OBGYN - Normal and Abnormal Labor

From Iusmicm

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(DgI5m4 Appreciate you sharing, great article post.Much thanks again. Keep writing.)
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=Labor: Normal, Abnormal, and Points Between=
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DgI5m4 Appreciate you sharing, great article post.Much thanks again. Keep writing.
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==Definitions==
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*Labor: regular / rhythmic contractions, cervical dilation and effacement.
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**'''Must have cervical change''' to call it labor.
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**Dilation: cervix develops a wider opening.
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**Effacement: becomes shorter.
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*Labor is considered '''"preterm" if it commences before 37 weeks EGA''' (estimated gestational age)
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**10-12% of pregnancies include preterm labor.
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*Labor is considered '''"postdates" if it commences after 42 weeks EGA.'''
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*'''Braxton Hicks contractions are contractions of a weak or irregular nature.'''
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==Physiology of Labor==
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*There are many factors that play a role in the coordinated contraction of all the uterine smooth muscle for labor.
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*Progesterone and Relaxin are key regulating factors in animals.
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**'''Relaxin does not play a role in humans.'''
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**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'''.
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**'''Progesterone levels don't drop until after the ''placenta'' is delivered.'''
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*Gap juctions of the uterine smooth muscle are increased near term.
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**Presumably to augment myofiber-myofiber communication for a well sequenced contraction.
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**Allow easy ability for electrical potential to cross.
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*Oxytocin, surprisingly, shows '''no change in blood levels''' but there are '''increased number of oxytocin receptors'''.
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**Oxytocin receptors, however are elevated.
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**Oxytocin does promote the influx of calcium ions (and therefore increased contractions).
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**There is a '''paracrine oxytocin production''' from the ''dicidual and placenta'' with subsequent increase in receptors in the myometrium.
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**Made in the posterior pituitary.
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*Several prostaglandins are elevated for labor: PGE1, PGE2, PGF2alpha
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**Makes collagenase to help '''break down collagen of the cervix to allow dilation and effacement.'''
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*Mother becomes more sensitive to changes in Ca at term.
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**This is presumably because the uterine muscle is storing up more and more Ca to augment contraction.
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*Like prostaglandins, many cytokines are elevated: IL-1, IL-6, IL-8, TNF-alpha.
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**Intermediate reactions in the labor pathway.
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**'''Infections can sometimes induce these types of cytokines and thus ''induce labor'''''.
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**NO is another intermediate reactor.
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==Labor and Delivery Admission==
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*The workup for a L&D admission includes:
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**H&P:
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***Fetal monitoring
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***Leopold’s maneuver
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***Vaginal exam
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****R/o (rule out) placenta previa and ROM first
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****Cervical dilation / effacement / station and fetal position
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===Fetal Monitoring===
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*With fetal monitoring we are concerned with the baby's heart rate and the uterine pressure.
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*There are several technical methods for fetal monitoring.
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**We can monitor externally via ultrasound and pressure transducers.
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**We can monitor internally (if the membranes are ruptured) by putting a pressure transducer into the uterine cavity.
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***A clip on the baby's scalp can mark each R wave.
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====Fetal Monitoring - Normals====
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*'''For baby's heart rate, the baseline should be around 110-160 bpm.'''
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*We are looking for: variability, accelerations / decelerations
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*For uterine pressure (contractions) we are looking for: '''frequency, duration, uterine tone.'''
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**Tone is important because the baby gets better blood flow when the uterus is resting.
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====Variability and Accelerations / Decelerations====
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*Variability:
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**Absent: 0-2 bpm
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***Start worrying about fetal acidosis.
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***Fix the environment or get the baby out.
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**Minimal: 3-5 bpm
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**'''Moderate: 6-25 bpm''' (ideal).
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**Marked: saltatory, >25 bpm
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*Fetal Monitoring:
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**Good, classic accelerations '''go up by 15 beats per minute and last for 15 seconds'''.
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**If the pregnancy is less than 34 weeks, "10x10" is acceptable.
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=====Decelerations=====
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*'''Early declerations: occur with cntx'''
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**Start and end with the contraction
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**'''Non worrisome'''
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**Head compression leads to vagal stimulation at the posterior fontanelle
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**Recall that vagus carries parasympathetics to the heart
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*'''Late decelerations: begin at peak of cntx or after'''
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**'''Fetal hypoxia''' is usually the culprit of late decelerations.
