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What is the primary factor affecting placental separation during the third stage of labour?
Active management of the third stage of labour is preferred due to a higher risk of postpartum hemorrhage.
False
What is the surest sign that the placenta is in the vagina?
Apparent and permanent lengthening of the cord
The _____ method is the primary technique used for placental separation during the third stage of labour.
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Match the following components of active management with their functions:
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What is the primary site for a pudendal nerve block?
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A paracervical block can be applied at the 3 o'clock position.
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What are the two main uses of prostaglandins during labor?
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The pudendal nerve block is particularly effective in relieving pain during the __________ stage of labor.
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Match the following anesthesia techniques with their primary purposes:
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What is the first stage of labor described in the process of a normal delivery?
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The fetal head flexes after it descends onto the levator ani muscle during labor.
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What term describes the position of the fetal head noted in the labor process?
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During delivery, the fetal shoulders rotate by ___ of a circle.
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Match the following stages of labor with their descriptions:
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What is the primary characteristic of anterior asynclitism?
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Epidural analgesia blocks both sensory and motor functions.
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What is the drug of choice (DOC) for epidural analgesia?
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During the second stage of labor, pain radiates to __________.
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Match the following stages of labor and their pain characteristics:
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What is the maximum score for the Bishop score?
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A Bishop score of 6 indicates that the cervix is not favorable for induction of labor.
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Name one method used for cervical ripening before induction of labor.
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The _____ score is modified by replacing the Position of Cx with the Length of Cx.
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Match the following parameters of the Bishop score to their respective ranges:
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What is the primary purpose of transcervical Foley's catheter in induction of labor?
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The use of prostaglandins is contraindicated in patients with a scarred uterus.
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What is the maximum number of doses for Misoprostol during induction of labor?
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The method used to separate membranes during labor induction involves the inflation of a Foley's catheter bulb with __________ mL of saline.
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Match the following induction methods with their descriptions:
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What is the maximum number of doses for Dinoprostone (Cerviprime gel) after 6 hours?
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Oxytocin can be directly used if the cervix is not ripe.
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Name one contraindication for vaginal delivery (C/I) during induction of labor (IOL).
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The maximum dose of oxytocin is _____ drops per minute.
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Match the methods of induction of labor (IOL) with their correct usage:
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What instrument is typically used for the artificial rupture of membranes (ARM)?
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The augmentation of labor can be indicated in cases of maternal HIV.
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List two absolute contraindications for the artificial rupture of membranes.
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The first cardinal movement of labor is ______.
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Match the following procedures with their effects:
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At what stage does engagement typically occur for multigravida women?
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A deflexed head is the most common cause of unengagement in primigravida at term.
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What is the engagement AP diameter when the head is in a fully flexed position?
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Engagement is determined when the largest transverse diameter of the fetal head crosses the _____ inlet.
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Match the degree of flexion with the corresponding presenting part and engaging AP diameter:
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What is the correct storage temperature for Oxytocin?
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Methylergometrine is recommended as the first-line treatment for managing postpartum hemorrhage immediately after delivery.
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What is the primary difference in contraction types between Oxytocin and Methylergometrine?
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Carboprost is administered at a dose of ______ mcg slow IV over 1 minute.
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Match the uterotonic agents with their key attributes:
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Study Notes
Third Stage of Labour
- Starts after delivery of baby and ends with delivery of the placenta.
- Uterine contractions are the main factor affecting placental separation.
- Placental separation occurs through the zona spongiosa.
- Schultz method is the most common method of placental separation.
- The surest sign of placental separation is feeling the placenta in the vagina, a lengthening of the umbilical cord, and a firm contracting uterus.
Passive Management of Third Stage of Labour
- Not preferred due to an increased risk of postpartum haemorrhage (PPH) and maternal mortality.
- Waiting for the placenta to be expelled spontaneously can take up to 15 minutes.
Active Management of Third Stage of Labour (AMTSL)
- Preferred because it shortens the third stage of labor, reduces blood loss, prevents PPH, and minimizes maternal mortality.
