Labor and Delivery

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 1

Labor and Delivery

CAPT Mike Hughey, MC, USNR


Labor• Regular, frequent, leading to

progressive cervical effacement and dilatation

• Braxton-Hicks contractions– May be painful and regular,

but usually are not– Do not lead to cervical change

• Labor diagnosis usually made in retrospect.

• Cause of labor is unknown


Latent Phase Labor• <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 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


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)


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

• Engagement (0 Station)• Descent• Flexion (fetal head flexed against the chest)• Internal rotation (fetal head rotates from transverse to anterior• Extension (head extends with crowning)• External rotation (head returns to its’ transverse orientation)• Expulsion (shoulders and torso of the baby are delivered)


Watch a Delivery


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


Initial Labor Management• Risk assessment• Contractions: frequency, duration, onset• Membranes: Ruptured, intact• Status of cervix: dilatation, effacement, station• Position of the fetus: vertex, transverse lie,

breech• Fetal status: fetal heart rate, EFM


Cervix

• Dilatation: How far has the cervix opened (in cm)

• Effacement: How thin is the cervix (in cm or %)


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


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


Management of Early Labor• Ambulation OK with

intact membranes• If in bed, lie on one

side or the other…not flat on her back

• Check vital signs every 4 hours

• NPO except ice chips or small sips of water


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• >160 BPM• Most are not suggestive of

fetal jeopardy• Associated with:

– Fever, Chorioamnionitis– Maternal hypothyroidism– Drugs (tocolytics, etc.)– Fetal hypoxia– Fetal anemia– Fetal arrythmia


Bradycardia• Sustained <120 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


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


Prolonged Decelerations

• Last > 60 seconds• Occur in isolation• Associated with:

– Maternal hypotension– Epidural– Paracervical block– Tetanic contractions– Umbilical cord prolapse


Pain Relief

• Narcotics• Continuous Lumbar

Epidural• Paracervical Block• 50/50 nitrous/oxygen• Psychoprophylaxis

(Lamaze breathing)• Hypnosis


Anesthesia During Delivery

• Local• Pudendal Block• Epidural• Caudal• Spinal• 50/50 nitrous/oxygen


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.


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


Labor and Delivery

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