Labor and Delivery

Question 1

Physiology of Labor

Progesterone/estrogen/hCG

Answer 1

Progesterone: function is to support/stabilize the endometrium in an environment that is conducive to fetal survival and to suppress contractility in uterine smooth muscle.

Estrogen: functions are to stimulate growth of the myometrium and antagonize the myometrial-suppressive activity of progesterone, also used to stimulate the development to the mammary glands.

Chorionic gonadotropins (b-hCG): produced by fetal trophoblast cells, binds to LH receptors on the cells of the corpus luteum, which prevents luteal regression, also is the signal for maternal recognition of pregnancy.

Question 2

Physiology of labor

Relaxin / Prolactin

Answer 2

Relaxin: Causes relaxation of pelvic ligaments, mostly at the end of gestation to prepare body for delivery.

Prolactin: stimulates the mammary gland development and milk production. Also provides positive feedback for when a woman is lactating to act as a somewhat natural form of birth control.

Question 3

Physiology of labot

Oxytocin

Answer 3

Peptide hormone synthesized by hypothalamus and released from posterior pituitary

Also produced by the placenta
Release of oxytocin > forceful contractions

Most potent endogenous uterotonic
Circulating levels of oxytocin don’t change during pregnancy, however myometrial receptor concentrations increase in pregnancy and in labor

Question 4

physiology of labor

prostagladins

Answer 4

Paracrine/autocrine hormones

Concentration of prostaglandins in amniotic fluid and maternal circulation are increased during parturition

Help in the onset of synchronous uterine contractions, cervical ripening, and increase myometrial sensitivity to oxytocin and increase oxytocin receptor concentrations

Question 5

Phases of Parturition (labor)

UTERINE QUIESCENCE

Answer 5

Makes up 95% of pregnancy
Uterine smooth muscle tranquility while maintaining cervical structure and integrity
Uterine size increases, uterine vascularity increases
Myometrial contractions which do not cause cervical change (braxton hicks)

Question 6

Phases of Parturition (labor)

CERVICAL SOFTENING

Answer 6

Cervix function in pregnancy:
1) Maintain barrier of lower vaginal tract and upper internal tract from infection
2) Maintain cervical competence despite increasing uterine size
Non pregnant women = cervix closed and firm
End of pregnancy = cervix distentable and soft
Tissue remodeling to soften the cervix
Increased vascularity, cellular hypertrophy, and collagen changes to alter strength and flexibility

Question 7

Phases of Parturition

PREPARATION FOR LABOR

Answer 7

Progression of uterine changes during the last 6-8 weeks (uterine activation)
Myometrium prepares for labor contractions
Oxytocin receptors and prostaglandin receptors increase
Cervical ripening (Additional cervical remodeling)

Question 8

Phases of Parturition

LABOR

Answer 8

Uterine contractions that cause cervical dilation and change
Contractions of sufficient frequency and intensity
Divided into three stages

Question 9

Braxton-Hicks Contractions

Answer 9

False labor pains
Do not cause cervix to dilate or efface
Usually irregular in duration and intensity (lasting < 30 seconds up to 2 minutes)
Described as strong menstrual cramps
Can start around 6 weeks of gestation, but usually are not felt until 2nd or 3rd trimester
Body’s way of preparing for labor
Can be caused by:
Increased physical activity, full bladder, dehydration, after intercourse, and near the end of pregnancy

Question 10

labor

When is Immediate Attention Needed?

Answer 10

Contractions becoming more frequent and intense (every 5 minutes or more, severe pain, not able to speak full sentences during contractions)
Vaginal bleeding
Leakage of fluid
Decreased fetal movement

Question 11

definition of labor

Answer 11

LABOR = Regular painful uterine contractions that cause cervical dilation and effacement

Question 12

cervical measurement

Answer 12

Cervical measurement =
Dilation / effacement / station

Question 13

Cardinal Movements of Labor

Answer 13

engagement
descent
flexion
internal rotation
extension
external rotation (restitution)
expulsion

Question 14

Types of pelvis

Question 15

stages of labor

Answer 15

First Stage: When labor begins until 10cm dilated

Latent Stage: Slow cervical change, usually less than 1cm an hour

Active Stage: Fast cervical change, starts about 5-6cm dilated and cervix opens 1cm/hr

Second Stage: 10cm dilated until fetus delivered

Third Stage: Baby delivered until placenta delivery

Question 16

First Stage of Labor: Latent vs Active Labor

Answer 16

LATENT
Mucus plug / Bloody show
Extrusion of mucus and blood that filled the cervical canal
Slow cervical dilation to 5cm dilated
Less than 1cm per hour
Painful irregular contractions

