2nd Stage of Labor

Question 1

Define second stage of labor

Answer 1

• Anatomically - beginning with complete dilation of the cervix (10 cm) and ending with expulsion of the fetus
• Physiologically - beginning at the onset of the urge to bear down until the birth of the infant.
  
  • When the vertex or presenting part of the fetus has descended to a station (typically at +1) wherein an involuntary urge to bear down occurs

Question 2

Identify the average length and limits of normal of the second stage for both a primigravida and multipara, according to Friedman versus current evidence.

Answer 2

Friedman: (55% of labors with forceps)

• Average length
  
  • Nulliparous - 46 minutes
  • Multiparous - 14 minutes
• Limits of normal
  
  • Nulliparous - 2 hours
  • Multiparous - 1 hour

Current evidence:

• Average length (source: Gabbe)
  
  • Nulliparous
    
    • No epidural: 36 - 57 minutes
    • Epidural: 79 minutes
  • Multiparous
    
    • No epidural: 17-19 minutes
    • Epidural: 45 min
• Limits of normal (controversal)
  
  • Multiparous 2 - 3 hours (without vs with epidural)
  • Nulliparous 3 - 4 hours (without vs with epidural)

Question 3

Discuss timing and techniques of second stage pushing

Answer 3

• Passive descent (laboring down) - with epidural
  
  • Baby descends from force from contractions alone until urge to push, +1 station, or after 1-2hrs.
  • Aimed to reduce instrumental births & enhance maternal pushing efforts
  • Controversial - may help a little but may also be associated with adverse events → consider on an individual basis
    
    • Contraindications: Intra-amniotic infection, NRFHR, vaginal bleeding, or other clinical indications for expediting birth
• Open (grunting) vs closed (valsalva) glottis techniques:
  
  • Closed glottis contraindicated
    
    • Increases intrathoracic pressure due to breath holding
    • Associated with FHR decelerations, perineal trauma (lacerations, episiotomy), maternal exhaustion; and an increased risk for cystocele and urinary stress incontinence.
• Spontaneous versus directed pushing
  
  • Spontaneous - aka physiologic/supportive pushing
    
    • In response to natural urges, does not hold breath, often makes low grunting noise
    • Usually results in 5–6 bearing-down efforts per contraction of 3–10 seconds
    • Gaps in literature but no evidence against it
  • Directed - aka valsalva/authoritative
    
    • Begins when patient is found to be 10 cm
    • Instructions from a healthcare provider about when and how long to bear down.
    • Usually results in 3 pushes per contraction of 8–10 seconds each
    • Pushing occurs while the patient holds her breath. Silence is encouraged. Often results in a Valsalva maneuver.

*

Question 4

Describe birthing positions and discuss factors that influence choice

Answer 4

• Can push in any position: side, hands and knees, kneeling, standing, or squatting.
• Side-lying and semi-upright positions → less tears
• Pushing in upright positions
  
  • Small reduction in duration of 2nd stage labor, fewer episiotomies/assisted deliveries, and fewer abnormal FHR patterns
  • Possible increase in 2° perineal tears and an increase in maternal blood loss greater than 500 mL
• Supine and lithotomy positions associated w/ uterine pressure on the vena cava, maternal hypotension, decreased uterine perfusion, and variant FHR patterns
  
  • Lithotomy - associated with more perineal tears
• Changing positions frequently promotes changes in pelvic diameters → could aid the fetus finding the “best fit” during cardinal movements.
• Squatting increases the area within the pelvic outlet by approximately 20%
  
  • Can be most beneficial in the final phase of 2nd stage labor when the fetal presenting part is in the plane of the outlet
• Baby in OP position → #1: Hands & knees, w/ rounded back, Lunging, asymmetric kneeling, walking or side lying, Mexican rebozo technique, digital or manual rotation

Question 5

Select comfort measures or the appropriate anesthetic, if any, for the parturient in 2nd stage

Answer 5

• Non-pharm/Midwifery Model:
  
  • Intradermal sterile water
  • Hydrotherapy - -tub or shower
  • Acupuncture & massage
  • Relaxation techniques: breathing techniques, lamaze, hypnobirthing, aromatherapy
  • Positioning: birth ball
  • Cool/hot packs
  • Doula/continous labor support
  • Comfort care: Promote safe, private & calm environment, rest, relaxation, nutrition (if needed) & hydration. Oral care, clean & dry perineum & linens
  • Words of encouragement
  • TENS unit
  • Music/audiovisual
• Anesthetic/Pharm:
  
  • Pudendal block
    
    • Contraindications: coag disorder, infection in vagina, allergy
    • Place at ischial spines to block S2-S24
  • Nitrous oxide (50:50 O2 & NO)
  • IV opiates
  • Epidural/Spinal
  • Sedatives/hypnotics (1st stage or laboring down)

Question 6

Define the following terms. List the structures involved, where applicable:

Episiotomy - midline and mediolateral

Answer 6

• Midline:
  
