Obstetrics

Placenta Anatomy

Fetal Sonographic Parameters

• Crown-rump length (CRL)
• Biparietal diameter (BPD)
• Head circumference (HC)
• Abdominal circumference (AC)
• Femur length (FL)

Hormone Changes During Pregnancy

Item	Hormones	Sources
W	Human chorionic gonadotropin (hCG)	Placenta
	17-Hydroxyprogesterone	Corpus luteum
X	Human placental lactogen (hPL)	Placenta
	Progesterone	Corpus luteum Placenta
	Estriol	Placenta
Y	Corticotropin-releasing hormone (CRH)	Placenta

Stages of Labor

Stage	Phase	Events	Primipara	Multipara
1	Latent	Effacement Dilation: 0 → 6 cm Engagement Descent: high → 0	< 20 hours	< 14 hours
	Active	Dilation: 6 → 10 cm Descent: 0 → +2	> 0.7 cm/h	> 1 cm/h
2	-	Expulsion :: fetus	< 2 hours < 3 hours if epidural	< 1 hours < 2 hours if epidural
3	-	Expulsion :: umbilical cord & placenta	< 30 minutes	< 30 minutes

Stages of Labor

Stage	Phase	Events	Primipara	Multipara
1	Latent	Effacement Dilation: 0 → 6 cm Engagement Descent: high → 0	< 20 hours	< 14 hours
	Active	Dilation: 6 → 10 cm Descent: 0 → +2	> 0.7 cm/h	> 1 cm/h
2	-	Expulsion :: fetus	< 2 hours < 3 hours if epidural	< 1 hours < 2 hours if epidural
3	-	Expulsion :: umbilical cord & placenta	< 30 minutes	< 30 minutes

Bishop Score

• Position
• Consistency
• Effacement
• Dilation
• Station

Factors Affecting the Duration of Labor {3P}

• Passenger
• Pelvis
• Power

Passenger

• Attitude: flexed & neutral & extended
• Lie: longitudinal & oblique & transverse
• Presentation
  • Cephalic: vertex [occiput] & sinciput & brow & face & chin
  • Breech: complete & incomplete & frank & footling
  • Shoulder: arm & shoulder & trunk
• Positions
  • Anterior: right anterior & anterior & left anterior
  • Transverse: right transverse & left transverse
  • Posterior: right posterior & posterior & left posterior

Pelvis

Class	Shape	Ischial Spines	Favorable Positions
Gynecoid	Round	Non-prominent	All
Android	Heart	Prominent	None
Anthropoid	Vertical ellipse	Prominent	OA & OP
Platypelloid	Horizontal ellipse	Non-prominent	Tranverse