Learn — Abnormal labour & obstetric emergencies

5 notes · 46 questions on the topic

Cord prolapse

Cord prolapse is descent of the umbilical cord below the presenting part after the membranes have ruptured — overt when the cord lies in the vagina or outside the introitus, occult when it lies beside the presenting part; the same descent with intact membranes is called cord presentation. It is an immediate emergency because the presenting part compresses the cord and the exposed vessels go into spasm in cold air, so the fetus can die within minutes.

Incidence is about 1 in 300–500 births. Risk factors: malpresentation (breech, especially footling, and transverse lie), polyhydramnios, prematurity and low birth weight, multiple pregnancy, a high or unengaged presenting part, a long cord, low-lying placenta, and artificial rupture of membranes at a high station.
Diagnosis: a pulsating cord felt on vaginal examination or seen at the introitus, together with a sudden fetal bradycardia or variable decelerations immediately after the membranes rupture. Always examine vaginally after rupture when the presenting part is high.
First actions: call for help, stop any oxytocin, and take the pressure off the cord — put her in the knee–chest position or exaggerated Sims (left lateral, head down, hips raised on pillows) and keep a gloved hand in the vagina pushing the presenting part up off the cord until delivery.
Filling the bladder with 500–750 mL of warm saline through a Foley catheter lifts the presenting part when the transfer or theatre wait will be long; the catheter must be unclamped before the caesarean.
Handle the cord as little as possible and keep it warm and moist with a saline-soaked pad; replacing it into the uterus is not recommended.
Give the mother oxygen by mask, consider a tocolytic (terbutaline 250 µg subcutaneously) if the uterus is contracting, and monitor the fetal heart continuously.
Definitive treatment is immediate delivery: a category-1 caesarean with a decision-to-delivery interval under 30 minutes, or an assisted vaginal delivery when the cervix is fully dilated and the head is low enough for that to be faster.
Prevention: never rupture membranes when the presenting part is high or mobile, and examine on admission for a cord in any woman with ruptured membranes and a malpresentation. Have the neonatal team at the delivery and send cord blood gases.

Shoulder dystocia — McRoberts manoeuvre

Shoulder dystocia is a vaginal cephalic birth in which the shoulders fail to deliver with routine axial traction after the head is born, because the anterior shoulder is impacted behind the pubic symphysis (rarely the posterior shoulder on the sacral promontory). It is a bone-against-bone obstruction, complicates about 0.6% of vaginal births, and threatens the baby with hypoxia, brachial plexus injury and fracture while it exposes the mother to postpartum haemorrhage and severe perineal tears.

Diagnosis: the turtle sign — the head delivers and then retracts tightly against the perineum — with failure of restitution and failure of the shoulders to deliver with routine traction.
HELPERR: call for Help; Evaluate for episiotomy; Legs into McRoberts; suprapubic Pressure; Enter the pelvis for internal rotation; Remove the posterior arm; Roll the woman onto all fours.
McRoberts is the first manoeuvre and relieves about half of cases on its own: hyperflex and abduct both thighs onto the abdomen, which straightens the lumbosacral angle and rotates the symphysis upwards over the impacted shoulder.
Add suprapubic pressure (Rubin I) — steady, then rocking, applied from the side of the fetal back and directed downwards and laterally to push the anterior shoulder into the oblique diameter. McRoberts with suprapubic pressure resolves the great majority.
Never apply fundal pressure: it drives the shoulder harder onto the symphysis and can rupture the uterus. Do not pull hard, twist the neck or flex it laterally — that is what tears the brachial plexus.
Internal manoeuvres in order: Rubin II (push the anterior shoulder towards the fetal chest), Woods screw (rotate the posterior shoulder 180°), reverse Woods, then delivery of the posterior arm — the most effective step when rotation fails — and finally the all-fours (Gaskin) position.
Last-resort measures are cleidotomy, symphysiotomy and the Zavanelli manoeuvre (replacing the head and delivering by caesarean); all carry high maternal and fetal morbidity.
Risk factors are macrosomia, maternal diabetes at any birth weight, obesity, a previous shoulder dystocia, prolonged second stage and instrumental delivery — but half of cases have no risk factor at all, so every birth attendant must be able to do McRoberts.
Afterwards: examine the baby for Erb's palsy, clavicular or humeral fracture and hypoxic injury, examine the mother for postpartum haemorrhage and third or fourth-degree tear, and document the times, the manoeuvres used, who was present and the head-to-body interval.

Postpartum haemorrhage — management and risk factors

Primary postpartum haemorrhage is blood loss of ≥500 mL after vaginal birth, ≥1000 mL after caesarean, or any loss causing haemodynamic instability, within 24 hours of delivery; secondary postpartum haemorrhage is abnormal bleeding from 24 hours to 12 weeks after birth. It is the leading direct cause of maternal death in India, and an atonic uterus accounts for 70–80% of it — which is why every birth, not every risky birth, gets a uterotonic in the third stage.

