Labor Flashcards
Phase 1 Parturition
Quiescence
- contractile unresponsiveness
- cervical softening
Phase 2 Parturition
Activation
- Uterine preparedness for labor
- Cervical Ripening
Phase 3 Parturition
Stimulation
- uterine contraction
- cervical dilation
- Fetal and placenta expulsion
Phase 4 parturition
Involution
- uterine involution
- cervical repair
- breastfeeding
Three Stages of Labor
First Stage = closed to 10 cm
Second Stage = 10 cm to delivery of the fetus
Third Stage = delivery of fetus to delivery of placenta
Cardinal Movements of Labor
- Engagement
- Descent
- Flexion
- Internal Rotation
- Extension
- External Rotation
- Expulsion
Classic female pelvic shape
Most Common
Gynecoid
A/P triangles are roughly even
Excellent candidate for NSVD
Least favorable pelvic shape for vaginal delivery
Android
Anterior triangle much bigger, heart shaped, prominent Sacrosciatic notch
Highly associated with arrest of first stage
Head difficult to get into pelvis
Pelvic shape associated with OP position
Anthropoid
15%
Anterior triangle bigger than posterior, narrow AP diameter
Associated with arrest in first or second stage
Least common pelvic shape
Associated with transverse arrest
Platypelloid Pelvis
A/P triangles are equal, but short AP diameter
Wide transverse axis of the pelvic inlet readily accommodates the occipitofrontal diameter of the fetal head as it descends in the pelvis - results in OT position
Pinard Maneuver - Breech extraction
Delivery of fetal legs
Two fingers are used to palpate down the fetal thigh until the knee is felt and flexed. The thigh is then moved away from midline after knee flexion is performed. Traction is then employed to deliver the foot
Loveset Maneuver Breech Extraction
Resolution of Nuchal Arm
Identify the anterior fetal arm and then gently flex the fetal elbow and attempt to sweep the arm down past the fetal face and out
Prague Maneuver Breech Extraction
Support shoulders and legs for flexion and subsequent delivery of fetal head
Two fingers of one hand support the shoulders of the fetus from underneath the fetus, while the other hand brings the fetal legs above and over the maternal abdomen.
Mauriceau-Smellie-Veit Maneuver Breech Extraction
Maxilla for flexion of fetal head
The index and middle fingers are applied to the fetal maxillae in order to flex the head during a breech delivery
Incidence of PPH for vaginal delvieries?
4%
Incidence of PPH for C/S?
6%
Timeframe for delayed PPH?
24H to 12 weeks postpartum
FHT w/ narcotics?
Decrease in accelerations
Decrease in variability
(should return to normal after 1-2 hours)
Adequate uterine contraction pattern for CST?
3 contractions in 10 minutes lasting AT LEAST 40 seconds each
Define Positive CST
Late decelerations after 50% or more of contractions (even if the contraction frequency is fewer than 3 in 10 minutes
Define Negative CST
No late or significant variable decelerations
Define Equivocal-Suspicious CST
Intermittent late decelerations or significant variable decelerations
Define Equivocal CST
Fetal heart rate decelerations that occur in the presence of contractions more frequent than every 2 minutes or lasting longer than 90 seconds
Define Unsatisfactory CST
Fewer than 3 contractions in 10 minutes or an uninterpretable tracing
Incidence of SD overall?
1.4%
Incidence of SD in pregnancies NOT affected by diabetes, but with birth weight > 4,500 g?
9-24%
Incidence of SD in pregnancies w/ diabetes + birth weight > 4,500 g?
20-50%
At what gestational age do you need 15x15 for NST?
32 weeks
Does an NST have a high or low negative predictive value?
HIGH!
Negative = no evidence of compromise
Reassuring that there is a high negative predictive value meaning low chance of disease in the fetus
Poor positive predictive value meaning even with decels, etc we don’t really know what is going on with the fetus
Components of BPP
30 mins, 10 pts (2 pts each)
- NST
- Fetal Movement (3 body or limb movements)
- Fine tone (1 episode of extension/flexion of extremity or open/close of hands)
- Breathing (1 episode of 30 seconds)
- Fluid (2x2 pocket, AFI >/= 5)
What is an equivocal BPP?