  • Starts at the posterior fourchette and extends inferiorly through the central tendon of the perineal body, including the transverse perineal muscle.
  • Involves the skin, vaginal mucosa, and posterior fourchette and perineal muscles, but not the anal sphincter.
  • Equivalent to a second-degree laceration.
• Mediolateral (recommended over midline):
  
  • Begins at the midline in the posterior fourchette and extends laterally and inferiorly away from the rectum.
  • May be right or left mediolateral incision.
  • Structures involved: central tendinous point of perineum, fourchette, bulbocavernosus muscle, superficial & transverse perineal muscle, levator ani muscle–pubococcygeus.
  • Less likely to result in a third- or fourth-degree laceration

Question 7

Describe techniques for assisting parturients to deliver over an intact perineum

Answer 7

• Make certain the patient’s thighs and legs are not abducted laterally (no lithotomy)
• Use of warm compresses during the perineal phase may decrease the incidence of 3rd- and 4th-degree lacerations.
• Avoid vigorous or sustained perineal massage during the 2nd stage, as these may cause perineal edema and tearing.
• Deliver the fetus slowly between contractions controlling extension of the head so pressure on the perineum is not suddenly forceful.
• If blanching of the perineum is observed, encourage the woman to breathe instead of push, to support slower birth of the fetal head.

Question 8

Perineal Lacerations

1st degree

Answer 8

Involves the perineal skin only

Question 9

Perineal Lacerations

2nd degree

Answer 9

• Involves the skin, vaginal mucosa, and posterior fourchette,
• Extends into the perineal body fascia and musculature
  
  • Superficial and deep transverse perineal muscle and fibers of the pubococcygeus and bulbocavernosus muscles
• Does not involve the anal sphincter

Question 10

Perineal Lacerations

3rd degreee (A, B, C)

Answer 10

Involves the skin, vaginal mucosa, posterior fourchette, perineal muscles, and external anal sphincter

• 3a: < 50% of the external anal sphincter
• 3b: > 50% of the external anal sphincter
• 3c: Complete rupture of the external anal sphincter and the internal anal sphincter is torn

Question 11

Perineal Laceration

4th degree

Answer 11

• Involves the:
  
  • Skin, vaginal mucosa, posterior fourchette
  • Perineal muscles
  • Extending through the external and internal anal sphincter and anterior rectal mucosa

Question 12

Other lacerations:

Cervical

Answer 12

Laceration on any part of the cervix, usually on one or both of the lateral sides at approximately 3 o’clock and 9 o’clock, where the anterior and posterior aspects join

Question 13

Other lacerations:

Sulcus

Answer 13

Lacerations of the vaginal mucosa and underlying tissue along one or both sides of the posterior column of the vagina instead of the middle inferior part of the vagina

Question 14

Other lacerations:

Labial

Answer 14

Laceration that extends from the fourchette anteriorly in one or both of the labia majora bodies

Question 15

Other lacerations:

Periurethral

Answer 15

Longitudinal or transverse tear in the labia minora very near the urethra

Question 16

Other lacerations:

Clitoral

Answer 16

Periurethral tear that extends into or near the clitoral body

Question 17

Describe the purpose and indications for episiotomies

Answer 17

• Need to expedite birth secondary to fetal bradycardia or other FHR pattern that suggests a significant risk of newborn acidemia.
• Other suggested but controversial indications:
  
  • Include operative birth
  • Suspected shoulder dystocia
  • Short perineum (with a mediolateral episiotomy to avoid a spontaneous fourth-degree laceration).

Question 18

Identify indications, advantages, and disadvantages of midline episiotomy and mediolateral episiotomy

Answer 18

• Midline
  
  • Advantages:
    
    • Less nerve branches = less pain
    • Easier to repair
    • Better cosmetically
  • Disadvantages:
    
    • More likely to extend into 4th degree tear
• Mediolateral
  
  • Advantages:
    
    • Less likely to result in a 3rd- or 4th-degree laceration
  • Disadvantages:
    
    • Harder to repair
    • More painful healing (more nerves)

Question 19

Describe technique of cutting episiotomies

Answer 19

Technique:

• Place index & middle fingers of non-dominant hand into the perineal area to flatten perineum, palpate rectum, & protect head (creates space for scissors)
• Place scissors at appropriate depth (both midline & mediolateral will begin at posterior forchette)
  
  • Midline: cut above anal sphincter
  • Mediolateral: 40-60 degree angle or 1 cm of levator ani between incision & rectum
    
    • Too far laterally may incise bartholin gland
• ONE SINGLE INCISION–two if necessary
• DO NOT BLOT excessively or wipe - may cause additional trauma

Question 20

Describe the timing of cutting episiotomies (when clinically indicated)

Answer 20

Best time:

• Incision when the head is crowning and not retracting between contractions, such that birth is expected within a few contractions.
• Head well applied to the perineum → tamponade to decrease bleeding

Poor timing

• Too early may result in extra blood loss.
• Waiting until the perineum is paper thin and the tissue bulging may → rapid and perhaps uncontrolled birth of the fetal head, with resulting extension of the episiotomy.

