90% of malpositions spontaneously rotate to occipito-anterior as labor progresses
• Management of malposition


  If fetal head does not rotate, rotation and operative vaginal delivery can be attempted, or a C-section can be performed