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**Occurs due to chemoreceptors in the carotid arch that sense the decreased pO2 leading to vasoconstriction and then bradycardia
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*'''Variable: can occur at any time'''
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**Variable decelerations should '''raise one's suspicion for cord compression'''
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*Variable Decelerations: mild, moderate, and severe.
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**Lower the blood pressure the more severe.
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**Longer the duration the more severe.
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**'''Severity of variable decelerations are a function of blood pressure and duration'''
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====Categories of Heart Tracings====
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*Category 1:
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**Baseline rate: 110-160 bpm
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**Baseline FHR variability is moderate
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**Accelerations: present or absent
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**Late or variable decelerations absent
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*Early decelerations present or absent
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*Category 2:
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**Everything not in 1 or 3
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*Category 3:
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**Absent baseline variability ('''recall, a sign of acidosis''')
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**Recurrent late decelerations
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**Recurrent variable decelerations
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**Bradycardia
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**Sinusoidal pattern ('''a sign of fetal hypoxia with severe anemia'''; think Rh disease)
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===Fetal Lie, Presentation, Attitude, and Position===
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*Clinical: abdomenal palpation, auscultation of fht’s, vaginal exam
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*Studies: u/s, x-ray, MRI
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**These are done very rarely as we can determine the lie and presentation rather easily via physical examination.
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====Definitions====
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*'''Lie: relation of long axis of fetus to long axis of mother.'''
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**Longitudinal
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**Transverse
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**Oblique
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*'''Presentation: part of baby foremost in the pelvis'''
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**Cephalic
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**Breech (bottom)
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**Shoulder
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**Face
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**'''Compound:'''
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***Head / hand -> watch (usually resolves itself; may apply a noxious stimuli to the hand)
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***Head / foot-> c-section (will not resolve itself; requires c/s)
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*Cord prolapse (funic presentation): an '''emergency'''.
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**When the cord drops into the vagina.
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**Must move quickly to c/s.
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*'''Attitude: how the baby presents its head'''
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**Normal attitude is folded on itself w/ flexed head
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*'''Position: relation of presenting part to maternal pelvis anterior aspect'''
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**When the baby ''presents cephalically'', the reference point on the baby to be referenced to the anterior pubis of the mother is the '''occiput'''
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**When the baby ''presents facially'', the reference point is the '''mentum'''
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**When the baby ''presents as a breech'', the reference point is the '''sacrum'''
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**When the baby ''presents transverse'' (shoulder), the reference point is the '''acromion process'''
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====Fetal Attitude====
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*There are a variety of ways the fetus can present at the os; these are called attitudes:
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**Full flexion (A)
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***Normal, smallest diameter.
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**Military attitude (B)
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**Brow presentation (C)
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**Face presentation (D)
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http://www.glowm.com/resources/glowm/graphics/figures/v2/0760/001f.gif
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*Leopold’s Maneuver can be used to determine the attitude of the fetus.
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**First maneuver: what is occupying the fundus?
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***Soft like a butt or hard like a head?
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**Second maneuver: on which side is the fetal spine?
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***Third maneuver: what is presenting at the pelvis?
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***Soft like a butt or hard like a head?
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**Fourth maneuver: what is the attitude, based on the flexion / extension of the head?
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*Can correlate with CT if there is any questions.
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http://www.sciencephoto.com/image/288555/350wm/M8000133-Leopold_s_Maneuver-SPL.jpg
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====Vaginal Exam====
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*We are trying to determine if the cervix is starting to dilate or efface.
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*We describe effacement as a percent of normal length:
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**Normal length of a cervix is 4cm.
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**So if the cervix is observed as being 2 cm effaced, we call it 50%.
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*Station: the lowest point of the fetus in reference to the ischial spines.
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**The stating is described as -1 (and so on, for every centimeter) it is above the ischial spines.
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**The station is described as +1 (and so on, for every centimeter) it is below the ischial spines.
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*Position:
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**Most common is cephalic.
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**Use the occiput as the baby reference point when describing position against the maternal anterior pubis.
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**'''"right" and "left" shifts describe maternal right and left'''
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**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).
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*Pelvimetry:
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**Performed at the first pre-natal visit and upon admission for L&D.
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**Describes adequacy of the pelvis for baby delivery.
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**Measures pelvic inlet, the midpelvis, and the pelvic outlet.
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=====Pelvic Inlet=====
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*True pelvic inlet measurement is from superior pubic ramus to the sacral prominence.
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**However, this can't be measured directly so we measure it indirectly.
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**True conjugate is also called the obstetric conjugate.
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*The diagonal conjugate is measured with one's third finger, along toward the thumb.
