Conduct of Normal Labor & Delivery

Chap. 13 CONDUCT OF NORMAL LABOR AND DELIVERY


April 19, 1999

1st year resident. Sun-joo, Lee M.D.




I. Admittance Procedures


1. Identification of Labor


◆ Contractions of True Labor

  • at regular intervals.
  • gradually shorten.
  • intensity gradually increases.
  • discomfort is in back & abdomen.
  • cervix dilates.
  • discomfort is not stopped by sedation.


◆ Contractions of False Labor

  • at irregular intervals.
  • intervals remain long.
  • intensity remains unchanged.
  • discomfort is chiefly in lower abdomen.
  • cervix does not dilate.
  • discomfort is usually relieved by sedation.


(1) Electronic Admission Testing

  • fetal admission test - nonstress test(NST) or contraction stress test(CST).
  • NST : an assessment of fetal heart rate accelerations or lack of the same with fetal movement.
  • CST : before, during, and following a uterine contraction if the patient is in labor.


2. Admittance Vaginal Examination

1. Amnionic fluid : a sterile speculum is carefully inserted.

2. Cervix : softness, degree of effacement(length), extent of dilatation, location of the cervix.

3. Presenting part.

4. Station.

5. Pelvic architecture : diagonal conjugate, ischial spines, pelvic sidewalls, and sacrum.


(1) Cervical Effacement : is expressed in terms of the length of the cervical canal compared to that of an uneffaced cervix.

(2) Cervical Dilatation : by estimation the average diameter of the cervical opening.

(3) Position of the Cervix : posterior, mid position, or anterior.

(4) Station :

  • when the lower most portion of the presenting fetal part is at the level of the ischial spines → zero(0) station.
  • if the vertex is at 0 station or below, most often engagement of the head has occured.

(5) Detection of Ruptured Membranes

  • 1st : the possibility of prolapse of the umbilical cord & cord compression is greatly increased.
  • 2nd : labor is likely to occur soon.
  • 3rd : if delivery is delayed for 24hours or more after membrane rupture, there is increasing likelihood of serious intrauterine infection.

(6) Nitrazine Test : A pH above 6.5 is consistent with ruptured membranes.
  • cervical mucus ferning.
  • nile blue sulfate staining.
  • identification of high values of glucose, fructose, prolactin, -fetoprotein, diamine oxidase.
  • infection of various dyes, into the amnionic sac via abdominal amniocentesis.


3. Other Admittance Procedures

(1) Vital Signs and Review of Pregnancy Record

(2) Preparation of Vulva & Perineum

  • Scrubbing is directed from above, downward, and away from the introitus.

(3) Vaginal Examinations

  • It is important to avoid the anal region and not to withdraw the fingers from the vagina until the examination is completed.

(4) Enema

  • Fleet enema has proven satisfactory.

(5) Laboratory

  • hematocrit, or Hb concentration, a voided urine specimen.



II. Management of First Stage of Labor


  • Average duration : nulliparous women - 8 hours

                                    parous women - 5 hours


1. Monitoring Fetal Well-being During Labor
  • the frequency, intensity, and duration of uterine contractions, and the response of the FHR to the contractions.

(1) Fetal Heart Rate

  • fetal jeopardey, compromise, or distress is suspected if the FHR immediately after a contraction is repeatedly below 120 bpm.
  • 1st stage of labor

    - low risk : every 30 minutes iμ 15 minutes during 2nd stage.

    - high risk : every 15 minutes iμ 5 minutes.

(2) Uterine Contractions


2. Maternal Monitoring Management During Labor

(1) Maternal Position During Labor : the position she finds most comfortable(lateral recumbency).

(2) Subsequent Vaginal Examinations

(3) Analgesia : is initiated on the basis of the woman's discomfort.

(4) Maternal Vital Signs

  • temperature & pulse --> every 1 to 2 hours.
  • BP is obtained between contractions.
  • have been ruptured for many hours before the onset of labor, or if there is a borderline

    temperature elevation --> checked hourly.

(5) Amniotomy

  • more rapid labor, earlier detection of instances of meconium staining, to apply an
    electrode to the fetus and insert a pressure catheter into the uterine cavity.

(6) Oral Intake

  • Food should be withheld during active labor & delivery.

(7) Intravenous Fluids
  • to administer oxytocin.
  • to prevent dehydration & acidosis.

(8) Urinary Bladder Function

  • bladder distension can lead to obstructed labor and to subsequent bladder hypotonia & infection.

(9) Active Management of Labor

  • only in nulliparous women.
  • artificial amniotomy.
  • frequent cervical examination, oxytosin is given if cervical dilatation does not progress at least 1cm/hr.



III. Management of Second Stage of Labor


1. Identification

  • with full dilatation of the cervix, the onset of the 2nd stage of labor.
  • begins to bear down.
  • develops the urge to defecate.

2. Duration

  • median duration : 50 minutes in nulliparas.

                          20 minutes in multiparas.


(1) FHR

  • low-risk fetus : at least every 15 min.
  • high-risk fetus : at least every 5 min.

(2) Maternal Expulsive Efforts

  • legs : half-flexed.
  • take a deep breath as soon as the next uterine contraction begins, and with her breath held.