- The main drawback is an increased chance of retained placenta, which is treated with uterotonics.
Steps of Management
- Inject a uterotonic into the mother 1 minute after delivery or at the time of delivery of the anterior shoulder.
- Delayed cord clamping is recommended.
- Controlled cord traction is used to deliver the placenta.
- Intermittent assessment of uterine tone is crucial during the third stage.
Pudendal Nerve Block
- The pudendal nerve is blocked at the ischial spine by piercing the sacrospinous ligament.
- Pain relief is achieved in the second stage of labor.
- It's used during instrumental deliveries and repairs of perineal or vaginal tears.
- It does not block pain associated with cervical tear repair.
Paracervical Block
- Performed at 2, 4, 8, or 10 o'clock positions, avoiding 3 or 9 o'clock due to the descending cervical artery.
- The block lasts for 1 to 2 hours.
- Used during cervical repair, suction and evacuation procedures.
Prostaglandins
- Present on the myometrium and cervix, acting through G-protein cell membrane receptors.
- Released locally through paracrine action.
- Synthesized in the decidua and myometrium, with PGF2α primarily responsible for uterine action.
- In the amnion, PGE2α acts on the cervix.
- Used for inducing labor by sweeping membranes, augmenting labor, and managing PPH.
Asynclitic Engagement
- The head is deflected either anteriorly or posteriorly, described in terms of the parietal bone of the fetal head.
Anterior Asynclitism
- The sagittal suture is deflected towards the sacrum.
- The anterior parietal bone presents, with a better prognosis.
Posterior Asynclitism
- The sagittal suture is deflected towards the pubic symphysis.
- The posterior parietal bone presents.
Pain During Labour
- Uterine contractions radiate to T10-L1 during the 1st stage.
- Cervical dilation radiates to S2-S4 during both the 1st and 2nd stages.
- Perineal stretching during the 2nd stage is primarily mediated by the pudendal nerve (S2-S4).
Epidural Analgesia
- Provides sensory and sympathetic block at the T10 segment, but no motor block.
- Typically uses 0.625% Bupivacaine or Ropivacaine.
Effects of Epidural Analgesia
- Shortens the 1st stage of labor.
- Prolongs the 2nd stage of labor by 1 hour.
Monitoring of Epidural Analgesia
-
Closely monitor the patient's blood pressure and fetal heart rate.
-
During a C-section, anesthesia is provided at the T4 segment to block pain from the peritoneum.
-
Epidural anesthesia does not increase the rate of C-section.
Process of Labor
- This document describes the process of labor focusing on the stages of a normal delivery (longitudinal lie, cephalic presentation).
Stages and Descriptions
- Engagement of head: The head settles into the pelvis.
- Descent of fetal head onto levator ani muscle: The fetal head moves further down the birth canal.
- Flexion of head: The fetal head flexes.
- Internal Rotation: The fetal occiput rotates 45° at the level of the ischial spine.
- Crowning: The head becomes visible at the vaginal opening.
- Extension for delivery of head: The head is extended.
- Untwisting of neck (Restitution): The head rotates further.
- External Rotation: The shoulder rotates 1/8th of a circle.
- Expulsion of the baby: The baby is delivered.
Important information
- The most common presenting part is the vertex.
- The most common position of the head is LOT (Left Occipito-Transverse).
Mechanical Methods
- Ripen the cervix and induce labor, preferred in cases of scarred uteri.
1. Transcervical Foley's Catheter
- Inserted into the endocervical canal and inflated with 30 mL of normal saline (NS).
- The bulb sits against the internal os, stretching the cervix and releasing prostaglandins.
2. Extra Amniotic Saline Infusion (EASI)
- A Foley's catheter is inserted into the endocervical canal and inflated with 30-40 mL/hr of NS.
- The saline solution accumulates in the amniotic space leading to separation of membranes and release of prostaglandins.
3. Hydroscopic Dilators
- Laminaria tent, a seaweed dilator, is used for cervical ripening.
