From Iusmicm

Contents 1 Labor: Normal, Abnormal, and Points Between 1.1 Definitions 1.2 Physiology of Labor 1.3 Labor and Delivery Admission 1.3.1 Fetal Monitoring 1.3.1.1 Variability and Accelerations / Decelerations 1.3.1.1.1 Decelerations 1.3.1.2 Sinusoidal 1.3.2 Fetal Lie, Presentation, Attitude, and Position 1.3.2.1 Definitions 1.3.2.2 Fetal Attitude 1.3.2.3 Vaginal Exam 1.3.2.3.1 Pelvic Inlet 1.3.2.3.2 Midpelvis 1.3.2.3.3 Pelvic Outlet 1.3.3 Stages of Labor 1.3.4 Labor Curve 1.3.5 Prolonged / Arrested Labor 1.3.6 Dysfunctional Labor 1.3.7 Cesarean Section 1.3.7.1 C-section - Techniques 1.3.7.2 C-section - Indications 1.3.7.2.1 Fetal C-section Indications 1.3.7.2.2 Maternal-Fetal C-section Indications 1.3.7.2.3 Maternal C-section Indications 1.3.7.3 C-section - Risks 1.3.8 Operative Vaginal Delivery 1.3.8.1 Operative Vaginal Delivery - Classification 1.3.8.2 Operative Vaginal Delivery - Indications 1.3.8.3 Operative Vaginal Delivery - Prerequisites 1.3.8.4 Operative Vaginal Delivery - Forceps Assisted 1.3.8.5 Operative Vaginal Delivery - Risks 1.3.9 Birth Trauma 1.3.10 Common Post Partum Problems 1.3.10.1 PP / Post-Op Fever

Labor: Normal, Abnormal, and Points Between

Definitions

• Labor: regular / rhythmic contractions, cervical dilation and effacement.
  • Labor is considered "preterm" if it commences before 37 weeks EGA (estimated gestational age)
  • 10-12% of pregnancies include preterm labor.
  • Labor is considered "postdates" if it commences after 42 weeks EGA.
• Braxton Hicks contractions are contractions of a weak or irregular nature.

Physiology of Labor

• There are many factors that play a role in the coordinated contraction of all the uterine smooth muscle for labor.
• Progesterone and Relaxin are key regulating factors in animals.
  • 17alpha-hydroxyprogesterone caproate
• Gap juctions of the uterine smooth muscle are increased near term.
  • Presumably to augment myofiber-myofiber communication for a well sequenced contraction.
• Oxytocin, surprisingly, shows no change in blood levels.
  • Oxytocin receptors, however are elevated.

**Furthermore, there is elevated decidual production.

• Several prostaglandins are elevated for labor: PGE1, PGE2, PGF2alpha
• Mother becomes more sensitive to changes in Ca at term.
  • This is presumably because the uterine muscle is storing up more and more Ca to augment contraction.
• Like prostaglandins, many cytokines are elevated: IL-1, IL-6, IL-8, TNF-alpha.

Labor and Delivery Admission

• The workup for a L&D admission includes:
  • H&P
  • Fetal monitoring
  • Leopold’s maneuver
  • Vaginal exam
    • R/o (rule out) placenta previa and ROM first
    • Cervical dilation / effacement / station and fetal position

Fetal Monitoring

• There are several technical methods for fetal monitoring.
• With fetal monitoring we are concerned with the baby's heart rate and the uterine pressure.

• For baby's heart rate, the baseline should be around 120-160 bpm.
• We are looking for: variability, accelerations / decelerations

• For uterine pressure (contractions) we are looking for: frequency, duration, uterine tone.

Variability and Accelerations / Decelerations

• Variability:
  • Absent: 0-2 bpm
  • Minimal: 3-5 bpm
  • Moderate: 6-25 bpm
  • Marked: saltatory, >25 bpm

• Fetal Monitoring:
  • Accelerations- “15 x 15”

• Reactive fetal heart tracing (nonstress test)
  • 2 accelerations in 20 minutes or less

• Contraction stress test (Oxytocin challenge test)
  • 3 UC’s x 40 sec in 10 mins
  • Negative = no decelerations
  • Positive = >50% UC’s with late decelerations
  • Equivocal = intermittent or late decelerations or significant variable decelerations

Decelerations

• Early declerations: occur with cntx
  • Non worrisome
  • Head compression leads to vagal stimulation
  • Recall that vagus carries parasympathetics to the heart
• Late decelerations: begin at peak of cntx or after
  • Fetal hypoxia is usually the culprit of late decelerations.
• Variable: can occur at any time
  • Variable decelerations should raise one's suspicion for cord compression

• Variable Decelerations: mild, moderate, and severe.
  • Lower the blood pressure the more severe.
  • Longer the duration the more severe.
  • Severity of variable decelerations are a function of blood pressure and duration

Sinusoidal

Fetal Lie, Presentation, Attitude, and Position

• Clinical: abd palpation, auscultation of fht’s, vaginal exam
• Studies: u/s, x-ray, MRI

Definitions

• Lie: relation of long axis of fetus to long axis of mother
  • Longitudinal
  • Transverse
  • Oblique

• Presentation: part foremost in the pelvis
  • Cephalic
  • Breech
  • Shoulder
  • Compound:
    • Head / hand -> watch
    • Head / foot-> c-section
• Cord prolapse (funic presentation): an emergency.

• Attitude: folded on itself w/ flexed head
  • extension of head?

• Position: relation of presenting part to maternal pelvis
  • Cephalic -> occiput
  • Face -> mentum
  • Breech -> sacrum
  • Transverse -> acromion process

Fetal Attitude

• There are a variety of ways the fetus can present at the os; these are called attitudes:
  • Full flexion (A)
  • Military attitude (B)
  • Brow presentation (C)
  • Face presentation (D)

• Leopold’s Maneuver can be used to determine the attitude of the fetus.

