Normal (Vaginal) Delivery vs. Cesarean Section (C-Section)

PART 1: NORMAL (VAGINAL) DELIVERY

The Three Stages of Labor

• Latent phase: Mild, infrequent, irregular contractions. The cervix gradually effaces (thins) and softens. This preparatory phase may last many hours.
• Active phase: Begins once the cervix reaches ~3-4 cm dilation. Cervical dilation proceeds at an average rate of 1.2 cm/hr in nulliparous (first-time) and 1.5 cm/hr in multiparous women.

• First pregnancy (primigravida): ~12 hours
• Subsequent pregnancies (multigravida): ~7 hours

1. Engagement - the widest diameter of the head passes the pelvic inlet
2. Flexion - the head flexes onto the chest for a smaller diameter
3. Descent - the head descends through the pelvis
4. Internal rotation - the occiput rotates to face anteriorly (toward the pubic symphysis)
5. Extension - the head extends as it passes under the pubic arch; "crowning" occurs
6. External rotation (restitution) - the head turns to face the thigh, aligning the shoulders

• Prepare the perineum with soap, water, and povidone-iodine if time allows
• Gentle digital stretching of the inferior perineum to aid passage
• Episiotomy if needed (fetal distress, shoulder dystocia, instrumental delivery): inject 5-10 mL of 1% lidocaine; 2-3 cm incision either midline or mediolateral (45°). Mediolateral has lower risk of extension to the anal sphincter.
• Do not routinely suction the mouth and nose (can cause bradycardia and hypoxia)
• After head delivery: place the posterior hand under the axilla, grasp the ankles firmly ("don't drop the baby" - amniotic fluid, blood, and vernix make the infant very slippery)

• Duration: completed within 15 minutes in ~90% of births
• A placenta not delivered within 60 minutes is classified as a retained placenta
• Retraction of the uterus reduces the placental attachment area; a hematoma forms beneath the placenta and separates it from the uterine wall
• Myometrial contractions constrict the spiral arteries, preventing excessive bleeding

Assessment During Labor

• Normal fetal heart rate: 120-160 beats/min
• Bradycardia: <110 bpm; Tachycardia: >160 bpm
• Fetal distress signs: persistent bradycardia, tachycardia, or late decelerations (drops in heart rate during AND >30 seconds after a contraction)
• Fundal height in cm approximates gestational age in weeks (±2 weeks) after 20 weeks
• Gestational age estimate: last menstrual period + 9 months and 7 days (Naegele's rule)

PART 2: CESAREAN SECTION (C-SECTION)

Definition and History

Indications for C-Section

• Dystocia (failure of labor to progress / cephalopelvic disproportion) - accounts for ~30% of cases
• Repeat cesarean delivery (prior uterine scar)
• Breech presentation (especially footling breech)
• Fetal distress (non-reassuring fetal heart rate patterns)
• Placenta previa (placenta covering the cervical os)
• Very low birth weight (<1500 g) - to avoid birth trauma
• Multiple gestation with first twin in non-vertex position
• Macrosomia (estimated fetal weight >4500 g, or >4000 g in a diabetic mother)
• Maternal HIV infection (to reduce vertical transmission)
• Perimortem (cardiac arrest in a pregnant woman)
• Active genital herpes infection

Types of Uterine Incisions

Step-by-Step Surgical Technique (Low Transverse / Pfannenstiel Approach)

• Tilt table or place a wedge to the patient's left to improve venous return and fetal oxygenation
• Anesthesia: regional (epidural or spinal) preferred; general anesthesia when needed
• IV antibiotic prophylaxis: cefoxitin 1g IV (or clindamycin 600 mg IV for penicillin allergy) - given after cord clamping, reduces wound infection by 50%

1. Pfannenstiel skin incision: horizontal incision ~13-15 cm wide, two fingerbreadths above the pubic symphysis (No. 20 blade)
2. Subcutaneous dissection: carry down through fat to fascia; make a 2-cm horizontal fascial incision, extend laterally and superiorly with curved Mayo scissors
3. Fascial elevation: grasp the superior fascial edge with Kocher clamps; bluntly dissect fascia off the underlying rectus muscle along the linea alba
4. Peritoneal entry: bluntly separate the rectus muscles in the midline; tent the peritoneum with two hemostats and incise with the scalpel (keep above the bladder)
5. Bladder retraction: place DeLee bladder retractor
6. Bladder flap development: incise and dissect the peritoneum off the lower uterine segment ~12 cm wide; reapply the bladder retractor to protect the bladder
7. Uterine incision (scoring): incise the lower uterine segment over the fetal head, proceeding mm by mm to avoid fetal injury; announce "uterine incision" for the anesthesiologist and nursery team
8. Extend uterine incision: use fingers bluntly or bandage scissors (with two fingers inside protecting the fetus) to extend the incision ~10-11 cm in a curvilinear fashion
9. Rupture membranes: with Allis clamp if not already ruptured
10. Deliver the head: insert a cupped hand over the fetal head/occiput, keeping the wrist straight; gently lift upward. If the head is deeply engaged, an assistant pushes from below vaginally, or terbutaline 0.25 mg SC/IV is given to relax the uterus
11. Deliver body: suction the infant's mouth and nose; deliver anterior shoulder, then posterior shoulder, then the rest of the body (same as vaginal delivery)
12. Cord clamping: doubly clamp and cut the cord; send cord blood if required
13. Placenta delivery: manually extract with fingers; remove membranes with ring forceps
14. Uterine massage and inspection: Pennington clamps on bleeding edges; clean endometrium with moist lap sponges; if cervix closed, dilate with cervical dilators
15. Uterine closure: running locked stitch with 0 chromic suture (avoid including the endometrium); add a second imbrication layer if bleeding continues
16. Inspect: check uterus, tubes, ovaries; perform tubal ligation here if desired
17. Irrigation: irrigate the pouch of Douglas and abdominal cavity with warm saline; inspect appendix and gallbladder
18. Fascial closure: running stitch with 1-0 Vicryl, sutures no more than 1 cm apart
19. Skin closure: irrigate subcutaneous fat; skin closure with staples or suture

Complications of C-Section

• Hemorrhage requiring transfusion
• Wound infection (reduced by prophylactic antibiotics)
• Bladder or ureteral injury
• Bowel injury
• Postoperative ileus
• DVT and pulmonary embolism
• Endometritis/peritonitis
• Need for hysterectomy (rare)
• Future pregnancy risks: uterine rupture at scar site (~0.5% with trial of labor after cesarean / TOLAC); placenta previa or accreta

• Accidental scalpel lacerations (1-2% of cases, usually cosmetic only; rarely serious)
• Transient tachypnea of the newborn (due to retained lung fluid, more common with elective C-section vs. vaginal delivery)

Emergency / Perimortem C-Section

• Vertical skin incision from xiphoid to pubic symphysis
• Through skin, fat, fascia, and peritoneum
• Vertical uterine incision with two-finger protection of the fetus
• Deliver the fetus, suction airway, double-clamp and cut the cord
• Deliver the placenta and sweep the endometrial cavity

Key Comparisons: Normal Delivery vs. C-Section

• The Developing Human - Clinically Oriented Embryology, pp. 370-372
• Tintinalli's Emergency Medicine, Ch. 101
• Pfenninger and Fowler's Procedures for Primary Care, Ch. 162
• Creasy & Resnik's Maternal-Fetal Medicine: Principles and Practice, Ch. 40