Question 21

Describe the procedure for normal delivery

Answer 21

• Gather all equipment and supplies, including newborn resuscitation equipment
• Put on protective gear
  
  • Hair cover, booties, mask, protective eyewear
  • Sterile/waterproof gown
  • Sterile gloves (have extra pair handy)
• Arrange instruments on supply tray and maintain sterile field
  
  • 2 kelly clamps
  • Bandage scissors
  • Rings forceps
  • Bulb suction and gauze
  • Metzenbaum and mayo scissors
  • Hemostats
  • Repair supplies (tissue forceps, pickups, needle drivers)
  • Bowl for placenta
• Drape woman, tuck drape under bottom
• Position yourself with clear visual of/access to perineum
• Hands off approach until BPD visible at introitus (crowning)
• Then, use palmar surface of one hand to exert gentle downward pressure on bones of fetal skull to maintain flexion and control/slow birth of head
• Keep fingers in a straight plane with the hand
• Specific placement may vary depending on hand size, be sure you can see the perineum
• Some will choose a hands on approach, supporting perineum with warm compresses or by applying inward pressure on tissues with thumb and forefingers
• Do NOT routinely cut episiotomy
• Fetal head should be born between contractions, may need to direct woman NOT to push
• Use fingers to check for nuchal cord and manage, if present
• Can use sterile gauze to wipe baby’s face/nose/mouth, but no routine suctioning
• Use your hands to support baby on either side of it’s head with your pinkies to the perineum and fingers facing baby’s face/nose
• Once anterior shoulder is born
• Ask for 10 units pit IM, if active management at your institution
• Guide baby’s head/body up following curve of carus
• Body can be born with either
  
  • One step - immediate restitution/birth of body after head (mean time 24 sec) OR
  • Two step - wait for next contraction and spontaneous restitution and birth of shoulders (mean time 88 sec)
    
    • Some concern that longer head to body time (two step approach) causes more cord occlusion/acidemia and/or shoulder dystocia, neither claim supported by good evidence.
• Take care to pin arms/wrists/knees/ankles as body is born to minimize tearing
• Baby skin to skin on Mom
• Deliver placenta, massage fundus, inspect and repair perineum

Question 22

Describe the modified Ritgen maneuver. State indications for it.

Answer 22

• Used to control the birth of the head by controlling both flexion and extension of the head.
• Rarely used today to speed the birth by facilitating the process of extension through application of forward pressure on the fetal chin.
  
  • Vacuum or forceps are usually chosen for indicated operative vaginal birth

Procedure:

1. ​One hand remains on the occiput as the fetus is crowning to maintain flexion until after the biparietal diameters are visible at the introitus.
2. The other hand uses a gauze or sterile towel to protect against rectal contamination and palpates the fetal chin in the area between the maternal coccyx and rectum.
3. ​Forward and outward pressure is then exerted on the underneath side of the chin, and extension of the head is controlled between this hand and the hand exerting pressure on the occiput to control the pace of the birth of the infant’s head.

Question 23

Discuss controversy, including rationale, about when to clamp and cut the umbilical cord

Answer 23

• Delayed cord-clamping - wait at least 30 seconds (up to 5 minutes) after birth before clamping/cutting umbilical cord
  
  • Evidence-based, standard of care
  • Promotes the transition from intrauterine to extrauterine life and offers other health benefits.
  • Allows the blood circulating in the umbilical vessels and the placenta to return into the newborn’s circulation after birth (placental transfusion)
    
    • Increases blood volume in the newborn by approximately 30% and RBC volume by 50%.
      
      • Significant health benefits for all newborns
        
        • Better neurodevelopmental outcomes
        • Term - higher ferritin levels, reduces the risk of iron-deficiency anemia, and can increase stores of brain myelin
        • Preterm - less need for blood transfusions, decreased incidence of IVH and NEC, improved mean SBP, and reduced hospital mortality.

Question 24

Describe management of nuchal cord, including reducing, clamping and cutting, delivering through, and somersaulting the baby

Answer 24

​Cord reduction:

• If the cord is loose, slip it forward over the head before delivery of the shoulders (referred to as reducing the cord over the head).

​Birth through the cord:

• If the cord is too tight to reduce but still has some mobility, slip it back over the shoulders as the infant is born, allowing the infant to be born through the cord.

Somersault maneuver:

• If the cord is too tight to slip over the shoulders but loose enough to permit some movement, use one hand to keep the head close to the maternal thigh throughout the birth of the body and the other hand to “somersault” the body over the perineum, which will limit the traction placed on the cord.

​Clamp and cut:

• If the cord is too tight to accomplish the other preferred steps, double-clamp and cut the cord between the clamps at the neck before the infant’s body is born.