6/10
- If >/= 37w0d, consider delivery
- If < 37w, repeat BPP in 24 hours
- If repeat test = 6, delivery
- If repeat test > 6, observe and repeat per protocol
4/10 BPP?
- Typically deliver
- If same day repeat test is = 6, deliver
- If < 32w0d, additional monitoring may be appropriate
0-2/10 BPP?
- Delivery
- If delivery is not planned antenatal testing should not be performed because results will not inform management
In what order do BPP components develop? And at what gestation?
- fluid (early)
- fine tone (8wks)
- Gross movement (9 wks)
- Breathing (21 wks)
- FHT reactivity (26- 32 wks)
Loss of components is OPPOSITE of development (FHT reactivity and breathing are first to go), fluid is last
What parameter of a BPP can be BEST used to evaluate uteroplacental function?
AFI
- reflects fetal urine production, which if decreased is due to lack of renal perfusion which can be caused by placental dysfunction
Components of a modified BPP?
NST + Amniotic fluid assessment
Prolonged second stage for nulliparous
3 hr
No longer dependent on epidural status
Prolonged second stage for multiparous
2 hrs
No longer dependent on epidural
GA needed for Vacuum?
34 weeks
- less than 34w has increased risk of cephalohematoma, retinal hemorrhage, and intracranial hemorrhage
Rotation degree with Forceps?
Can rotate fetal 45 degrees of less
Differentiate outlet, low and mid forceps
OUTLET= fetal scalp visible at introits, rotation does not exceed 45 degrees
LOW = fetal skull at 2 station or more and not on the pelvic floor
rotation of 45 degrees or less = w/ out rotation
rotation greater than 45 degrees = w/ rotation
MID = station is above 2+ cm, but head is engaged
Increased risk of 3/4th degree tears w/ vacuum?
2x the risk compared with SVD
Increased risk of 3/4th degree tears w/ forceps?
6x the risk compared with SVD
Risks of using combination vacuum + forceps?
- increased anal sphincter injuries compared to either one alone
- increased intracranial hemorrhage (subdural, cerebral, subarachnoid) compared to either one alone
Compared to vacuum alone:
- increased facial nerve injury
- increased brachial plexus injury
- anal sphincter tears
- Low UA pH
Indications for operative vaginal delivery
- Prolonged second stage
- Suspicion of immediate or potential fetal compromise
- Shorten of the second stage of labor for maternal benefit
Correct vacuum placement?
2 cm anterior to the posterior fontanelle, overlaying the sagittal suture, ensuring that no maternal tissue is included
Contraindications to operative delivery?
- fetal head is unengaged
- position is unknown
- bone demineralization condition (osteogenesis imperfecta)
- Bleeding disorder (alloimmune thrombocytopenia, hemophilia, vWD)
Delivery for mentum anterior position?
Vag delivery
diameter of fetal had is small enough to allow for vaginal delivery
Delivery for mentum posterior position?
C/S
Risk factors for face presentation?
Prematurity
Fetal Wt < 2,500 g
Fetal Macroscomia
Anencephaly
High parity
3 muscles that make up the Levator Ani?
puborectalis
pubococcygeus
iliococcygeus
What muscle is responsible for controlling anal continence?
external anal sphincter
Components of APGAR scoring
Does the APGAR score predict individual neonatal mortality or neurologic outcomes?
No! And should not be used for that purpose.
When a newborn has an Apgar score of 5 or less at 5 minutes, umbilical artery blood gas from a clamped section of umbilical cord should be obtained. Submitting the placenta for pathologic examination may be valuable
A low 5-minute Apgar score (< 5) clearly confers an increased relative risk of cerebral palsy, reported to be as high as 20-fold to 100-fold over that of infants with a 5-minute Apgar score of 7–10
4 Criteria to diagnose HIE?
- Apgar score of less than 5 at 5 and 10 minutes after birth
- Fetal umbilical artery acidemia
- Multisystem organ failure
- Development of spastic quadriplegia or dyskinetic cerebral palsy
(Note that seizures are not included in this!) Neonatal seizures may occur after a hypoxic event, but there may be other causes of the seizures. Multisystem involvement includes renal, GI, cardiac, and hepatic injuries
Define Macrosomia, what is the increased risk of shoulder dystocia?
