Editing OBGYN - Normal and Abnormal Labor

=Labor: Normal, Abnormal, and Points Between=

==Definitions==
*Labor: regular / rhythmic contractions, cervical dilation and effacement.
**'''Must have cervical change''' to call it labor.
**Dilation: cervix develops a wider opening.
**Effacement: becomes shorter.
*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.
**'''Relaxin does not play a role in humans.'''
**When 17 alpha-hydroxyprogesterone caproate is given, we see fewer preterm contractions '''so we know progesterone plays a role but we don't see it physiologically'''.
**'''Progesterone levels don't drop until after the ''placenta'' is delivered.'''


*Gap juctions of the uterine smooth muscle are increased near term.
**Presumably to augment myofiber-myofiber communication for a well sequenced contraction.
**Allow easy ability for electrical potential to cross.


*Oxytocin, surprisingly, shows '''no change in blood levels''' but there are '''increased number of oxytocin receptors'''.
**Oxytocin receptors, however are elevated.
**Oxytocin does promote the influx of calcium ions (and therefore increased contractions).
**There is a '''paracrine oxytocin production''' from the ''dicidual and placenta'' with subsequent increase in receptors in the myometrium.
**Made in the posterior pituitary.


*Several prostaglandins are elevated for labor: PGE1, PGE2, PGF2alpha
**Makes collagenase to help '''break down collagen of the cervix to allow dilation and effacement.'''


*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.
**Intermediate reactions in the labor pathway.
**'''Infections can sometimes induce these types of cytokines and thus ''induce labor'''''.
**NO is another intermediate reactor.

==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===
*With fetal monitoring we are concerned with the baby's heart rate and the uterine pressure.
*There are several technical methods for fetal monitoring.
**We can monitor externally via ultrasound and pressure transducers.
**We can monitor internally (if the membranes are ruptured) by putting a pressure transducer into the uterine cavity.
***A clip on the baby's scalp can mark each R wave.

====Fetal Monitoring - Normals====
*'''For baby's heart rate, the baseline should be around 110-160 bpm.'''
*We are looking for: variability, accelerations / decelerations
*For uterine pressure (contractions) we are looking for: '''frequency, duration, uterine tone.'''
**Tone is important because the baby gets better blood flow when the uterus is resting.

====Variability and Accelerations / Decelerations====
*Variability:
**Absent: 0-2 bpm
***Start worrying about fetal acidosis.
***Fix the environment or get the baby out.
**Minimal: 3-5 bpm
**'''Moderate: 6-25 bpm''' (ideal).
**Marked: saltatory, >25 bpm


*Fetal Monitoring:
**Good, classic accelerations '''go up by 15 beats per minute and last for 15 seconds'''.
**If the pregnancy is less than 34 weeks, "10x10" is acceptable.

=====Decelerations=====
*'''Early declerations: occur with cntx'''
**Start and end with the contraction
**'''Non worrisome'''
**Head compression leads to vagal stimulation at the posterior fontanelle
**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.
**Occurs due to chemoreceptors in the carotid arch that sense the decreased pO2 leading to vasoconstriction and then bradycardia
*'''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'''

====Categories of Heart Tracings====
*Category 1:
**Baseline rate: 110-160 bpm
**Baseline FHR variability is moderate
**Accelerations: present or absent
**Late or variable decelerations absent
*Early decelerations present or absent


*Category 2:
**Everything not in 1 or 3


*Category 3:
**Absent baseline variability ('''recall, a sign of acidosis''')
**Recurrent late decelerations
**Recurrent variable decelerations
**Bradycardia
**Sinusoidal pattern ('''a sign of fetal hypoxia with severe anemia'''; think Rh disease)

===Fetal Lie, Presentation, Attitude, and Position===
*Clinical: abdomenal palpation, auscultation of fht’s, vaginal exam
*Studies: u/s, x-ray, MRI
**These are done very rarely as we can determine the lie and presentation rather easily via physical examination.

====Definitions====
*'''Lie: relation of long axis of fetus to long axis of mother.'''
**Longitudinal
**Transverse
**Oblique


*'''Presentation: part of baby foremost in the pelvis'''
**Cephalic
**Breech (bottom)
**Shoulder
**Face
**'''Compound:'''
***Head / hand -> watch (usually resolves itself; may apply a noxious stimuli to the hand)
***Head / foot-> c-section (will not resolve itself; requires c/s)
*Cord prolapse (funic presentation): an '''emergency'''.
**When the cord drops into the vagina.
**Must move quickly to c/s.