Vaginal Exam

• Nullip versus Multip

• Station:

• Position:

• Pelvimetry:
  • Diagonal Conjugate
  • Ischial Spines

Pelvic Inlet

• Diagonal conjugate: >11.5 cm is adequate
• True obstetric conjugate = diagonal conjugate – 1.5 to 2.0 cm

Midpelvis

• Ischial spines – blunt vs. prominent
• Pelvic sidewalls
  • Parallel = OK
  • Divergent = good
  • Convergent = bad
• Sacrum – hallow vs. shallow (flat)

Pelvic Outlet

• Bituberous diameter > 6-8 cm
• Pubic arch > 90 degrees

Stages of Labor

• 1st Stage: beginning of cervical dilation to complete dilation
• 2nd Stage: complete dilation to delivery of fetus
• 3rd Stage: delivery of placenta (up to 30 minutes)
• 4th Stage: first hour after delivery of placenta

===Cardinal Movements of Labor====*Engagement

• Flexion
• Descent
• Internal rotation
• Extension
• External rotation
• Expulsion

Labor Curve

Interpret chart

Prolonged / Arrested Labor

• Power: uterine contractions
• Pelvis: adequate?
• Passenger: EFW, position / attitude

Dysfunctional Labor

Pattern	Nullip	Multip	Rx
Prolonged latent phase	>20 hr	>14 hr	Rest, AROM, Pit
Protracted dilation	<1.2 cm/hr	<1.5 cm/hr	AROM, Pit
Protracted descent	<1 cm/hr	<2 cm/hr	Pit	Arrest of dilation	>2 hr	>2 hr	AROM, Pit, C/S
Arrest of descent	>2 hr	>1 hr	Vacuum, forceps, C/S

Cesarean Section

• History
  • Caedere -> caesura: to cut; seco: to cut.
  • Francois Rousset (1581)
  • Max Sanger (1882)- Leipzig
• Most common surgical procedure
  • 1965 <5%, 1996 - 20.7%, 2004 - 29.1%
  • No change in cerebral palsy rate

C-section - Techniques

• Uterine Incisions:
  • Low transverse
  • Low verticle
  • Classical
  • Kerr

C-section - Indications

Fetal C-section Indications

• Distress / intolerance of labor
• Malpresentation (breech, transverse)
• Twins, multiples
  • Vtx / Vtx = allow to labor
• Some congenital anomalies
  • NTD

Maternal-Fetal C-section Indications

• Arrest of active labor
• Failed induction of labor (?)
• Placenta previa, vasa previa
• Active HSV outbreak
• HIV+ (viral load >1000/ml)
• EFW > 4500 - 5000 gms (increasing risk of shoulder dystocia)

Maternal C-section Indications

• Obstructive tumors (some leiomyomas)
• Severe condylomata acuminata
• Cervical cancer
• Abdominal cerclage
• Prior c-section
• Prior vaginal colporrhaphy
• Vaginal delivery contraindicated medically
• Pregnant???

C-section - Risks

• At time of surgery / Immediate post-op
• Infection: endometritis, wound infection, septic pelvic thrombophlebitis (SPT)
• Bleeding: transfusion, hysterectomy
• Damage to fetus
• Damage to adjacent organs
• Subsequent pregnancy
  • Uterine rupture
  • Placenta previa -> accreta
    • 0 –> 5%
    • 1 –> 24%
    • 2 –> 48%
    • 3 –> 67%
  • Adhesions

Operative Vaginal Delivery

• Forceps and vacuum

Operative Vaginal Delivery - Classification

• Outlet: scalp visible at introitus w/out separating labia; no rotation
• Low: leading point of skull at or below +2 cm station
  • Rotate < 45°
  • Rotate > 45°
• Mid: above +2 cm station but engaged

Operative Vaginal Delivery - Indications

• Nonreassuring FHT’s
• Prolonged 2nd stage of labor
• Shortened 2nd stage if pushing / Valsalva not indicated
• Maternal exhaustion

Operative Vaginal Delivery - Prerequisites

• Cervix completely dilated
• Ruptured membranes
• Fetal skull engaged in pelvis
• Empty bladder
• Position! Position! Position!
• Adequate pelvis
• Adequate anesthesia

Operative Vaginal Delivery - Forceps Assisted

Operative Vaginal Delivery - Risks

• Maternal:
  • Vaginal / perineal trauma, damage to rectal sphincter
• Fetal:
  • Cephalohematoma
  • Subgaleal hemorrhage
  • Bony facial trauma
  • Facial nerve injury
  • Intraventricular hemorrhage

Birth Trauma

• Caput succedaneum:
  • Very common
  • Crosses midline
• Subgaleal hemorrhage:
  • Rare
  • Hypovolemia and DIC

Common Post Partum Problems

• PP Hemorrhage: >500cc (>1000cc for c/s):
  • Atony
  • Lacerations (cervix, vagina, perineum)
  • Retained placenta
  • Uterine rupture
  • Uterine inversion
  • Amniotic fluid embolism
• Endometritis:
  • Fundal tenderness w/ temperature >38°C x 2 or >38.5°C
  • Polymicrobial infection
  • More common after c/s
    • Prolonged ruptured membranes
    • Chorioamnionitis

PP / Post-Op Fever

• Causes and symptoms
  • Wind (atelectasis, pneumonia)
  • Wound (seroma, necrotizing fasciitis)
  • Water (UTI)
  • Walk (thrmobophlebitis)
  • Wonder drug (drug reaction)
  • Womb (endometriosis)
  • Wean (mastitis, engorgement)