An estimated fetal weight of greater than 4,000–4,500 g at any gestational age is consistent with a diagnosis of macrosomia.
- Macrosomia corresponds to an estimated fetal weight greater than an absolute value (4,000–4,500 g)
- Large for gestational age (LGA) corresponds to a birth weight ≥90th percentile for that gestational age
Overall, shoulder dystocia occurs in 0.2–3% of vaginal deliveries, but the risk increases to 9–14% with a birth weight >4,500 g.
Base excess must be what for a diagnosis of neonatal encphalopathy?
Base excess must be >/= 12 mmol/L
Must be >/= 17 mmol/L for the neonate to qualify for hypothermia therpay
Umbilical Cord Gases
Low pH
High PCO2
Normal to slightly increased base deficit
Respiratory Acidosis
Umbilical Cord Gas
Low pH
Base Deficit > 12 mmol/L
Metabolic acidosis
Diagnosis of Triple I
Maternal Fever > 39C
OR
Maternal Fever 38.0-38.9 C + Clinical Feature (don’t need fever twice 30 mins apart anymore!)
Clinical Features:
- Maternal Leukocytosis (> 15K)
- Fetal Tachycardia
- Foul Discharge
Postpartum Treatment of Triple I?
Post C/S = 1 additional dose of chosen regimen
Post Vag: No additional doses required
Treatment for Triple I intrapartum?
Ampicillin 2g Q6h
Gentamicin 5 mg/kg IV Q24h
Most likely causitive agent in Triple I?
Polymicrobial (aerobic + anaerobic bacteria)
Usually ascending bacterial invasion from lower genital tract
Rare to have hematoenous spread secondary to Listeria
Define prolonged second stage
> 3 hours for nulliparous
2 hours for multip
**EPIDURAL STATUS NO LONGER CONSIDERED
What muscles are cut during episiotomy?
- Superficial Transverse Perineal
- Bulbocavernosus Muscle
- Deep Transverse Perineal
Indications for IUPC
Inadequate response to oxytocin
Absence of 1:1 nursing
Obesity
Adequate MVUs?
200 MVUs
Summation of the amplitude above baseline of all contractions in a 10 minute period
Requirements for operative vaginal delivery
Fetal head is engaged = largest diameter of the presenting part is at or below the level of the ischial spines
Cervix is fully dilated
Membranes ruptured
Indications for operative vaginal delivery
Prolonged second stage of labor
Suspected impending fetal compromise
Shorten 2nd stage for maternal indication
Contra-indications for operative vaginal delivery
Fetal head unengaged
Unknown position of fetal head
Fetal Conditions (bleeding disorder, bone demineralization disorder)
No facility/staff for Emergency Cesarean
Gestational Age < 34 weeks (Vacuum)
Prerequisites for Assisted Vaginal Delivery
Informed consent
Head engaged
Known position
- Station → z axis
- Position
- Attitude → Y axis, is the head flexed or extended (nose up in the air with attitude)
- Synclitism → X axis, is the midline sagittal suture off to the left or right?
Adequate anesthesia
Empty bladder and rectum
OUTLET Forceps
- Scalp visible at introitus without separating labia
- Fetal skull at pelvic floor (+2 or +3 station), caput doesn’t count!
- Fetal head is at or on perineum
- Head in OA or OP position with rotation not exceeding 45 degrees
*Forceps more likely to result in vaginal delivery compared to vacuum, but increased risk of 3-4th degree perineal lacerations
LOW Forceps
- Vertex higher than for outlet foceps, but below + 2 station
- Fetal skull at >/= + 2 station
- Fetal head is NOT at perineum
- OP or OA position, rotation < 45 degrees
**Do not do MID forceps
Counseling on fetal risks of operative vaginal delivery
- Scalp or face laceration
- Cephalohematoma
- Retinal hemorrhage (most common 38% w/ VAVD)
- Subgaleal hematoma
- Intracranial hemorrhage
- With forceps: facial lacerations, facial nerve palsy, skull fracture
Counseling on maternal risks of operative vaginal delivery
- Obstetrical laceration
- Pelvic hematoma
Incidence of retinal hemorrhage with VAVD?