*'''Attitude: how the baby presents its head'''
**Normal attitude is folded on itself w/ flexed head


*'''Position: relation of presenting part to maternal pelvis anterior aspect'''
**When the baby ''presents cephalically'', the reference point on the baby to be referenced to the anterior pubis of the mother is the '''occiput'''
**When the baby ''presents facially'', the reference point is the '''mentum'''
**When the baby ''presents as a breech'', the reference point is the '''sacrum'''
**When the baby ''presents transverse'' (shoulder), the reference point is the '''acromion process'''

====Fetal Attitude====
*There are a variety of ways the fetus can present at the os; these are called attitudes:
**Full flexion (A)
***Normal, smallest diameter.
**Military attitude (B)
**Brow presentation (C)
**Face presentation (D)
http://www.glowm.com/resources/glowm/graphics/figures/v2/0760/001f.gif


*Leopold’s Maneuver can be used to determine the attitude of the fetus.
**First maneuver: what is occupying the fundus?
***Soft like a butt or hard like a head?
**Second maneuver: on which side is the fetal spine?
***Third maneuver: what is presenting at the pelvis?
***Soft like a butt or hard like a head?
**Fourth maneuver: what is the attitude, based on the flexion / extension of the head?
*Can correlate with CT if there is any questions.

http://www.sciencephoto.com/image/288555/350wm/M8000133-Leopold_s_Maneuver-SPL.jpg

====Vaginal Exam====
*We are trying to determine if the cervix is starting to dilate or efface.
*We describe effacement as a percent of normal length:
**Normal length of a cervix is 4cm.
**So if the cervix is observed as being 2 cm effaced, we call it 50%.


*Station: the lowest point of the fetus in reference to the ischial spines.
**The stating is described as -1 (and so on, for every centimeter) it is above the ischial spines.
**The station is described as +1 (and so on, for every centimeter) it is below the ischial spines.


*Position:
**Most common is cephalic.
**Use the occiput as the baby reference point when describing position against the maternal anterior pubis.
**'''"right" and "left" shifts describe maternal right and left'''
**To determine which aspect is the occiput, recall there are ant and post fontanelles (along which to orient) and the frontal suture (to identify the anterior aspect of the baby).


*Pelvimetry:
**Performed at the first pre-natal visit and upon admission for L&D.
**Describes adequacy of the pelvis for baby delivery.
**Measures pelvic inlet, the midpelvis, and the pelvic outlet.

=====Pelvic Inlet=====
*True pelvic inlet measurement is from superior pubic ramus to the sacral prominence.
**However, this can't be measured directly so we measure it indirectly.
**True conjugate is also called the obstetric conjugate.


*The diagonal conjugate is measured with one's third finger, along toward the thumb.
*'''True obstetric conjugate = diagonal conjugate – 1.5 to 2.0 cm'''


*'''Diagonal conjugate: >11.5 cm is adequate'''

=====Midpelvis=====
*Sacrum – hallow versus shallow (flat):
**Hallow is concave like a bowl of soup and gives ''more room for baby moving''.


*Ischial spines – blunt vs. prominent
**blunt is better; more room


*Pelvic sidewalls
**Parallel = OK
**Divergent = good
**Convergent = bad

=====Pelvic Outlet=====
*Bituberous diameter:
** > 6-8 cm is good
**Measured by placing fist up against the butt.


*Pubic arch:
** > 90 degrees is good

===Stages of Labor===
*1st Stage: beginning of cervical dilation to complete dilation (10 cm)
*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
**Big fluid shift, high risk of post-partum hemorrhage.
**Monitoring mom for vitals
**Monitoring firmness of uterus (should remain firm to inhibit hemorrhage by pressing layers of endometrium together)

===Cardinal Movements of Labor====
*Engagement
*Flexion (of the head)
*Descent
*Internal rotation
*Extension
*External rotation
*Expulsion


*If the face is anterior, it can still extend.
*If ''mentum-posterior'', there can be no extension, so it cannot deliver.

===Labor Curve===
*The first phase of minimal cervical change is latent phase.
**Minutes, hours, days!
*Active phase
**> 1 cm change / hour
*Baby will move from -5cm station to 0 to +5 as it delivers.