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*'''True obstetric conjugate = diagonal conjugate – 1.5 to 2.0 cm'''
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*'''Diagonal conjugate: >11.5 cm is adequate'''
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=====Midpelvis=====
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*Sacrum – hallow versus shallow (flat):
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**Hallow is concave like a bowl of soup and gives ''more room for baby moving''.
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*Ischial spines – blunt vs. prominent
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**blunt is better; more room
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*Pelvic sidewalls
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**Parallel = OK
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**Divergent = good
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**Convergent = bad
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=====Pelvic Outlet=====
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*Bituberous diameter:
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** > 6-8 cm is good
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**Measured by placing fist up against the butt.
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*Pubic arch:
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** > 90 degrees is good
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===Stages of Labor===
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*1st Stage: beginning of cervical dilation to complete dilation (10 cm)
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*2nd Stage: complete dilation to delivery of fetus
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*3rd Stage: delivery of placenta
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**up to 30 minutes
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*4th Stage: first hour after delivery of placenta
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**Big fluid shift, high risk of post-partum hemorrhage.
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**Monitoring mom for vitals
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**Monitoring firmness of uterus (should remain firm to inhibit hemorrhage by pressing layers of endometrium together)
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===Cardinal Movements of Labor====
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*Engagement
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*Flexion (of the head)
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*Descent
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*Internal rotation
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*Extension
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*External rotation
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*Expulsion
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*If the face is anterior, it can still extend.
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*If ''mentum-posterior'', there can be no extension, so it cannot deliver.
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===Labor Curve===
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*The first phase of minimal cervical change is latent phase.
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**Minutes, hours, days!
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*Active phase
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**> 1 cm change / hour
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*Baby will move from -5cm station to 0 to +5 as it delivers.
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===Prolonged / Arrested Labor===
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*When labor isn't moving along, consider your '''3 Ps'''
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*'''P'''ower: uterine contractions
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**Are they strong enough?
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**Give oxytocin?
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*'''P'''elvis: adequate?
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**Do your pelvimetry to make sure pathway is sufficient
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*'''P'''assenger: EFW, position / attitude
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**Is the baby too big?
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**Is the position wrong? (occiput posterior)
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**Is the attitude wrong? (military)
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===Dysfunctional Labor===
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{|border=1
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!Pattern
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!Nullip
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!Multip
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!Rx
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!Prolonged latent phase
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|>20 hr
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|>14 hr
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|Rest, AROM (augmented rupture of membranes; helps augment maternal environment for labor), Pitocin (oxytocin)
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!Protracted dilation
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|<1.2 cm/hr
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|<1.5 cm/hr
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|AROM, Pit
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!Protracted descent
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|<1 cm/hr
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|<2 cm/hr
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|Pit
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!Arrest of dilation
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|>2 hr
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|>2 hr
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|AROM, Pit, C/S
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|-
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!Arrest of descent
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|>2 hr
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|>1 hr
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|Vacuum, forceps, C/S
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|}
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===Cesarean Section===
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*History
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**''Caedere -> caesura'': to cut; ''seco'': to cut.
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**"Cut Cut"
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*Francois Rousset (1581)
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**First reported case with survival.
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**Questionable
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*Max Sanger (1882)- Leipzig
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**Work on the American frontier
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**Sewed the womb shut!  (Whoa!)
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**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!
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*Most common surgical procedure
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**1965: <5%, 1996: 20.7%, 2004: 29.1%
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*No change in cerebral palsy rate
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====C-section - Techniques====
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*Uterine Incisions
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*Low transverse
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**The most common way because it runs with the grain of the muscular fibers.
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**Also, this area does less labor contracting so next pregnancy is less likely to result in rupture.
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*Low verticle
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*Classical
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*Kerr
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====C-section - Indications====
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=====Fetal C-section Indications=====
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*Distress / intolerance of labor
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**'''FHT of category 2 or 3'''
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*Malpresentation (breech, transverse)
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*Twins, multiples
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**'''Vertex / Vertex = allow to labor'''
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*Some congenital anomalies
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**NTD
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=====Maternal-Fetal C-section Indications=====
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*'''Arrest of active labor'''
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**Pretty common
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*Failed induction of labor (?)
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*'''Placenta previa, vasa previa'''
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**When the placenta covers the cervical os.
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**When the placental vessels course between baby and os.
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***50% mortality post-rupture!
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*Active HSV outbreak
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*HIV+ (viral load >1000/ml)
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**If mom is on ARV therapy, there is no decrease in transmission with c/s.