38%
Only seen on fundoscopic exam of newborn
Often resolve, without clinical sequalae
Can also occur with spontaneous vaginal deliveries
Should you do forceps on a failed VAVD?
NO!!
Avoid, unacceptably high risk of fetal injury
Antibiotics if doing operative vaginal delivery?
If episiotomy or 3rd/4th degree laceration
Consider single dose of 2nd generation cephalosporin (cefoxitin, cefotetan)
Define macrosomia
absolute value
>/= 4,500 g
Define LGA
“relative value”
weight relative to gestational age
> 90%ile for any gestational age
Risk of shoulder dystocia with diabetes and macrosomia
25%
Risk of shoulder dystocia with and without macrosomia
Without 1.5%
With Macrosomia 15%
*but we are useless at predicting!
Risk of brachial plexus injury with shoulder dystocia?
Without macrosomia 0.1%
With macrosomia 5%
Only 10% of brachial plexus injuries are permanent
What interventions can reduce risk of macrosomia?
Exercise in pregnancy
Low Glycemic diet with GDM
Pre-pregnancy bariatric surgery w/ Class 2-3 obesity
Risk factors for macrosomia?
Hx of macrosomia
Obesity
Excessive weight gain
Gestational age > 40 weeks
GDM
Positive 1 hour and negative 3 hour GTT
When is Macrosomia an indication for CS?
EFW >/= 5000 g (4,500 in diabetic)
Cesarean Under Local
Extreme emergency
No skill anesthetist
Consent
Monitor EKG/ IO2 continuously
DOSING 7 mg/kg 0.5% WITH Epi
Maximum dose is 500 mg (100 cc)
OR
Mix 50 cc normal saline w/ 50 cc 1% lidocaine w/ EPI
Use all 100 cc
Inject along skin incision line
Then recuts sheath as abdomen is open
Then pour remainder into peritoneal cavity
Do not manipulate bowel, do not pack gutters, do not exteriorize uterus
SE in order of increasing toxicity:
*Always avoid intravascular injection
- metallic taste, peri-oral numbness
- Tinnitus
- Slurred speech/vision
- Altered consciousness
- Convulsions
- Cardiac arrhythmias
- Cardiac arrest
Contraindications to TOLAC?
- Previous uterine rupture
- Previously classical or T’d incision
- Extensive transfundal surgery
Who are candidates for TOLAC?
- 1 or 2 prior LTCS
- Previous low vertical CD
- Previous CD for unknown scar
- Twin gestation
What increases your chances of successful TOLAC?
- Do calculator!
- Prior vaginal birth
- Spontaneous labor
- If previous CD not due to arrest of labor
Who needs PCN ppx for GBS?
- Positive screen (36-38 wks)
- Bacteriuria in the pregnancy
- Previously affected infant
Which patient’s need PCN ppx with UNKNOWN GBS status?
< 37 weeks OR if > 37 weeks AND
- ROM >/= 18 hours
- Intrapartum fever
- Intrapartum GBS testing positive
- GBS positive in previous pregnancy
What to do if pt is GBS unknown and in PTL?
- Obtain swab, start PCN
- If culture returns negative, stop abs
- If labor fails to progress, discontinue ppx and obtain culture results for use when labor commences
What to do if pt is GBS unknown with PPROM?
- Obtain swab, start latency abs (includes GBS coverage)
- If pt is in labor continue abs until delivery
- If no labor, continue latency abs for 7 days, then base treatment on GBS culture results
What symptoms are considered high risk PCN allergy?
Hypotension
Angioedema
Respiratory distress
Options for GBS PPx in low risk PCN allergy?
Cefazolin 2 g IV initial dose, then 1 g Q8h until delivery
Options for GBS PPx in high risk PCN allergy?
If susceptible: Clindamycin 900 mg IV Q8h
If resistant: Vancomycin wt based dosing (20 mg/kg) IV Q8 hours
Weight that 3 g Cefazolin indicated at time of cesarean?
Wt > 120 kg
When is Azithromycin indicated for C/S?
If ruptured give 500 mg IV for ROM