(3) Preparation for Delivery

  • dorsal lithotomy position in order to increase the diameter of the pelvic outlet.
  • preparation for delivery entails vulvar & perineal cleansing.


IV. Spontaneous Delivery


1. Delivery of the Head

  • crowning : the encirclement of the largest head diameter by the vulvar ring.
  • episiotomy :

    • individualization & do not universally cut an episiotomy.
    • increase the risk of a tear into the external anal sphincter and/or the rectum.
    • anterior tears are much more common in women in whom an episiotomy is not cut.


◆ Ritgen Maneuver

  • during a contraction enough to open the vaginal introitus to a diameter of 5cm or more, a towel-draped,

    gloved hand may be used to exert forward pressure on the chin of the fetus through the perineum just in front of the coccys.
  • the other hand exerts pressure superiorly against the occiput.



2. Delivery of Shoulders

  • the sides of the head are grasped with the two hands & gentle downward traction
    applied
    until the anteriou shoulder appears under the pubic arch.
  • Next, by an upward movement, the posterior shoulder is delivered.
  • Hooking the fingers in the axillae should be avoided.

(1) Clearing the Nasopharynx

  • to minimize the likelihood of aspiration of amnionic fluid debris and blood.

(2) Nuchal Cord

  • Following delivery of the anterior shoulder, the finger should be passed to the neck of the fetus.


3. Clamping the Cord
  • cut between two clamps placed 4 or 5cm from the fetal abdomen.

◆ Timing of Cord Clamping

  • to clamp the cord after 1st thoroughly clearing the infant's airway, all of which usually takes about 30 seconds.




V. Management of Third Stage of Labor


  • As long as the uteurs remains firm and there is no unusual bleeding, watchful waiting
    until the placenta is separated.
  • No massage is practiced.


1. Signs of Placental Separation
    1. The uterus becomes globular and firmer.

    2. sudden gush of blood.

    3. The uterus rises in the abdomen.

    4. The umbilical cord progrudes farther out of the vagina.



2. Delivery of the Placenta

  • Placental expression should never be forced before placentral separation.
  • uterus is lifted cephalad with the abdominal hand.

◆ Manual Removal of Placenta

  • If at any time there is brisk bleeding and the placenta cannot be delivered.

3. Active Management of the Third Stage
  • syntometrine (5 units of oxytocin with 0.5mg of ergometrine) management :
  • recuction in the length of the 3rd stage.
  • no reduction in blood loss.
  • more effective than oxytocin alone in the prevention of postpartum hemorrhage.

4. "4th Stage" of Labor
  • The hour immediately following delivery is critical.




VI. Lacerations of the Birth Canal


    1. 1st-degree lacerations : fourchette, perineal skin, vaginal mucous membranes.

    2. 2nd-degree lacerations : the fascia and muscles of the perineal body but not the rectal sphincter.

    3. 3rd-degree lacerations : the skin, mucous membrane, perineal body and anal sphincter.

    4. 4th-degree lacerations : through the rectal mucosa to expose the lumen of the rectum.




VII. Episiotomy and Repair



  • median or midline episiotomy.
  • mediolateral episiotomy.


1. Purposes

  • easier to repair.
  • mediolateral : the likelihood of a laceration into the rectum is reduced.
  • is associated with an increased incidence of anal sphincter and rectal tears.
  • should not be performed routinely.
  • Indication :
    • fetal indications (shoulder dystocia, breech delivery).
    • forceps or vacuum extractor operations.
    • occiput posterior positions.

2. Timing :
  • when the head is visible during a contraction to a diameter of 3 to 4cm.

3. Midline vs. Mediolateral Episiotomy

  • Except for the important issue of 3rd- & 4th-degree extensions, midline episiotomy is superior.
  • increased risk for 3rd- & 4th-degree lacerations :

  • nulliparity.
  • 2nd-stage arrest of labor.
  • persistent occiput posterior position.
  • mid- or low-forceps.
  • use of local anesthetics.
  • Asian race.

MIDLINE VS MEDIOLATERAL EPISIOTOMY














Episiotomy

Characteristic Midline Mediolateral

Surgical repair Easy More defficult
Faulty healing Rare More common
Postoperative pain Minimal Common
Anatomical results Excellent Occasionally faulty
Blood loss Less More
Dyspareunia Rare Occasional
Extensions Common Uncommon




    4. Timing of the Repair

    • to defer episiotomy repair until the placenta has been delivered.

    5. Technique
    • hemostasis & anatomical restoration without excessive suturing ar essential.

    ◆ 4th-Degree Laceratio

    • to approximate the torn edges of the rectal mucosa with muscularis sutures placed approximately 0.5cm apart.
    • Muscular layer then is covered with a layer of fascia.
    • The cut, ends of the anal sphincter are isolated, approximated, and sutured together.
    • Stool softeners should be prescribed for a week.
    • prophylactic antimicrobials.

    6. Pain After Episiotomy

    • a heat lamp.
    • an ice collar.
    • aerosol spray.
    • analgesics.
    • If pain is severe or persistent, it is essential to examine vulva, paravagina, or ischiorectum or perineum carefully