Normal Labor and Delivery(AFE)

Medvediev M.V., M.D., Ph.D.

Department Of Obstetrics & Gynecology

Dnepropetrovsk medical academy

Definitions

• Labor – Uterine contractions that result in effacement and dilatation of the cervix.
• Braxton-Hicks – Uterine contractions NOT associated with cervical change.
• Shorter in duration
• Less intense
• Over lower abdomen and groin
• Resolve with ambulation
• Lightening – Descent of the fetal head into the pelvis

Definitions

• Term delivery(labor): 37-42weeks
• pre-term delivery: 22-<37 weeks
• post-term delivery:≥ 42 weeks
• Abortion: <22 weeks
• 85% of women have spontaneous labor and delivery between 37-42 weeks
• LMP: last menstrual period
• EDC: expected date of confinememt

• What actually “triggers” the onset of labor?

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• Several maternal, fetal, and even placental factors probably interact to initiate the start of true labor contractions

There are several theories

• Mechanical - Uterine stretching? A weak theory because there is a wide variation of uterine size between different pregnancies in the same woman.

Hormonal theories

• 1. Oxytocin stimulation
• 2. Progesterone reduction
• 3. Estrogen stimulation
• 4. Increase fetal cortisol production
• 5. Increase in prostaglandin’s (theorized but not yet proven)

The four factors for labor

• Force (contraction)
• birth canal (bony canal)
• fetus (lie,position ,presentation,weight)
• psychical-factors

Mechanics of Labor

• The Powers
• Forces generated by uterine musculature
• Frequency, amplitude, and duration of ctx’s
• Observation, manual palpation, tocodynamometry, intrauterine pressure catheter (IUPC)
• Measured in Montevideo units
• Average strength of ctx’s (mmHG) x no. of ctx’s in 10 minutes
• Adequate 200-250 MVUs

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The contractions

• increase in frequency and duration
• uterus can be felt to harden during contraction
• lasting about 30-45 seconds
• interval between contractions to be 5 min’
• the pain of labor is a character

NST CST

Mechanics of Labor

• Passenger
• Fetal size
• Abdominal palpation or Ultrasound
• Macrosomia (>4500g) associated w/ failure to progress
• Lie
• Longitudinal axis of fetus relative to longitudinal axis of uterus
• Longitudinal, transverse or oblique
• Presentation
• Fetal part that directly overlies pelvic inlet
• Cephalic, breech, or shoulder
• Compound – presence of >1 fetal part overlying the pelvic inlet
• Funic – umbilical cord presenting at pelvic inlet
• Malpresentation – any presentation that is not cephalic with occiput leading

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Mechanics of Labor

• Passenger (cont)
• Attitude
• Position of head with regard to fetal spine (ie: degree of flexion or extension)
• Flexion allows smallest diameter of fetal head to present at pelvic inlet
• Position
• Relationship of a nominated site of presenting part to denominating location on internal pelvis
• Example: cephalic presentation

Mechanics of Labor

Mechanics of Labor

• Passenger (cont.)
• Station
• Measure of descent of presenting part of the fetus through the birth canal.
• Multifetal Pregnancy
• Increase probability of abnormal lie and malpresentation in labor

Mechanics of Labor

• Passenger (Leopold’s maneuvers)

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Orientation of Fetus

• Vertex, breech or transverse lie
• Palpate vaginally
• Leopold’s Maneuvers

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Bony pelvis

• The planes of pelvis
• inlet plane (promontory)
• mid plane of pelvis (ischial spines)
• outlet plane (two intersecting triangles)

Cardinal Movements of Labor

• Engagement
• Passage of widest diameter of presenting part to level below the plane of the pelvic inlet
• 0 station
• Occurs earlier in nulliparous women (36 wks)
• Descent
• Downward passage of presenting part through the pelvis.
• Flexion
• Occurs passively as the head descends due to the shape of the bony pelvis and resistance of pelvic floor soft tissues
• Allows smallest diameter of fetal head to pass through the pelvis.