Prostaglandins
- Contraindicated in a scarred uterus.
- Can cause tachysystole (excessive contractions) and different agents have different risk profiles: Cervidil > Cerviprime > Misoprostol.
Misoprostol (PGE2)
- Administered orally or vaginally at a dose of 25 mcg, repeated every 3-6 hours with a maximum of 6 doses.
- A 4-hour gap with no induction of labor (IOL) means oxytocin can be used.
- Possible side effects: fetal heart rate abnormalities and meconium staining in the newborn.
Induction of Labor
- The Bishop score assesses the readiness of the cervix and uterus before induction of labor (IOL).
Bishop Score
- Maximum score: 13
- < 5 indicates an unfavorable cervix for IOL, and IOL is unlikely to be successful.
- ≥ 6 indicates a favorable cervix for IOL.
- ≥ 9 indicates a high likelihood of vaginal delivery similar to spontaneous labor.
Simplified Bishop Score
- Focuses just on cervical dilation, effacement, and fetal head station.
- Maximum score: 9.
Modified Bishop Score
- Replaced the position of cervix with the length of the cervix (measured by ultrasound).
Methods of Induction of Labor
-
Cervix Ripening:
- Sweeping membranes
- Mechanical methods (Foley's catheter, EASI, hydroscopic dilators)
- Prostaglandins
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IOL:
- Mechanical methods
- Prostaglandins
- Oxytocin
-
Augmentation:
- Oxytocin
- ARM (Artificial Rupture of membranes)
Sweeping of Membranes
- AKA: Stripping of membranes.
- Indication: Slightly dilated cervix.
- Principle: Sweeping membranes detaches them from the cervix, releasing prostaglandins and ripening the cervix.
Augmentation of Labor
- Artificial rupture of membranes (ARM) is a key method.
- Instrument: Kocher's forceps (single tooth, multiple rat-like teeth, ratchet lock, transverse serrations).
Principle of ARM
- Rupture of membranes releases PGE2, augmenting labor.
Contraindications for ARM
-
Absolute:
- Maternal HIV
- Genital herpes infection
- Intrauterine device (IUD)
-
Relative:
- Polyhydramnios (increased risk of abruptio placenta)
Controlled Rupture of Membranes
- A slow release of amniotic fluid is achieved by making a small hole in the membrane.
Note
- ARM is beneficial in abruptio placenta because it confirms the diagnosis and accelerates the process of labor.
Indications for Augmentation of Labor
- Slow progress of labor: Cervical dilation less than 1 cm/hour in the active phase.
Sequence of Augmentation
- If head engaged: ARM followed by oxytocin.
- If head not engaged: Oxytocin (increased risk of cord prolapse).
Cardinal Movements of Labor
- Engagement
- Descent
- Flexion
- Internal rotation & crowning
- Extension (Delivery of head)
- External Rotation (Restitution)
- Expulsion of body
Dinoprostone (PGE₂)
- Cerviprime gel:
- Dose: 0.5 mg
- Injected into the cervix
- Repeat every 6 hours
- Maximum of 3 doses
- Refrigerated
- Cervidil:
- Dose: 10 mg
- Release: 0.3 mL/hr
- Inserted: Posterior fornix, kept in vagina
- 12 hours until labor onset
Oxytocin
- Use directly if the cervix is ripe.
- Ripen the cervix with other methods if it is not ripe, then use oxytocin.
- Administration:
- Inserted into the posterior fornix, kept in vagina
- 5 units Oxytocin in 500 mL Normal Saline
- Maximum dose: 52 drops/min (26 mIU/mL)
- Water intoxication (hyponatremia) can occur if dissolved in 5% dextrose.
- Hypotension can occur if the drop rate is increased.