===Prolonged / Arrested Labor===
*When labor isn't moving along, consider your '''3 Ps'''
*'''P'''ower: uterine contractions
**Are they strong enough?
**Give oxytocin?
*'''P'''elvis: adequate?
**Do your pelvimetry to make sure pathway is sufficient
*'''P'''assenger: EFW, position / attitude
**Is the baby too big?
**Is the position wrong? (occiput posterior)
**Is the attitude wrong? (military)

===Dysfunctional Labor===
{|border=1
!Pattern
!Nullip
!Multip
!Rx
|-
!Prolonged latent phase
|>20 hr
|>14 hr
|Rest, AROM (augmented rupture of membranes; helps augment maternal environment for labor), Pitocin (oxytocin)
|-
!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.
**"Cut Cut"
*Francois Rousset (1581)
**First reported case with survival.
**Questionable
*Max Sanger (1882)- Leipzig
**Work on the American frontier
**Sewed the womb shut!  (Whoa!)
**Crazy b/c the womb was considered an awful, evil thing, that shouldn't be sewn shut b/c all those bad humors would stay inside!


*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
**The most common way because it runs with the grain of the muscular fibers.
**Also, this area does less labor contracting so next pregnancy is less likely to result in rupture.
*Low verticle
*Classical
*Kerr

====C-section - Indications====

=====Fetal C-section Indications=====
*Distress / intolerance of labor
**'''FHT of category 2 or 3'''
*Malpresentation (breech, transverse)
*Twins, multiples
**'''Vertex / Vertex = allow to labor'''
*Some congenital anomalies
**NTD

=====Maternal-Fetal C-section Indications=====
*'''Arrest of active labor'''
**Pretty common
*Failed induction of labor (?)
*'''Placenta previa, vasa previa'''
**When the placenta covers the cervical os.
**When the placental vessels course between baby and os.
***50% mortality post-rupture!
*Active HSV outbreak
*HIV+ (viral load >1000/ml)
**If mom is on ARV therapy, there is no decrease in transmission with c/s.
*EFW > 4500 - '''5000 grams''' (increasing risk of shoulder dystocia)
**Use u/s to estimate weight.

=====Maternal C-section Indications=====
*Obstructive tumors (some leiomyomas)
*Severe condylomata acuminata
*Cervical cancer
*Abdominal cerclage
*'''Prior c-section'''
**Risk of uterine rupture is 0.5-1%
**Can be catastrophic
*Prior vaginal colporrhaphy
*Vaginal delivery contraindicated medically
*Pregnant???
**No!

====C-section - Risks====
*At time of surgery / Immediate post-op
*'''Infection: endometritis, wound infection, septic pelvic thrombophlebitis (SPT)'''
*Bleeding: transfusion, hysterectomy
*Damage to fetus
**Very small; no larger than with vaginal delivery.
*Damage to adjacent organs


*Subsequent pregnancy:
**Adhesions
**Uterine rupture
**Placenta previa (when the placenta covers the os) may convert to accreta (when the placenta invades the myometrium).
**Accreta carries huge risks because there is often massive bleeding.
**Accreta puts the mother a risk of death.
**'''That is, placenta previa with a previous c/s has a very high risk of being bad!'''
***0 –> 5% (number of previous c/s, risk of accreta given a placenta previa)
***1 –> 24%
***2 –> 48%
***3 –> 67%
 There will be a test question on prior c/s and placenta previa.


===Operative Vaginal Delivery===
*Forceps and vacuum can be used to guide the baby's head out of the pelvis.
*There are many different types and procedures.

====Operative Vaginal Delivery - Classification====
*We want, first, to be sure the baby has reached the pelvic inlet.

*Didn't talk about any of this:
*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!'''
**Before we put anything on the baby's head, we have to know the position so we don't break the nasal bone or deform the child.
*Adequate pelvis
*Adequate anesthesia

====Operative Vaginal Delivery - Forceps Assisted====
*Use the same angles when applying traction.
*Apply the extension just like in a non-operative vaginal delivery.

====Operative Vaginal Delivery - Risks====
*Maternal:
**Vaginal / perineal trauma, damage to rectal sphincter
**Mostly forceps issues with mom
*Fetal:
**Mostly vacuum issues with baby
**Cephalohematoma
**Subgaleal hemorrhage
**Bony facial trauma
**Facial nerve injury
**Intraventricular hemorrhage

====Birth Trauma====
*Caput succedaneum:
**Very common
**Crosses midline
*Subgaleal hemorrhage:
**Does not cross midline
**Rare
**Hypovolemia and DIC

===Common Post Partum Problems===
*PP Hemorrhage: >500cc (>1000cc for c/s):
**Atony
***When the uterus won't contract.
***Linings aren't collapsed together to stop bleeding.
**Lacerations (cervix, vagina, perineum)
**Retained placenta
***Keeps the endometrium layers from coapting (collapsing together).
**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
**'''Treat with broad spectrum antibiotics'''

====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)