Descent

• Fetal head descends through the birth canal
• Defined relative to the ischial spines
• 0 station = top of head at the spines (fully engaged)
• +2 station = 2 cm past (below) the ischial spines

Cardinal Movements of Labor

• Internal Rotation
• Rotation of presenting part from original position (transverse) to anteroposterior position
• Extension
• Occurs once fetus has descended to the level of the introitus
• Base of occiput in contact with inferior margin of symphysis pubis
• External Rotation
• Return of fetal head to correct anatomic position in relation to the fetal torso
• Expulsion
• Delivery of rest of fetus
• Anterior shoulder delivered first with rotation under the symphysis pubis

Cardinal Movements of Labor

Symptoms and signs of the onset of the labor

• Painful uterine contraction (at least 20 sec long 1 per 10 min.)
• a show
• effacement and dilation of the cervix
• rupture of membranes

The show

• The mucus plug is expelled from the cervix
• mixing with a little blood

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the rupture of the membranes

• at any time during labor

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effacement and dilation of the cervix

• to be short, taken up, dilated

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Stages of labor

• The first stage:
• onset of labor to full cervical dilation(10cm)
• the latent phase ( onest to <3cm, <16h)
• the active phase(>3cm to 10cm, <8h)
• The second stage:
• 10 cm to the delivery of the infant, <2h
• The third stage:
• delivery of the infant to delivery of the placenta, <30m’
• The fourth stage:
• 2 hours after delivery of the placenta

Latent Phase Labor

• <3-4 cm dilated
• Contractions may or may not be painful
• Dilate very slowly
• Can talk or laugh through contractions
• May last days or longer
• May be treated with sedation, hydration, ambulation, rest, or pitocin

Active Phase Labor

• At least 3-4 cm dilated
• Regular, frequent, usually painful contractions
• Dilate at least 1.2-1.5 cm/hr
• Are not comfortable with talking or laughing during their contractions

Management of normal labor

• The first stage:
• education, eating, voiding,
• position(sitting, reclining, recumbent)
• monitoring of the fetal heart rate ,
• dilation of cervix and frequency
• severity of uterus contractions (auscultation or electronic monitoring)

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Progress of Labor

• Lasts about 12-14 hours (first baby)
• Lasts about 6-8 hours (subsequent babies)
• Considerable variation.
• Effacement (thinning)
• Dilatation (opening)
• Descent (progress through the birth canal)

Cervix

• Dilatation: How far has the cervix opened (in cm)
• Effacement: How thin is the cervix (in cm or %)

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Status of Membranes

• Nitrazine paper turns blue in the presence of alkaline amniotic fluid (“nitrazine positive”)
• Vaginal secretions are nitrazine negative (yellow) because of their acidity
• Pooling of amniotic fluid in the vaginal vault is a reliable sign

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Monitor the Fetal Heart

• During early labor, for low risk patients, note the fetal heart rate every 1-2 hours.
• During active labor, evaluate the fetal heart every 30 minutes
• Normal FHR is 120-160 BPM
• Persistent tachycardia (>160) or bradycardia (<120, particularly <100) is of concern

Electronic Fetal Monitors

• Continuously records the instantaneous fetal heart rate and uterine contractions
• Patterns are of clinical significance.
• Use in high-risk patients.
• Use in low-risk patients optional

Normal Patterns

• Normal rate
• Short term variability (3-5 BPM)
• Long term variability (15 BPM above baseline, lasting 10-20 seconds or longer)
• Contractions every 2-3 minutes, lasting about 60 seconds

Tachycardia

• >170 BPM
• Most are not suggestive of fetal jeopardy
• Associated with:
• Fever, Chorioamnionitis
• Maternal hypothyroidism
• Drugs (tocolytics, etc.)
• Fetal hypoxia
• Fetal anemia
• Fetal arrythmia

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Bradycardia

• Sustained <110 BPM
• Most are caused by increased in vagal tone
• Mild bradycardia (80-90) with retention of variability is common during 2nd stage of labor
• <80 BPM with loss of BTBV may indicate fetal distress

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Late Decelerations

• Repetive, non-remediable slowings of the fetal heartbeat toward the end of the contraction cycle
• Reflect utero-placental insufficiency