ACTIVE
Rapid cervical change
Painful regular contractions
Cervical dilation 1cm per hour
Spontaneous rupture of membranes

FIRST STAGE OVERALL
Nulliparous: Average 10-14hrs
Multiparous: Average 5-7hrs

Question 17

labor

Cervical Exam

Answer 17

Dilation
How open the cervix is related to the internal cervical os
Based on digital hand exam 0-10cm

Effacement
Percent of cervix shortened
Subjective based on examiner
Normal cervix about 4cm > 2cm felt = 50% effaced

Station
Relation of the fetal presenting part to the ischial spine (-5 to +5)
Most descended part of the fetus at ischial spine = 0 station

Question 18

Bishop Score

Answer 18

Effacement
Dilation
Station
Cervical position
In relation to the patient
Posterior / Mid position / Anterior
In labor the cervical position usually advances from posterior to anterior
Cervical consistency
Consistency of cervix- firm, medium, soft
In labor the cervix usually softens

**Bishop Score > 8 is consistent with a cervix which is favorable for vaginal delivery **

Question 19

Spontaneous Rupture of Membranes

Answer 19

SROM
Check the color
Clear/yellow - generally ok
Green - meconium = first bowel movement of fetus
Dark green and thick amniotic fluid can be a sign of distress from the baby
Red - blood-tinged could be mixed with blood from cervical stretching
Bright red blood could be a sign of placental abruption

Question 20

fetal head

Question 21

Fetal Orientation in Utero

Answer 21

Lie: relationship between longitudinal axis of baby with respect to uterus and patients body
Longitudinal, transverse, oblique

Presentation: Fetal presenting part in the pelvis
Cephalic, breech, compound

Position: Relationship and orientation of the presenting fetal part in the pelvis
LOA / ROA / LOP / ROP / LOT /ROT

Question 22

Fetal Position

Answer 22

Breech
Transverse
Vertex

Leopold’s Maneuver
4 distinct maneuvers to palpate the maternal abdomen and determine fetal position and size

Question 23

fetal positions

breech

Answer 23

Buttocks or lower extremities presenting part
3-4% term pregnancies
Frank
Flexing both hips and legs straight near face (Frank = Face)
Complete Breech
Fetus sitting in flexion both hips, both legs flexed (tucked)
Incomplete Breech
Combination of one or both hips extended
Footling - one leg extended
Double footling - both legs extended

Question 24

Second Stage of Labor

Answer 24

10cm dilated (fully dilated) until baby is born!

Question 25

Third Stage of Labor

Answer 25

Fetus delivered until placenta is delivered

Question 26

Delivery of Fetus & Placenta

Answer 26

Fetal head restitution
Check for nuchal cord
Deliver anterior shoulder with gentle traction
Guide fetus posterior&raquo_space; anterior

PLACENTA
Up to a 30-minute delay in delivery of placenta is normal
Signs of placental separation:
Fresh show of blood
Lengthening of umbilical cord
Uterus becomes firm and globular

Question 27

Management of 1st Stage of Labor

Answer 27

Intrapartum fetal monitoring
Maternal vital signs

Subsequent cervical exams
Latent phase every 4-8hrs / Active phase every 1-2 hrs
1cm 1 finger tightly
3cm 2 fingers tightly
4cm 2 loose fingers
10 cm fully dilated, no cervix in front of baby’s head

IV fluids/ PO hydration
Maternal rupture of membranes
AROM/ amniotomy

Question 28

Management of 2nd Stage of Labor

Answer 28

Bear down/ pushing techniques
Push during uterine contractions
Knee and hip flexion
Fetal head descends through pelvis, rests on the perineum at the vaginal opening, bulging and the skin is stretched (crowning)

Question 29

Shoulder Dystocia

Answer 29

Impaction of the shoulder against pubic symphysis

Risk factors: fetal macrosomia, DM, prior hx, maternal obesity, post-term, prolonged 2nd stage

Fetal complications: frx of humerus & clavicle, brachial plexus injury (Erb’s palsy), hypoxic brain injury & death

Diagnosis: When routine maneuvers fail to deliver the infant
If risk factors present → should be anticipated & prepared for
Dorsal Lithotomy position (laying flat opens the pelvic space) with hips at a 90 deg angle
Turtle sign: incomplete delivery of head or chin tucking against maternal perineum

Question 30

Shoulder dystocia

Tx

Answer 30

Treatment:
McRoberts maneuver: sharp flexion of maternal hips to ↓ the inclination of the pelvis
Suprapubic pressure:at an oblique angle to dislodge the anterior shoulder
Rubin maneuver: pressure on accessible shoulder to push it toward fetal anterior chest wall
Wood corkscrew maneuver: pressure behind posterior shoulder to rotate infant & dislodge the anterior shoulder
Delivery of posterior arm/shoulder

