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• Labor


  The process by which the fetus, placenta, and amniotic membranes are expelled from the uterus
• Parturient


  Woman in labor
• 6 P's of labor

  • Passenger
  • Passageway
  • Power
  • Position
  • Psyche or perception
  • Parity
• Passenger


  • Fetus: 2.5kg – 4 kg or 5.5lb-8.8lb
  • Placenta: 400g or 1 lb (500 at term)
  • Amniotic Fluid: 2 lbs
  • Amniotic fluid volume: 500 to 1000 ml
• Oligohydramnios


  Less than 500 ml of amniotic fluid
• Polyhydramnios


  More than 2000 ml of amniotic fluid
• Normal presentation


  • Cephalic
• Normal position


  • Occiput anterior (LOA)
• Normal lie


  • Longitudinal / Vertical
• Normal attitude


  • Vertex (complete flexion)
• Cephalic prominence


  Suboccipitobregmatic (9.5cm)
• Anterior fontanel


  Structure located between frontal and parietal bones
• Bregma


  Anterior fontanel
• Posterior Fontanel


  Structure located between parietal and occipital bones
• Lambda


  Posterior fontanel
• Cranial sutures


  • Metopic
  • Coronal
  • Sagittal
  • Lambdoid
• Fetal head diameters


  • Mento-Vertical
  • Sub-mento-Vertical
  • Sub-mento-Bregmatic
  • Occipito-Frontal
  • Sub-occipito-Frontal
  • Sub-occipito-Bregmatic
• Transverse diameter of head

  • Bi-Mastoid
  • Bi-Temporal
  • Bi-Parietal
• Fetal presentation


  • Cephalic
  • Breech
  • Shoulder
• Cephalic presentation


  Head at the lower pole of uterus, Vertex - most common (occiput or the small triangular portion of head comes first)
• Cephalic presentation types


  • Vertex
  • Sinciput
  • Brow
  • Face
• Breech presentation types


  • Complete breech
  • Frank breech
  • Footling breech
• Internal examination shows that the acromium of the baby lies on the birth canal
• Shoulder presentation


  Most common sign is "turtle sign" - retraction of the baby's head back into the vagina
• Fundal height measurement may not reflect the baby's growth if the presentation is shoulder
• Shoulder dystocia


  Method of delivery: Cesarean section
• Assist delivery of shoulder dystocia


  McRoberts maneuver - hyperflexing the mother's legs tightly to her abdomen to widen pelvis
• Fetal lie


  • Longitudinal
  • Oblique
  • Transverse
• Fetal position


  • LOA - left occiput anterior
  • ROA - right occiput anterior
  • LOP - left occiput posterior
  • ROP - right occiput posterior
• LOP / ROP may cause severe backache during labor
• Severe backache during labor

  Position mother to squatting
• Location of fetal heart tones (FHT)

  Cephalic/vertex: FHR below umbilicus

  Breech: FHR above umbilicus
• Fetal attitude


  • Vertex - complete flexion
  • Military - moderate flexion
  • Brow - poor flexion/partially extended
  • Mentum - completely hyperextended
• Fetal station


  • Negative station (-1 to -5)

  Zero station (at ischial spines)

  Positive station (+1 to +5)
• Ischial spines are the anatomic fixed reference point to determine the station of the fetal head
• Passageway


  The birth canal composed of the bony pelvis, cervix, pelvic floor, vagina, vaginal opening
• Types of pelvis


  • Gynecoid
  • Anthropoid
  • Android
  • Platypelloid
• Gynecoid pelvis


  Round brim, pear-shaped, most favorable for vaginal delivery
• Anthropoid pelvis


  Oval brim, allows passage of OP fetus, 2nd most favorable for vaginal delivery
• Android pelvis


  Heart shaped brim, triangular inlet with convergent side walls, poor prognosis for vaginal delivery