Early Decelerations

• Periodic slowing of the FHR, synchronized with contractions
• Rarely more than 20-30 BPM below the baseline
• Innocent
• Associated with fetal head compression

Variable Decelerations

• Variable in onset, duration and depth
• May occur with contractions or between them
• Sudden onset/recovery
• Increased vagal tone, usually due to some degree of cord compression

Severe Variable Decelerations

• Below 60 BPM for at least 60 seconds
• If persistent, can be threatening to fetal well-being, with progressive acidosis

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Prolonged Decelerations

• Last > 60 seconds
• Occur in isolation
• Associated with:
• Maternal hypotension
• Epidural
• Paracervical block
• Tetanic contractions
• Umbilical cord prolapse

The second stage

• :--- < 2 hour
• fetal heart rate
• maternal conditions:
• pulse, blood pressure, respiratory rate ,
• temperature, urine output, fluid intake…
• evaluation of progress of labor
• cervical dilation, station, position of the
• presenting part, status of membranes,
• meconium, blood

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• Pushing:
• with the onset of each contraction, the mother is encouraged to inhale, hold her breath, and push
• increase in intra-abdominal pressure
• aiding in fetal descent through the birth canal.

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• Head visible on vulval gapping*
• Crowning of head*
• Laceration or Episiotomy
• Delivery of fetus
• Deal with umbilical cord

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Episiotomy

• Avoids lacerations
• Provides more room for obstetrical maneuvers
• Shortens the 2nd Stage Labor
• Midline associated with greater risk of rectal lacerations, but heals faster
• Many women don’t need them.

the third stage:�

• waiting for up to 30 min’
• the best option is active management
• the uterus decreases in size
• delivery of placenta(spontaneously, manually
• inspection of the birth canal
• evaluated for lacerations

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Two Methods of Third Stage Management

• Physiologic (“expectant”) management
• Oxytocics are not used
• Placenta is delivered by gravity and maternal effort
• Cord is clamped after delivery of the placenta
• Active Management
• Oxytocic is given
• Cord is clamped
• Placenta delivered by controlled cord traction (CCT) with counter-traction on the fundus
• Fundal massage

Critical Issues Pertaining to the Third Stage of Labor

• Active vs. physiologic management
• Theoretical potential risks of each
• Entrapment of placenta
• Avulsion of cord
• Uterine inversion
• Choice of oxytocic agent
• Stability, safety and side effects of oxytocics
• Unproven benefit of nipple stimulation
• CCT and fundal massage if no oxytocic available

Physiologic Management: Advantages and Disadvantages

• Advantages
• Does not interfere with normal labor process
• Does not require special drugs/supplies
• Disadvantages
• Increases length of third stage
• Increases risk of postpartum hemorrhage (PPH)

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Active Management: Advantages and Disadvantages

• Advantages
• Decreases length of third stage
• Decreases risk of PPH
• Disadvantages
• Requires oxytocics and items needed for injection
• Requires a birth attendant with skills in:
• Observation
• Giving an injection
• CCT

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Procedure for Active Management

• Oxytocin
• Within 1 minute of birth, palpate abdomen to rule out presence of another baby
• Give oxytocin
• CCT
• Await strong uterine contraction (2–3 minutes)
• Apply controlled cord traction while applying countertraction above pubic bone
• If placenta does not descend, stop traction and await next contraction

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The Bristol Trial: �Details of Active Management

• Try to give one ampule of oxytocic (5 units oxytocin and 0.5 mg ergometrine routinely or 10 units synthetic oxytocin if mother has high BP) immediately after delivery of anterior shoulder
• Try to clamp cord 30 seconds after delivery of baby
• When uterus has contracted, try to deliver placenta by CCT with protective hand on abdomen helping to shear off placenta and preventing uterine inversion
• Try not to give any special instructions about posture

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Prendiville et al 1988.

The Bristol Trial: �Details of Physiologic Management

• Try not to give oxytocic
• Try to leave cord attached to baby until placenta is delivered
• Try not to use CCT or any manual interference with uterus at fundus
• Try to encourage mother to concentrate on feeling for next contraction or urge to push
• When mother feels contraction or urge or there are signs of separation, encourage mother and help her change posture
• If placenta does not deliver spontaneously, wait, try putting baby to breast and encourage maternal effort

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Prendiville et al 1988.

