NORMAL LABOR AND DELIVERY #1

I. RELATIONSHIP OF FETUS AND BIRTH CANAL

A. Fetal Lie

  • Definition: The relationship of the fetal long axis to that of the mother.

  • Types:

    • Longitudinal: 99% term fetus

    • Oblique: 45-degree angle, unstable, can turn into longitudinal or transverse.

    • Transverse: Predisposing factors include:

      • Multiparity: Uterus becomes lax and stretchable.

      • Placenta previa: Placenta is low-lying; adjusts fetal position.

      • Hydramnios: Increased amniotic fluid allows for more fetal movement.

      • Uterine anomalies

B. Fetal Presentation

  • Definition: Portion of the fetal body that is foremost within or in close proximity to the birth canal.

  • Types:

    • Cephalic:

      • Subtypes:

        • Vertex: Full flexion; occipital fontanelle is the presenting part.

        • Sinciput: Neck partially flexed; anterior fontanelle presents.

        • Brow: Neck partially extended.

        • Face: Neck sharply extended; face is presenting.

    • Breech: Buttocks towards the pelvis. Can result from circumstances preventing the normal version.

      • Classifications:

        • Frank Breech: Thighs flexed in abdomen.

        • Complete Breech: Thighs flexed over the abdomen; legs flexed at the thighs.

        • Incomplete Breech/Footling: One or both thighs extended.

  • Delivery Considerations:

    • Primigravida with breech presentation is advised to proceed with Cesarean delivery.

    • Multigravida may consider Partial Breech Extraction (PBE) due to previous deliveries.

C. Fetal Attitude

  • Definition: Relationship of fetal parts to one another, indicating the characteristic posture of the fetus in utero.

  • Normal Habitus:

    • Uterus: Ovoid.

    • Back: Convex.

    • Head: Sharply flexed.

    • Chin: Almost in contact with the chest.

    • Thighs: Flexed over the abdomen.

    • Legs: Bent.

    • Arms: Crossed over thorax.

D. Fetal Position

  • Definition: Relationship of the fetal presenting part to the right or left side of the birth canal.

  • Statistics:

    • Approximately ⅔ of all vertex presentations are Left Occiput (LO) position, and ⅓ are Right Occiput (RO).

  • Abbreviations Used:

    • Vertex: Occiput (O)

    • Face: Mentum/Chin (M)

    • Breech: Sacrum (S)

    • Shoulder: Acromion (Ac)

II. DIAGNOSIS OF LIE, PRESENTATION, AND POSITION

A. Leopold’s Maneuver

  • Method: Systematic four abdominal maneuvers to diagnose fetal lie, position, and presentation.

  • Procedure:

    • Mother lies supine; abdomen bared.

    • Performed during later months of pregnancy or between contractions.

  • Four Grips:

    • L1 Fundal Grip: Identifies fetal lie and pole (cephalic or podalic) depending on mass felt.

    • L2 Umbilical Grip: Determines fetal orientation and position; feel back and extremities.

    • L3 Pawlik’s Grip: Assess fetal presentation; check for engaged presenting part.

    • L4 Pelvic Grip: Assesses degree of descent; checks location of cephalic prominence.

B. Internal Examination

  • Purpose: Identify presenting part and position of fetal fontanelles.

  • Workflow:

    • Direct finger posteriorly if vertex; assess positions based on fontanelle palpation.

C. Sonography

  • Use in early recognition of breech/shoulder presentations, especially in obese women with rigid abdominal walls.

III. CARDINAL MOVEMENTS OF LABOR

A. Engagement

  • Mechanism by which the biparietal diameter (9.5 cm) passes through the pelvic inlet.

  • Presence of a "floating" head above the inlet at labor's onset, particularly in multiparous patients.

B. Descent

  • Defined as the downward passage of the presenting part through the pelvis; occurs intermittently with contractions.

  • Forces involved:

    1. Pressure of amniotic fluid

    2. Direct uterine pressure during contractions

    3. Maternal abdominal muscle contractions

    4. Extension and straightening of the fetal body

C. Flexion

  • Results from fetal head encountering resistance from the bony pelvis/smooth tissue; brings chin into tight contact with the thorax.

  • Diameter Change: The suboccipitobregmatic diameter (9.5 cm) becomes a primary passageway instead of occipitofrontal (11 cm).

D. Internal Rotation

  • Rotary movement of the fetal head transitioning from transverse to anteroposterior position.

  • Requires favorable uterine contractions and maternal pelvic tone; essential for labor completion.

E. Extension

  • Occurs when the head contacts the pelvic floor; upward resistance from the pelvic floor and downward uterine contractions cause occiput extension.

F. External Rotation

  • Also known as restitution; reverts fetal head to its anatomic alignment with the fetal trunk.

G. Expulsion

  • Final delivery phase where the rest of the fetus is delivered after shoulder rotation; may encounter complications like shoulder dystocia if anterior shoulder becomes stuck.

IV. CHANGES IN THE SHAPE OF THE FETAL HEAD

A. Caput Succedaneum

  • Swelling of the fetal scalp at the cervical os due to prolonged labor prior to cervical dilatation.

  • Typically resolves within a few days post-delivery.

B. Cephalhematoma

  • Distinct from caput succedaneum; blood accumulation between skull bones and periosteum occurring after delivery.

C. Molding

  • Occurs as labor progresses and allows better adaptation of the fetal head to the birth canal; involves suturing compression and temporary skull asymmetry.

V. LABOR

Definition

  • Regular uterine contractions leading to progressive cervical changes (dilatation and effacement).

True vs False Labor

Characteristic

True Labor

False Labor

Intervals

Regular intervals

Irregular intervals

Interval length

Gradually shorter

Gradually longer

Intensity

Gradually increases

Unchanged or decreasing

Discomfort

In the back/abdomen

Lower abdomen chiefly

Sedation effect

Not relieved

Relieved

Cervical change

Cervix dilates

Cervix does not dilate

Phases of Parturition

  • 1st Phase (Quiescence, Activation, Stimulation, Involution):

    • Stimulation stage: contains 3 divisions:

      • Preparatory division: Cervical changes; sedation can halt this labor.

      • Dilatational division: Rapid dilation occurs here, unaffected by sedation.

      • Pelvic division: Cardinal movements take place during this phase.

  • 2 Phases of Cervical Dilatation:

    • Latent phase: Slow dilation (< 4 cm), irregular contractions.

    • Active phase: Rapid dilation (> 6 cm) with maximum slope.

References

  • Fariñas, M., (2026). NORMAL LABOR AND DELIVERY ppt.

  • Spong, C. Y., & Dashe, J. S. (2022). Williams obstetrics (25th ed.). McGraw-Hill Education.

  • Luna, JTP. et.al (2021). OB-GYN Platinum. 1st edition. Top Practice Medical Publishing Corporation

  • Villafuerte, M., & Villafuerte, A. (2019). OB-GYNE Gold. 3rd edition.