Everything to know about a normal vaginal delivery for a new doctor

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Normal Vaginal Delivery - A Complete Guide for the New Doctor

1. Definition & Overview

Labor is the physiologic process by which the fetus, membranes, umbilical cord, and placenta are expelled from the uterus. A spontaneous vaginal delivery (SVD) occurs without forceps, vacuum, or cesarean section. Vaginal deliveries account for ~68% of births in the USA and ~80% worldwide.

Types:

Spontaneous - without instrumentation
Induced - labor triggered by medications/procedures
Operative/Assisted - with forceps or vacuum extractor

2. Criteria for Normal Labor ("4 Ps")

Factor	Normal Range
Power	Regular contractions, increasing frequency/intensity
Passenger	Fetus in vertex (cephalic) presentation, adequate flexion
Passage	Adequate pelvis; gynecoid pelvis is most favorable
Psyche	Patient prepared, cooperative, with support

Definition of labor onset: Regular uterine contractions causing progressive cervical dilation and effacement.

3. Stages of Labor

Stage 1 - Cervical Dilation (Onset of labor → Full dilation at 10 cm)

Divided into two phases:

Phase	Cervical Dilation	Duration (primigravida)	Duration (multigravida)
Latent phase	0 → 6 cm	Up to 20 hours	Up to 14 hours
Active phase	6 → 10 cm	~6 hours; minimum 0.5 cm/hr	Faster

Contractions in active phase: every 2-3 min, lasting 45-60 seconds, moderate-to-strong intensity
Total Stage 1 duration averages 12-19 hours in nulliparas

Stage 2 - Expulsion (Full dilation → Delivery of baby)

Begins when cervix is fully dilated (10 cm, 100% effaced)
Patient actively pushes with contractions
Duration: up to 3 hours with epidural, 2 hours without (nullipara); up to 2 hours / 1 hour (multipara)
Monitor FHR every 5 minutes and after each contraction

Stage 3 - Placental Delivery (Baby's birth → Placenta delivered)

Usually occurs within 5-30 minutes of delivery
Normal blood loss: 200-300 mL (>500 mL = excessive)
Schultze mechanism (80%): Central separation first; fetal surface delivers first; less blood loss
Duncan mechanism (20%): Lower edge separates first; placenta slides sideways; more bleeding risk

Stage 4 - Recovery (1st hour postpartum)

Monitor for postpartum hemorrhage, uterine atony, vital signs

4. The Cardinal Movements (Mechanism of Labor)

These are the 7 sequential positional changes of the fetal head during descent. They occur in a continuous, overlapping fashion but are taught as discrete steps:

#	Movement	What Happens
1. Engagement	Biparietal diameter (BPD) passes below the pelvic inlet; occiput at or below ischial spines = engaged
2. Descent	Progressive downward movement of presenting part through the pelvis
3. Flexion	Head flexes so chin meets chest; smaller suboccipitobregmatic diameter (9.5 cm) presents
4. Internal Rotation	Occiput rotates from transverse → anterior (OA position) to align with AP diameter of outlet
5. Extension	Head extends under the pubic symphysis; face and chin emerge
6. Restitution & External Rotation	Head rotates back to align with fetal shoulders (which are now in AP diameter)
7. Expulsion	Anterior shoulder delivers under symphysis → posterior shoulder over perineum → rest of body follows

5. Clinical Assessment on Admission

History to elicit:

Gestational age (confirmed EDD)
Onset, frequency, duration, intensity of contractions
Status of membranes (SROM? color of fluid - clear/green/bloody?)
Fetal movement
Vaginal bleeding (quantity, character)
Prior obstetric history, antenatal complications
Blood type, GBS status, HIV, hepatitis B

Physical Examination:

Vital signs, fundal height, fetal lie and presentation (Leopold maneuvers)
Fetal heart rate (normal: 110-160 bpm)
Vaginal exam: cervical dilation, effacement, station, position, membrane status

Station is measured in cm relative to the ischial spines (-5 to +5). At +5, the presenting part is on the perineum and may distend the vulva.

