Presentation (obstetrics)

Presentation of twins in Der Rosengarten ("The Rose Garden"), a standard medical text for midwives published in 1513.

In obstetrics, the presentation of a fetus about to be born refers to which anatomical part of the fetus is leading, that is, is closest to the pelvic inlet of the birth canal. According to the leading part, this is identified as a cephalic, breech, or shoulder presentation. A malpresentation is any presentation other than a vertex presentation (with the top of the head first).

Classification

Thus the various presentations are:

• cephalic presentation (head first):
  • vertex (crown) — the most common and associated with the fewest complications
  • sinciput (forehead)
  • brow (eyebrows)
  • face
  • chin
• breech presentation^[1] (buttocks or feet first):
  • complete breech
  • footling breech
  • frank breech
• shoulder presentation:
  • arm
  • shoulder
  • trunk

Related obstetrical terms

Attitude

• Definition: Relationship of fetal head to spine:
  • flexed, (this is the normal situation)
  • neutral (“military”),
  • extended.

Position

• Definition: Relationship of presenting part to maternal pelvis: and based on presentation:Note fetus enters pelvis in occipito-transverse plane (left or right), descent and flexion then rotates 90 degrees to occipito-anterior (most commonly)
  • Cephalic presentation
    • Vertex presentation with longitudinal lie:^[1]
      • Left occipitoanterior (LOA)—the occiput is close to the vagina (hence known as vertex presentation) faces anteriorly (forward with mother standing) and towards left. This is the most common position and lie.
      • Right occipitoanterior (ROA)—the occiput faces anteriorly and towards right. Less common than LOA, but not associated with labor complications.
      • Left occipitoposterior (LOP)—the occiput faces posteriorly (behind) and towards left.
      • Right occipitoposterior (ROP)—the occiput faces posteriorly and towards right.
      • Occipitoanterior —the occiput faces anteriorly (absolutely straight without any turning to any of the sides)
      • Occipitoposterior —the occiput faces posteriorly (absolutely straight without any turning to any of the sides)
    • Face presentation
  • Breech presentation with longitudinal lie:^[1]
    • Left sacrum anterior (LSA)—the buttocks, as against the occiput of the vertex presentation, like close to the vagina (hence known as breech presentation), which like anteriorly and towards the left.
    • Right sacrum anterior (RSA)—the buttocks face anteriorly and towards the right.
    • Left sacrum posterior (LSP)—the buttocks face posteriorly and towards the left.
    • Right sacrum posterior (RSP)—the buttocks face posteriorly and towards right.
    • Sacrum anterior(SA)—the buttocks face anteriorly.
    • Sacrum posterior (SP)—the buttocks face posteriorly.
  • Shoulder presentation with transverse lie are classified into four types, based on the location of the scapula (shoulderblade); note: this presentation needs to be delivered by cesarean section.
    • Left scapula-anterior (LSA)
    • Right scapula-anterior (RSA)
    • Left scapula-posterior (LSP)
    • Right scapula-posterior (RSP)

Lie

• Definition: Relationship between the longitudinal axis of fetus and mother:
  • longitudinal, (resulting in either cephalic or breech presentation)
  • oskie, (cephalic presentation, fetus legs straight along frontal axis of mother)
  • oblique, (unstable, will eventually become either transverse or longitudinal)
  • transverse (resulting in shoulder presentation).

See also

• Child birth
• Fetal relations
• Position
• Eucharius Rösslin

References

External links

• Malpresentations and malpositions: A guide for midwives and doctors by the WHO
• Normal Labor and Delivery from Management of Labor and Delivery provided by Google books