Obstetrics Marrow Pg 535-544 (Labor & Puerperium)

Occipito-Posterior Malposition (OP)

• Longitudinal lie, cephalic presentation, vertex presenting part.
• 6 (ROP) > 7 (DOP) > 8 (LOP) are the most common positions.
• Android pelvis and deflexed head are the main causes.
• Occurs in 10% of pregnancies at term and onset of labor.
• Decreases to 2% later in labor as the baby rotates to occipito-anterior.
• More common in multiparous women.
• Most frequent in nulliparous women.

Perineal Tear Classification

• Divided into 4 degrees based on structures involved.
• Degree 1: Vaginal mucosa
• Degree 2: Vaginal mucosa and muscles
• Degree 3A: < 50% external anal sphincter
• Degree 3B: ≥ 50% external anal sphincter
• Degree 3C: Internal and external anal sphincters
• Degree 4: Internal and external anal sphincters, and rectal mucosa.

### Repair of Perineal Tears

• 1st and 2nd degree tears repaired in the labor room under local anesthesia.
• 3rd and 4th degree tears repaired in the operating theater under general or spinal anesthesia.
• Repair sequence: vaginal mucosa (continuous sutures), muscles (interrupted sutures), vaginal skin (mattress suture), rectal mucosa, internal anal sphincter, external anal sphincter (end-to-end anastomosis).
• Immediate repair within 24 hours of delivery, delayed repair after minimum 3 weeks for tears older than 24 hours.

### WHO Recommendations to Prevent Perineal Tears

• Perineal massage
• Warm compression of perineum
• Controlled delivery of the fetal head
• Guarding the perineum
• Ritgen maneuver

### Not Recommended by WHO

• Fundal massage
• Routine episiotomy

### Episiotomy

• Surgical incision of the perineum to facilitate delivery of the fetal head
• Indications include shoulder dystocia, instrumental delivery, after-coming head of breech.
• Other factors: face to pubis delivery, macrosomia, rigid perineum; all increase the chance of tearing.

### Types of Episiotomy

• Median episiotomy cuts fewer muscle fibers, with easier bleeding management and quicker repair and healing. Less chance of gaping and dyspareunia. It involves the anal sphincter.
• Mediolateral episiotomy cuts more muscle fibers with more difficult bleeding management, longer repair and healing times. It has a greater chance of gaping and dyspareunia. It does not involve the anal sphincter.

Structures Cut in Episiotomy

• Vaginal mucosa
• Skin subcutaneous tissue
• Branches of the pudendal artery and nerve
• Muscles

Muscled Cut in Episiotomy

• Pubococcygeus
• Deep transverse perinei
• Superficial transverse perinei
• Bulbospongiosus

Muscles Not Cut in Episiotomy

• Ischiocavernosus
• Ischiococcygeus
• Obturator
• Anal sphincter

Timing of Episiotomy

• Performed after crowning, during perineal climbing in breech births, before or after forceps application, or before traction.

Vulval Hematoma

• Laceration of underlying blood vessels.
• Most commonly caused by instrumental delivery.
• Other causes include precipitate labor and rarely, spontaneous labor.
• Presents as localized excruciating pain after delivery, inability to urinate, and hypovolemia.
• Involves the internal pudendal artery for vulval hematomas and the vaginal artery for vaginal hematomas.
• On examination, a tense, tender, fluctuant swelling with bluish discoloration can be seen.
• Conservative managed with ice packs, analgesics and vital signs monitoring.
• Surgical management indicated for hematomas greater than 5cm or increasing in size.

Placenta Accreta Spectrum

• Normal placenta, placenta accreta, placenta increta, placenta percreta.
• Placenta accreta is the most common and occurs when the chorionic villi are superficially attached to the myometrium.
• Placenta increta happens when the chorionic villi invade the myometrium.
• Placenta percreta occurs when the chorionic villi attach to the serosa.
• Risk factors: placenta previa, previous c-section, dilatation & curettage, and myomectomy.
• Etiology includes absent Nitabuch's layer and defective decidua basalis.
• Investigated with ultrasound and Doppler: heterogeneous placenta, moth-eaten placenta, placental lakes, absence of the hypoechoic area below the placenta (decidua basalis), white line of bladder serosa interface interruption.
• Management involves hysterectomy.

Uterine Inversion

• Prolapse of the fundus of the uterus into the uterine cavity.
• Differentiated from uterine prolapse by a visible os.
• Managed with resuscitation, stopping uterotonics (Oxytocin).
• Manual replacement using Johnson's method, where the first prolapsed part is the last to be reposited, avoiding separation of the placenta to decrease the risk of hemorrhage.
• If manual replacement fails, repeat under general anesthesia or with uterine relaxant.
• Huntington's or Haltane's methods in cases of further failure.
• Haultain's method for constricted rings.
• Outdated methods: hydrostatic Osullivan method, vaginal surgeries like Spinelli and Cascardics.

Amniotic Fluid Embolism (AFE)

• Entry of amniotic fluid into the maternal circulation
• Also called anaphylactoid syndrome of pregnancy
• A catastrophic obstetric emergency
• Incidence of 1 in 100,000 deliveries
• Pathophysiology: Erratic uterine contractions, breach in the maternal-fetal interface, opening of venous sinuses allowing amniotic fluid (including fetal skin cells, debris, and antigens) to enter the maternal and then pulmonary circulation.

Post-Replacement Management

• Stop uterine relaxant
• Remove placenta
• Start oxytocin
• Start antibiotics

Amniotic Fluid Embolism (AFE) Clinical Features

• Phase 1 (during labor/immediately after delivery): Respiratory difficulty, shock, minimal bleeding.

### Post-partum Collapse Diagnosis

• PPH - Postpartum Hemorrhage, DIC -Disseminated Intravascular Coagulation

Occipito-posterior vs.Occipito-anterior

### Outcomes in OP Position

### Labor and Puerperium

• Classified based on the time of occurrence into acute and chronic types.
• Acute postpartum hemorrhage occurs within 24 hours post-delivery.