Leopold Maneuvers (4 steps):

Fundal grip - what is in the fundus?
Lateral grip - where is the fetal back?
Pawlik grip - presenting part above pelvis?
Deep pelvic grip - attitude/flexion/engagement?

6. Management of the First Stage

Encourage the patient to ambulate or find a comfortable position (walking, lateral decubitus, sitting)
FHR monitoring: every 15 minutes during and after contractions (or continuously in most units)
Assess contractions and cervical progress periodically
Avoid bladder distension - encourage voiding; catheterize if unable
NPO except ice chips
IV access; CBC, blood type & screen

Partogram/partograph: Graph of cervical dilation vs. time. Action line at +4 hours from alert line. Use it to detect labor dystocia early.

Abnormal patterns to recognize:

Prolonged latent phase (>20 hr nullipara, >14 hr multipara)
Active phase arrest (no change in 4+ hours with adequate contractions)
Secondary arrest of dilation

7. Pain Management

Method	Details
Systemic narcotics	Meperidine 25 mg IM/IV or Nalbuphine 10 mg IV. Avoid near delivery (neonatal respiratory depression). Antidote: Naloxone 0.01 mg/kg IV to neonate
Pudendal block	5 mL of 1% lidocaine into pudendal canal; covers vaginal introitus and perineum; used in 2nd stage; takes ~10 min to work
Epidural analgesia	Most popular; bupivacaine ± fentanyl; covers T10-L1 (1st stage) and S2-S4 (2nd stage). Contraindicated in: patient refusal, hemorrhage, septicemia, infection at site, coagulopathy. Side effects: hypotension, dural puncture headache
Psychological methods	Lamaze, breathing techniques, acupuncture, biofeedback

8. Second Stage Management - Delivery of the Baby

Positioning options:

Dorsal lithotomy (most common)
Lateral (Sims) position
Partial sitting/squatting
Hands and knees

Steps at crowning:

Support the perineum with a warm compress
Once introitus distended ≥5 cm, apply gentle pressure to fetal occiput with one hand (Ritgen maneuver)
Apply upward pressure through the perineum under the fetal chin with the other hand
Guide the head - tell the patient when to push and when to pause to minimize perineal tears
Check for nuchal cord (cord around the neck) - slip over the head if loose; if tight, double-clamp and cut
After head delivery, suction mouth then nose with bulb syringe
Check fetal position - shoulders should now be in AP orientation
Gentle downward pressure on the head to deliver the anterior shoulder under the symphysis
Lift the head to deliver the posterior shoulder over the perineum
Rest of the body follows

Shoulder dystocia - if anterior shoulder does not deliver with standard maneuvers, call for help and initiate McRoberts maneuver (hyperflexion of maternal thighs), suprapubic pressure, and further maneuvers.

9. Episiotomy

A surgical incision in the perineum to enlarge the introitus:

Type	Description	Notes
Median (midline)	Straight down toward anus	Most common in USA; easier repair
Mediolateral	Diagonal to one side	Reduces rectal extension but harder to repair, more pain

When to perform: Head crowning 3-4 cm; incision ~5-6 cm into vagina.

Current evidence: Routine episiotomy is NOT recommended. Restricted to specific indications (shoulder dystocia, fetal distress requiring rapid delivery, operative delivery). Routine episiotomy does NOT prevent pelvic floor damage, incontinence, or perineal trauma - Textbook of Family Medicine, 9e.

Perineal laceration degrees:

Degree	Tissue Involved
1st	Skin/mucosa only; often no repair needed
2nd	Mucosa + deeper vaginal/perineal tissues
3rd	Involves anal sphincter
4th	Through rectal mucosa + transects anal sphincter

10. Third Stage - Delivery of the Placenta

Active Management of the Third Stage (AMTSL) - reduces PPH risk significantly:

Oxytocin 10 units IM immediately after baby delivers (or 20 units/1000 mL saline at 125 mL/hr IV infusion). Do NOT give as IV bolus (risk of cardiac arrhythmia)
Controlled cord traction (Brandt-Andrews maneuver): Hold cord taut while placing a hand on the fundus to detect uterine contractions; pull cord gently downward as uterus contracts
Uterine massage after placenta delivers

Signs of placental separation:

Gush of blood
Cord lengthens
Uterus rises and becomes globular
Fundus firm on palpation

Delivery: Patient bears down; if unable, apply firm caudal pressure on the uterus abdominally only if uterus is firm (never on a flaccid uterus - risk of uterine inversion).

