Labor and Delivery

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

Labor and Delivery

CAPT Mike Hughey, MC, USNR

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 2

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 3

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 4

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 5

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)

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 6

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 7

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)

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 8

Watch a Delivery

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 9

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 10

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 11

Cervix

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

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 12

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 13

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 14

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 15

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 16

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 17

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 18

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 19

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 20

Late Decelerations• Repetive, non-

remediable slowings of the fetal heartbeat toward the end of the contraction cycle

• Reflect utero-placental insufficiency

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 21

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 22

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 23

Severe Variable Decelerations

• Below 60 BPM for at least 60 seconds

• If persistent, can be threatening to fetal well-being, with progressive acidosis

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 24

Prolonged Decelerations

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

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 25

Pain Relief

• Narcotics• Continuous Lumbar

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

(Lamaze breathing)• Hypnosis

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 26

Anesthesia During Delivery

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 27

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.

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 28

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

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 29

Inspect the Placenta

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

blood clot

Operational Obstetrics & Gynecology · Bureau of Medicine and Surgery · 2000 Slide 30