If undelivered may need to fracture clavicle or cut maternal pubic symphysis or do Zavanelli maneuver (put head back in pelvis & perform CS)

Question 31

Erb’s Palsy

Question 32

Perineal Lacerations

Answer 32

1st degree: injury involving vaginal epithelium and vulva skin only

2nd degree: injury to perianal muscles, but not the anal sphincter

3rd degree: injury to perineum involving the anal sphincter complex

4th degree: injury to perineum involving the anal sphincter complex and rectal mucosa

Question 33

APGAR SCORE

Answer 33

Test performed on baby 1 to 5 minutes after birth- in rare cases it can also be done 10 minutes after birth

Tests: Heart rate, lung maturity, muscle tone and movement, skin color/oxygenation, reflex responses

All categories range from 0-2 (APGAR score of 10 being the highest!)

0-6 points = distress & 7-10 points = normal

Question 34

Labor Augmentation

Answer 34

Use of oxytocin and/or amniotomy to stimulate uterine contractions if adequate cervical changes do not occur with spontaneous labor

Amniotomy:
Artificial rupture of membranes (AROM)
Healthcare provider breaks water bag for patient
Helps with active management of labor
Releases prostaglandins, can cause an increase in uterine contractions and fetal head descent
Risks: Cord prolapse, infections
Contraindications: Malpresentation, maternal infections, fetal head station too high

Oxytocin
Natural oxytocin is a polypeptide hormone produced by the hypothalamus and secreted from posterior pituitary
Pitocin = synthetic drug form
Dose ranges from 2-40 mU/min
Uterus contracts in response to high levels of oxytocin
Pitocin can be given to patients to increase frequency and strength of contractions in labor

Question 35

Labor Induction

Answer 35

Cervical Ripening
Mechanical: Intracervical balloon
Medical: Prostaglandins
Misoprostol (cytotec): Synthetic Prostaglandin E analog
25mcg tablet placed into the posterior vaginal fornix at base of cervix
Causes cervical softening and ripening, also may induce some uterine contractions
Start oxytocin induction (earliest) 4hrs after initial insertion
Dinoprostone (cervidil)
10mg vaginal insert, sustained release lasts 12hrs
Start oxytocin induction 30-60 minutes after removal

Amniotomy
Oxytocin

Question 36

Operative Vaginal Delivery

Answer 36

Use of a device to help guide fetus out of the vaginal canal and achieve vaginal delivery

Benefits: Can perform quickly if fetal distress, avoid cesarean section
Risks: Maternal perineal and vaginal lacerations, potential newborn injuries (nerve palsy, skull fracture, intracranial hematoma)
Indications: Prolonged second stage of labor (N >3-4hrs pushing, M >2-3hr pushing). It also shortens second pushing stage of labor (for maternal benefit)
Contraindications: Fetal head not engaged in pelvis, fetal bone disorders

Forceps OR Vacuum

Question 37

Rupture of Membranes

Answer 37

Amniotic water sac breaking
Can occur before the onset of labor or throughout the labor process

PROM = Prelabor rupture of membranes
Rupture of fetal amniotic membranes after 37 weeks (full term) and prior to the onset of labor
8-10% pregnancies

PPROM = Preterm prelabor rupture of membranes
Rupture of fetal amniotic membranes before 37 weeks (preterm) and prior to the onset of labor
2-4% of pregnancies

SROM = Spontaneous rupture of membranes
Rupture of fetal membranes after 37 weeks (full term) and during labor

AROM = Assisted/Artificial rupture of membranes
Amniotic fluid sac is ruptured by a medical provider during labor induction/ augmentation

Question 38

PROM/PPROM- Risk Factors

Answer 38

MATERNAL FACTORS:
Preterm prelabor rupture of membranes (PPROM) in a prior pregnancy (recurrence risk is 16%–32% as compared with 4% in women with a prior uncomplicated term delivery)
Antepartum vaginal bleeding
Chronic steroid therapy
Collagen vascular disorders (such as Ehlers-Danlos syndrome, systemic lupus erythematosus)
Direct abdominal trauma
Preterm labor
Cigarette smoking
Illicit drugs (cocaine)
Anemia
Low body mass index (BMI < 19.8 kg/m2)
Nutritional deficiencies of copper and ascorbic acid
Low socioeconomic status