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*EFW > 4500 - '''5000 grams''' (increasing risk of shoulder dystocia)
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**Use u/s to estimate weight.
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=====Maternal C-section Indications=====
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*Obstructive tumors (some leiomyomas)
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*Severe condylomata acuminata
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*Cervical cancer
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*Abdominal cerclage
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*'''Prior c-section'''
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**Risk of uterine rupture is 0.5-1%
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**Can be catastrophic
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*Prior vaginal colporrhaphy
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*Vaginal delivery contraindicated medically
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*Pregnant???
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**No!
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====C-section - Risks====
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*At time of surgery / Immediate post-op
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*'''Infection: endometritis, wound infection, septic pelvic thrombophlebitis (SPT)'''
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*Bleeding: transfusion, hysterectomy
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*Damage to fetus
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**Very small; no larger than with vaginal delivery.
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*Damage to adjacent organs
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*Subsequent pregnancy:
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**Adhesions
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**Uterine rupture
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**Placenta previa (when the placenta covers the os) may convert to accreta (when the placenta invades the myometrium).
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**Accreta carries huge risks because there is often massive bleeding.
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**Accreta puts the mother a risk of death.
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**'''That is, placenta previa with a previous c/s has a very high risk of being bad!'''
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***0 –> 5% (number of previous c/s, risk of accreta given a placenta previa)
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***1 –> 24%
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***2 –> 48%
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***3 –> 67%
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There will be a test question on prior c/s and placenta previa.
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===Operative Vaginal Delivery===
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*Forceps and vacuum can be used to guide the baby's head out of the pelvis.
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*There are many different types and procedures.
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====Operative Vaginal Delivery - Classification====
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*We want, first, to be sure the baby has reached the pelvic inlet.
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*Didn't talk about any of this:
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*Outlet: scalp visible at introitus w/out separating labia; no rotation
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*Low: leading point of skull at or below +2 cm station
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**Rotate < 45°
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**Rotate > 45°
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*Mid: above +2 cm station but engaged
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====Operative Vaginal Delivery - Indications====
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*Nonreassuring FHT’s
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*Prolonged 2nd stage of labor
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*Shortened 2nd stage if pushing / Valsalva not indicated
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*Maternal exhaustion
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====Operative Vaginal Delivery - Prerequisites====
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*Cervix completely dilated
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*Ruptured membranes
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*Fetal skull engaged in pelvis
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*Empty bladder
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*'''Position! Position! Position!'''
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**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.
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*Adequate pelvis
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*Adequate anesthesia
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====Operative Vaginal Delivery - Forceps Assisted====
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*Use the same angles when applying traction.
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*Apply the extension just like in a non-operative vaginal delivery.
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====Operative Vaginal Delivery - Risks====
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*Maternal:
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**Vaginal / perineal trauma, damage to rectal sphincter
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**Mostly forceps issues with mom
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*Fetal:
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**Mostly vacuum issues with baby
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**Cephalohematoma
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**Subgaleal hemorrhage
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**Bony facial trauma
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**Facial nerve injury
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**Intraventricular hemorrhage
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====Birth Trauma====
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*Caput succedaneum:
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**Very common
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**Crosses midline
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*Subgaleal hemorrhage:
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**Does not cross midline
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**Rare
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**Hypovolemia and DIC
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===Common Post Partum Problems===
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*PP Hemorrhage: >500cc (>1000cc for c/s):
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**Atony
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***When the uterus won't contract.
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***Linings aren't collapsed together to stop bleeding.
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**Lacerations (cervix, vagina, perineum)
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**Retained placenta
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***Keeps the endometrium layers from coapting (collapsing together).
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**Uterine rupture
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**Uterine inversion
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**Amniotic fluid embolism
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*Endometritis:
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**Fundal tenderness w/ temperature >38°C x 2 or >38.5°C
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**Polymicrobial infection
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**More common after c/s
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***Prolonged ruptured membranes
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***Chorioamnionitis
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**'''Treat with broad spectrum antibiotics'''
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====PP / Post-Op Fever====
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*Causes and symptoms
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**Wind (atelectasis, pneumonia)
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**Wound (seroma, necrotizing fasciitis)
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**Water (UTI)
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**Walk (thrmobophlebitis)
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**Wonder drug (drug reaction)
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**Womb (endometriosis)
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**Wean (mastitis, engorgement)
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Revision as of 16:43, 8 March 2012

DgI5m4 Appreciate you sharing, great article post.Much thanks again. Keep writing.

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