Active vs. Physiologic Management: Postpartum Hemorrhage

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Prendiville et al 1988; Rogers et al 1998.

Active vs. Physiologic Management: Results

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Active vs. Physiologic Management: The Bristol and Hinchingbrooke Trials

• Conclusion: Active management of the third stage reduces the risk of PPH:
• Increased risk of PPH associated with physiologic management
• Increased need of blood transfusion associated with physiologic management
• Oxytocin was drug of choice for active management
• No increase in entrapment of placenta with active management

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Oxytocic Drugs

• Oxytocin- posterior pituitary extract
• Ergometrine- preparation of ergot
• Syntometrine- combination of oxytocin and ergometrine
• Misoprostol- prostaglandin E1 analogue

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Oxytocic Drugs: Oxytocin

• Advantages
• Causes uterus to contract
• Acts within 2.5 minutes when given IM
• Generally does not cause side effects
• Disadvantages
• More expensive than ergometrine
• IM or IV preparations only
• Not heat stable

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Oxytocic Drugs: Ergometrine

• Advantages
• Low price
• Effect lasts 2–4 hours
• Disadvantages
• Takes 6–7 minutes to become effective when given IM; oral form insufficiently effective
• Causes tonic uterine contraction
• Increased risk of hypertension, vomiting, headache
• Contraindicated in women with hypertension or heart disease
• Not heat stable

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Oxytocic Drugs: Syntometrine

• Advantages
• Combined effect of rapid action of oxytocin and sustained action of ergometrine
• Disadvantages
• Increased risk of hypertension, nausea and vomiting
• Not heat stable

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Oxytocin vs. Syntometrine: Objective and Design

• Objective: To compare effects of syntometrine with oxytocin in reducing the risk of PPH and other maternal and neonatal outcomes
• Design: Randomized controlled trials

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McDonald, Prendiville and Elbourne 2000.

Oxytocin vs. Syntometrine: Results

• Syntometrine was associated with a small reduction in risk of PPH < 1000 mL (OR 0.74, 95% CI 0.65-0.85)
• Adverse effects of vomiting and hypertension were associated with the use of syntometrine
• There were no differences in other maternal or neonatal outcomes

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McDonald, Prendiville and Elbourne 2000.

Oxytocin vs. Syntometrine: Conclusion

Need to weigh benefit of reduction in risk of PPH with risk of other adverse effects associated with syntometrine

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McDonald, Prendiville and Elbourne 2000.

Stability of Oxytocics in Tropical Climates: Objective and Design

• Objective:
• To determine pattern of stability in long term dark storage, short term exposure to high temperature and light
• To develop guidelines
• Methods: Tested field samples of ergometrine and methylergometrine and also simulated field storage conditions at different temperature/light exposure

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WHO 1993.

Stability of Oxytocics in Tropical Climates: Results

Field:

• Ergometrine: only 31% of samples had compliant level of active ingredient
• Oxytocin: one expired, 5 samples had 104–142% of stated amount of active ingredient

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WHO 1993.

Stability of Oxytocics in Tropical Climates: Results (continued)

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WHO 1993.

Stability of Oxytocics in Tropical Climates: Conclusions

• Stability of oxytocin is better than ergometrine/ methylergometrine, especially regarding light
• Store refrigerated, in dark, labeled
• Remove from box only for immediate use
• Short periods unrefrigerated are fine (1 month at 30°C, 2 weeks at 40°C)

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WHO 1993.

Nipple Stimulation

• Nipple stimulation has not been shown to reduce risk of PPH
• Randomized controlled trial of suckling immediately after birth with over 4,000 subjects in Malawi showed no significant difference in frequency of PPH, mean blood loss or retained placenta
• When oxytocics are not available, CCT and fundal massage should be performed
• Advantages of early breastfeeding and nipple stimulation:
• Stimulates natural production of oxytocin
• May maintain tone of contracted uterus
• Benefits baby

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Bullough, Msuku and Karonde 1989.

