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 Definitions 1.3.2.1 Fetal Attitude 1.3.2.2 Vaginal Exam

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
  • 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.

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

• Other Presentations:
  • 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
  • Military attitude
  • brow presentation
  • face presentation

• Leopold’s Maneuver can be used to reposition the fetus into another attitude.

Vaginal Exam

• Nullip Multip

� Vaginal Exam stations fetal head.jpg 000138B4 Macintosh HD BB8E171A: Station � Vaginal Exam (Position) bones fetal head.jpg 000138B4 Macintosh HD BB8E171A: fetal position.jpg 000138B4 Macintosh HD BB8E171A: � Vaginal Exam (Pelvimetry) pelvic inlet.jpg 000138B4 Macintosh HD BB8E171A: transverse diameter.jpg 000138B4 Macintosh HD BB8E171A: Diagonal Conjugate Ischial Spines � Vaginal Exam – Pelvic Inlet . Diagonal conjugate >11.5 cm = adequate . Diagonal conjugate – 1.5 to 2.0 cm = True Obstetric conjugate

DiagonalConjugate � Vaginal Exam - Midpelvis . Ischial spines – blunt vs. prominent . Pelvic sidewalls . Parallel = OK . Divergent = good . Convergent = bad

. Sacrum – hallow vs. shallow (flat)

ProminenceoftheSpines � Vaginal Exam – Pelvic Outlet . Bituberous diameter >6- 8 cm . Pubic arch >90 degrees

TransverseOutlet � Stages of Labor . 1st- beginning of cervical dilation to complete dilation . 2nd- complete dilation to delivery of fetus . 3rd- delivery of placenta (up to 30 min.) . 4th- first hour after delivery of placenta

� Cardinal Movements of Labor . Engagement . Flexion . Descent . Internal rotation . Extension . External rotation . Expulsion

cardinal.jpg 000138B4 Macintosh HD BB8E171A: � Labor Curve scan1.jpg 000138B4 Macintosh HD BB8E171A: � 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

-National Center for Health Studies � C-section - Techniques uterine incision.jpg 000138B4 Macintosh HD BB8E171A: � C-section - Indications . Fetal . Distress/intolerance of labor . Malpresentation (breech, transverse) . Twins, multiples . Vtx/Vtx = allow to labor

. Some congenital anomalies . NTD

� C-sections – Indications (cont.) . Maternal-Fetal . 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)

� C-section – Indications (cont.) . Maternal . 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

� C-section – Risks (cont.) . Subsequent pregnancy . Uterine rupture . Placenta previa->accreta . 0 –> 5% . 1 –> 24% . 2 –> 48% . 3 –> 67%

. Adhesions

� Operative Vaginal Delivery . Forceps and vacuum

forceps.jpg 000138B4 Macintosh HD BB8E171A: � Classification of Delivery . 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

� Indications for Operative Vaginal Delivery . Nonreassuring FHT’s . Prolonged 2nd stage of labor . Shortened 2nd stage if pushing/Valsalva not indicated . Maternal exhaustion

� Prerequisites for Operative Vaginal Delivery . Cervix completely dilated . Ruptured membranes . Fetal skull engaged in pelvis . Empty bladder . Position! Position! Position! . Adequate pelvis . Adequate anesthesia

� Forceps Assisted Vaginal Delivery hrphysioL08 � Risks of Operative Vaginal Delivery . 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

2925 vacuum-fig1 � 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

� PP Problems (cont.) . Endometritis- Fundal tenderness w/ T>38°C x 2 or >38.5°C . Polymicrobial infection . More common after c/s . Prolonged ruptured membranes . chorioamnionitis

� PP/Post-Op Fever . Wind . Wound . Water . Walk . Wonder drug . Womb . Wean

. Atelectasis, pneu . Seroma, nec. Fasc. . UTI . Thrombophlebitis . Drug rxn . Endometritis . Mastitis, engorgement

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