UTEROPLACENTAL FACTORS
Uterine anomalies (such as uterine septum)
Placental abruption (may account for 10%–15% of preterm PROM)
Advanced cervical dilatation (cervical insufficiency)
Prior cervical conization
Cervical shortening in the 2nd trimester (< 2.5 cm)
Uterine overdistention (polyhydramnios, multiple pregnancy)
Intra-amniotic infection (chorioamnionitis)
Multiple bimanual vaginal examinations (but not sterile speculum or transvaginal ultrasound examinations)

FETAL FACTORS
Multiple pregnancy (preterm PROM complicates 7%–10% of twin pregnancies)

Question 39

ROM- Diagnostic Evaluation

Answer 39

Evaluation:
Perform sterile speculum exam
Always perform sterile speculum exam (SSE) before doing a manual exam- if that patient’s water is broke you want to limit the amount of manual exams to reduce risk of infection!

Diagnostic Criteria:
Pooling: Copious fluid visualized in the posterior fornix of vaginal vault or leaking from the cervical os on examination
Ferning: Swab the fluid cells and visualize under microscope. The cells crystalize into a ferning shape, this confirms diagnosis.
Nitrazine/Amnisure: Tests the pH level of fluid, which is more alkaline than the acidic vagina. If it turns blue this is a positive rest. However other fluids which are alkaline result in false positive including blood, semen, and cervical mucus.

Ultrasound: Helpful for diagnosis but not a true diagnostic test. Evaluate 4 quadrants and measure AFI. If the patient had low fluid, this may be an indicator that pt is ruptured
When you are more advanced in cervical examinations, sometimes you can feel a “rubbery” “balloon-like” forebag which is amniotic sac or fetal scalp/hair- also helps tell if a patient is ruptured

Question 40

Answer 40

Question 41

PROM/ PPROM- Management

Answer 41

Patient is less than 34 weeks gestation
Admit to the hospital for surveillance
7 day course of antibiotics
Pelvic rest (not bed rest)
Steroids for fetal lung maturity
Patient is greater than 34 weeks gestation
Induction of labor
Group B strep prophylaxis while intrapartum

Always surveillance for: signs of infection- maternal fever, leukocytosis, maternal or fetal tachycardia, flank pain, vaginal discharge, bleeding, uterine pain

Risk of infection increases with >18hrs ROM

Question 42

Question 43

Group B Strep
Prophylaxis

Answer 43

During prenatal care, test all women at 35-36 weeks
Test vaginal/rectal bacterial culture swab to check for group B strep colonization
If positive > administer antibiotics during labor

BUT WHAT HAPPENS BEFORE 36 WEEKS??

Prophylaxis:
Penicillin G 5 million units IV loading dose then 2.5 million units IV every 4 hours
OR > Ampicillin 2g bolus then 1 g q 4 hrs
Low risk PCN allergy:
Ancef 2g loading dose then 1g IV every 8h
High risk PCN allergy:
Clinda/Erythro sensitive: Clindamycin 900mg IV q8h
Clinda/Erythro resistant: Vancomycin 1g IV q8h

Question 44

Cord Prolapse

Answer 44

When the umbilical cord prolapses through the cervix
True obstetric emergency, cord compression leads to fetal compromise/death
Risk factors include prematurity, abnormal presentation, multiparity, placenta previa, polyhydramnios, multifetal pregnancy, PROM, iatrogenic (amniotomy, ECV)
Treatment: pelvic exam to elevate presenting part, stat C/S!

Question 45

Chorioamnionitis

Answer 45

AKA Intraamniotic Infection (IAI)
1-4% of births in USA are complicated by intraamniotic infections
Neonatal sepsis can be reduced up to 80% with administration of intrapartum antibiotics

Question 46

IAI - Diagnosis

Answer 46

*Presumptive diagnosis =
*Fever >39.0 once, or >38.0 twice, 30 min apart.
*Plus one or more of; fetal tachycardia (>160bpm for >10min), maternal leukocytosis (>15,000mm), uterine fundal tenderness, and/or purulence from cervical os on SSE

*Clinical Diagnosis
*All the above + evaluation of amniotic fluid including, positive gram stain, low glucose level, positive fluid culture, elevated WBC, or histopathologic evidence of infection or inflammation in the placenta, fetal membranes, or umbilical cord

Question 47

IAI - Treatment

Answer 47

*Intrapartum regimen —
*Ampicillin 2 g intravenously every six hours plus
*Gentamicin 5 mg/kg intravenously once daily

If they have a Cesarean delivery — add anaerobic coverage
*Either metronidazole 500 mg orally or intravenously or clindamycin 900 mg intravenously every eight hours
*Add azithromycin 500 mg intravenously once

May continue treatment for 24-48hrs after delivery, depending on clinical scenario