Contraindications for IOL
- Conditions where vaginal delivery is contraindicated include:
- Placenta previa and vasa previa
- Malpresentation (transverse lie, brow, mentoposterior face)
- Active genital herpes
- Contracted pelvis
- CPD (Cephalopelvic Disproportion)
- Cancer cervix
- Previous history of myomectomy
- Fetal distress
- Monochorionic monoamniotic twins or conjoined twins
IOL in Special Cases
- Scarred uterus: Mechanical methods for ripening followed by oxytocin.
-
IUD of Fetus:
- 20-28 weeks: Misoprostol 600-800 mcg PV, repeat 400mg every 3 hours.
-
28 weeks: 25mg Misoprostol (ripen cervix) followed by oxytocin.
Engagement
- The largest transverse diameter of the fetal head (biparietal diameter) crosses the pelvic inlet.
- Occurs at 38 weeks in primigravida and at the onset of labor in multigravida.
Signs of Engagement
- On P/A examination: ≤ 5/5th of the head palpable.
- On P/V examination: 0 station.
Causes of Unegagement in Primigravida at Term
- Deflexed head is the most common cause, followed by cephalopelvic disproportion and placenta previa.
- Other causes: polyhydramnios and wrong dates.
Note
- Placenta previa must be ruled out before a P/V examination in primigravida with a free-floating head.
- Engagement rules out cephalopelvic disproportion (CPD) at the level of the inlet.
Engaging AP Diameter
- The engaging AP diameter depends on the degree of flexion of the fetal head.
| Degree of flexion | Presenting part | Engaging AP diameter |
|---|---|---|
| 1. Fully flexed | Vertex | Sub-occipitobregmatic |
| 2. Deflexed | Vertex | Occipito-frontal (11.5cm) |
| 3. Partially extended | Brow | mento-vertical (11cm) |
| 4. Fully extended | Face | C-sectionSubmento-vertical & Submento-bregmatic |
Synclitic engagement
- The sagittal suture of the fetal head is aligned with the transverse diameter of the pelvis, midway between the pubic symphysis and sacral promontory (in LOT position).
Step 1: Injection of Uterotonics
WHO Recommendation
- Inj Oxytocin: 10 IU by IM or IV infusion (in Ringer Lactate/Normal saline).
- Storage: 2 to 8°C.
-
Contraindications:
- IV bolus administration
- Dextrose 5% preparation (due to possibility of water intoxication)
-
Water Intoxication (due to anti-diuretic effect):
- Hypotension
- Tachycardia
- Cardiac arrhythmias
- Cardiac arrest
If Oxytocin Unavailable
- 1. Methylergometrine: 0.2 mg IM (IV avoided due to severe hypertension).
- Storage: Room temperature.
- 2. Syntometrine: Fixed dose combination of oxytocin and 0.5mg methylergometrine.
- Advantage: Increased efficacy.
- Disadvantage: Expensive and low availability.
-
3. Carboprost: Synthetic oxytocin (Octapeptide).
- Dose: 100 mcg slow IV over 1 min.
- Time to act: 40 mins (longer than oxytocin with a half-life of 3 to 5 mins)
- Duration of action: 3 hrs (Not used for induction/augmentation of labor or PPH management).
-
4. Misoprostol (PGE1):
- Dose: 600 mcg tablets orally/sublingual (Range: 400 to 600 mcg).
Differences Between Oxytocin & Methylergometrine
| Feature | Oxytocin | Methylergometrine |
|---|---|---|
| Type of contractions | Physiological: Occurs at regular intervals + Relaxation between for blood flow to fetus | Tetanic contractions + No relaxation (may cause fetal distress) |
| Acts on | Lower and upper uterine segments | Lower uterine segment mainly |
| Use | Induction of labor Augmentation of labor Preferred for AMTSL Hypotension (with IV bolus) | Only after delivery of baby Not first line in AMTSL (D/t ↑ chance of retained placenta) Hypertension |
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Description
Explore the critical aspects of the third stage of labour, including the methods of placental separation and management strategies. Learn about the differences between passive and active management, and the importance of uterine contractions in placental delivery. This quiz covers key concepts and procedures that ensure maternal safety and reduce the risk of complications.