Placenta inspection (mandatory):

Check completeness: all cotyledons present, regular surface
Umbilical cord: 3 vessels (2 arteries + 1 vein); single umbilical artery associated with renal anomalies
Intact membranes

11. Cord Clamping

Delayed cord clamping (DCC): Clamp umbilical cord no earlier than 30-60 seconds after birth (per AMBOSS/ACOG)
Benefits: increased iron stores, improved hemoglobin in newborn
Exception: if immediate resuscitation needed

12. Immediate Newborn Care

Action	Timing
Dry and stimulate	Immediately
Assess APGAR score	At 1 min and 5 min
Maintain warmth (prevent hypothermia)	Ongoing
Early skin-to-skin contact	Immediately if stable
Initiate breastfeeding	Within first hour
Vitamin K 1 mg IM	Within first hour
Erythromycin eye ointment	Per protocol
Neonatal resuscitation if needed	NRP algorithm

APGAR Score:

Score	0	1	2
Appearance (color)	Blue all over	Pink body, blue extremities	Pink all over
Pulse	Absent	<100	≥100
Grimace (reflex)	No response	Grimace	Cry/cough/sneeze
Activity (tone)	Limp	Some flexion	Active motion
Respiration	Absent	Weak/irregular	Strong cry

Score 7-10: Normal
Score 4-6: Moderate depression; stimulation, supplemental O2
Score 0-3: Severe; immediate resuscitation

13. Postpartum Care (4th Stage)

Monitor every 15 minutes for 1 hour then every 30 minutes:
- Uterine firmness (fundal check)
- Vaginal bleeding
- Vital signs
- Bladder distension
Repair lacerations/episiotomy under adequate analgesia
Encourage breastfeeding
Document estimated blood loss

Postpartum Hemorrhage (PPH): Blood loss >500 mL after vaginal delivery. Most common cause = uterine atony. Use "4 Ts" mnemonic: Tone (atony), Trauma, Tissue (retained), Thrombin (coagulopathy).

14. Key Red Flags During Labor

Finding	Concern
FHR <110 or >160 bpm	Fetal distress
Late decelerations, prolonged deceleration	Uteroplacental insufficiency
Cord prolapse	Obstetric emergency - immediate C-section
Meconium-stained fluid (thick green)	Fetal distress; NICU team on standby
Failure to progress despite adequate contractions	Consider augmentation or C-section
Maternal BP >160/110	Pre-eclampsia/eclampsia
>500 mL blood loss	PPH

15. Quick Reference Summary

ADMIT → History + Exam + Labs + FHR monitoring
        ↓
STAGE 1: Support labor, pain control, progress checks every 2-4 hrs
        ↓
STAGE 2 (10 cm): Coach pushing, guide head, check nuchal cord, 
                 deliver shoulders, suction airway
        ↓
CORD: Delayed clamp ≥30-60 sec → cut
        ↓
NEWBORN: Dry, warm, APGAR, Vit K, skin-to-skin
        ↓
STAGE 3: Oxytocin IM → controlled cord traction → placenta out
         Inspect placenta (cotyledons + 3 vessels)
        ↓
STAGE 4: Repair lacerations, monitor for PPH, vitals q15min x 1hr

Sources: Textbook of Family Medicine, 9e (Intrapartum Procedures chapter); Park's Textbook of Preventive and Social Medicine; Merck Manual - Management of Spontaneous Vaginal Delivery; Medscape - Normal Labor and Delivery; AMBOSS - Normal Labor and Delivery

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