Recommendations Concerning Selection of Oxytocic

• Use oxytocin, when available:
• If oxytocin is not available, use syntometrine or ergometrine
• If oxytocic drugs are not available, use nipple stimulation
• Remember: Do not use ergometrine in women with hypertension or heart disease
• Store oxytocics in refrigerator (2–8ºC) and away from light
• Misoprostol rectally has advantages; awaiting confirmatory studies.

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Summary

• Active management of third stage includes:
• Oxytocin
• Controlled cord traction
• Fundal massage
• Ensuring supply of oxytocin is a priority
• Reduces risk of PPH
• Retained placenta
• Need for therapeutic oxytocics

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Placental Separation

• Signs of separation:
• Increased bleeding
• Lengthening of the cord
• Uterus rises, becoming globular instead of discoid
• Uterus enlarges, approaching the umbilicus
• Normally separates within a few minutes after delivery

Clamp and Cut the Cord

• Clamp about an inch from the baby’s abdomen
• Use any available instruments or usable material
• Check the cord for 3-vessels, 2 small arteries and one larger vein

Inspect the Placenta

• Make sure it is complete
• Look for missing pieces
• Look for malformations
• Look for areas of adherent blood clot

“The fourth stage”�

• postpartum uterine hemorrhage, 1%
• repeated uterus palpation through the abdominal wall
• the amount of blood on pads are monitored
• pulse and BP are monitored
• use of drug : oxytocin

Analgesia for Labour

1. Nonpharmacologic techniques
2. Parenteral narcotics
3. Inhalational gas
4. Regional techniques

Epidurals

Nerve blocks

Pain pathways & blocks during labour

LABOUR

• FIRST STAGE
• UP TO 10 CM (fully) DILATED
• PAIN FROM UTERINE CONTRACTION T10-L1
• TRANSITION
• 7-10 CM
• INC SOMATIC PAIN- VAGINAL DISTENTION
• SECOND STAGE
• SOMATIC PAIN (S2,3,4) PLUS
• RECTAL PRESSURE

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Epidural – Site of insertion

L3/4/5

Epidural Analgesia

Epidural Analgesia

Drugs used in Epidural Analgesia

Local Anaesthetics

Lidocaine, Bupivicaine, Levo-bupivicaine, Ropivicaine

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Narcotics/Opioids

Fentanyl, Morphine

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Effects dependent on volume and concentration

Epidural Analgesia

Contraindications

Absolute: 1. Allergy to local anaesthetics

2. Infection at intended puncture site

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Relative: 1. Hypovolaemia

2. Coagulopathy

3. Systemic sepsis

4. Progressive neurologic disease

5. Chronic low back pain.

Epidural Analgesia

Advantages

Avoids IV/IM narcotics

Patient awake/comfortable

May easily proceed to C/S

Disadvantages/Complications

Hypotension

Postdural puncture headache

Nerve damage

Chronic back ache

Total spinal

Intravascular injection

??? Retards labour

Test dose

Anaesthesia for Cesarean Section

1. Spinal
2. Epidural
3. General Anaesthesia

Spinal Anaesthesia

The Needles

Combined Spinal-Epidural anaesthesia

Drugs used in Spinal Anaesthesia

Local Anaesthetics

Lignocaine, Bupivicaine (Levo-bupivicaine, ropivicaine)

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Narcotics/Opioids

Fentanyl, Morphine

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Effects dependent on volume, concentration & baricity.

General Anaesthesia for Cesarean Section

Indications 1. Acute fetal distress

2. Regional anaesthesia refused, failed or C/I.

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Advantages 1. Rapid induction

2. Airway control

3. More ? Cardiac stability

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Disadvantages 1. Potential airway/intubation difficulties

2. Increased risk of aspiration.

3. Fetal depression from drugs.

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General Anaesthesia for Cesarean Section

General Anaesthesia for Cesarean Section

BE PREPARED !

General Anaesthesia for Cesarean Section

Rapid Sequence induction

1. 100% O₂ for at least 3 minutes.
2. Sleep dose of induction agent.
3. Cricoid pressure or Sellicks manoeuvre.
4. Suxamethonium.
5. Intubate with cuffed endotracheal tube.

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Cricothyroidotomy

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