The 4 Ts: Tone (atony, 70–80%), Trauma (perineal, vaginal or cervical tears, uterine rupture, inversion), Tissue (retained placenta, cotyledon or membranes) and Thrombin (coagulopathy from abruption, sepsis, HELLP or amniotic fluid embolism).
First response: call for help, rub up a contraction, empty the bladder, insert two wide-bore cannulae, send blood for grouping, cross-match and coagulation, and give oxytocin 10 IU IM or slow IV at once, then 20 IU in 1 L crystalloid at 60 drops/min continuing at 40 drops/min — not more than 3 L of oxytocin-containing fluid.
Methylergometrine 0.2 mg IM or slow IV, repeated after 15 minutes and then every 4 hours to a maximum of 5 doses (1 mg) — contraindicated in hypertension, pre-eclampsia and heart disease.
Carboprost 250 µg IM, repeated every 15–90 minutes to a maximum of 8 doses (2 mg) — contraindicated in asthma. Misoprostol 800 µg sublingual, or 800–1000 µg per rectum, where injectable uterotonics are unavailable.
Tranexamic acid 1 g IV over 10 minutes as early as possible and within 3 hours of onset, repeated once after 30 minutes if bleeding continues; given after 3 hours it does not work.
Mechanical measures while the drugs act: bimanual uterine compression, aortic compression, uterine balloon tamponade (a condom catheter inflated with 250–500 mL of saline), and the non-pneumatic anti-shock garment for transfer.
Surgical escalation without delay: examination under anaesthesia with repair of tears, manual removal of a retained placenta, B-Lynch or other compression suture, stepwise uterine and ovarian artery ligation, internal iliac ligation, and hysterectomy as the life-saving last step.
Massive transfusion in a 1:1:1 ratio of packed cells, fresh frozen plasma and platelets; keep her warm, watch for the lethal triad of hypothermia, acidosis and coagulopathy, and keep fibrinogen above 2 g/L.
Secondary postpartum haemorrhage is usually retained products or endometritis: ultrasound, broad-spectrum antibiotics and gentle evacuation once the antibiotics are running.

Breech manoeuvres — Lovset, Burns-Marshall

Assisted breech delivery is the set of manoeuvres used when a breech-presenting fetus is delivered vaginally: the fetus is allowed to deliver spontaneously as far as the umbilicus, and the operator then helps with the arms and the after-coming head. The head is the danger — it is the largest, last and least mouldable part, and it must be delivered flexed and slowly, which is why the rule is hands off the breech until the scapulae are seen.

Hands off the breech until the scapula is visible: traction before that extends the arms behind the neck (nuchal arms) and extends the head, turning an assisted breech into a difficult one.
Løvset's manoeuvre delivers extended or nuchal arms — hold the fetus by the bony pelvis (never the abdomen), rotate the trunk 180° keeping the back uppermost so that the posterior shoulder becomes anterior under the pubic arch, sweep that arm down, then rotate 180° the other way and deliver the second arm.
Burns–Marshall method delivers the after-coming head by flexion: let the body hang for 1–2 minutes until the nape of the neck and the hairline appear, then grasp the ankles and sweep the trunk in a wide arc over the mother's abdomen while the other hand guards the perineum, delivering the head slowly.
Mauriceau–Smellie–Veit manoeuvre (jaw flexion with shoulder traction): the fetus straddles the operator's forearm and the index and ring fingers of that hand rest on the malar bones — the maxilla — with the middle finger on the chin to keep the head flexed, while two fingers of the other hand hook over the shoulders and apply downward traction. Fingers are never placed inside the mouth, which would dislocate or fracture the mandible.
Pinard's manoeuvre delivers an extended leg in a frank breech: press behind the knee to abduct and flex the thigh, then sweep the leg down across the abdomen.
Piper or long-handled forceps applied to the after-coming head is the controlled alternative when the head does not deliver; the assistant holds the body horizontal and never above the horizontal, which would hyperextend the neck.
Prerequisites for a vaginal breech: an experienced operator, a frank or complete (not footling) breech, an estimated weight of about 2–3.5 kg, a flexed head, an adequate pelvis, no placenta praevia, continuous fetal monitoring and immediate access to theatre.
External cephalic version is offered from 36 weeks in nulliparous and from 37 weeks in multiparous women when there is no contraindication (antepartum haemorrhage, ruptured membranes, multiple pregnancy, fetal compromise); anti-D is given afterwards to Rh-negative women.
Complications: cord prolapse (highest in a footling breech), entrapment of the after-coming head in an incompletely dilated cervix, nuchal arms, fractures of the humerus or clavicle, brachial plexus injury, and intracranial haemorrhage from rapid delivery of the head.

Instruments for curettage and caesarean section

NORCET's image-based questions ask you to name an obstetric instrument and say what it is used for, so the trays are learnt as sets rather than as isolated pictures. The dilatation-and-curettage tray is built around exposing the cervix, dilating it and emptying the uterus, while the caesarean tray is built around retracting the bladder, holding the uterine incision and controlling its bleeding edges.

Dilatation and curettage tray: Sims' double-bladed speculum with an anterior vaginal wall retractor, anterior vulsellum or tenaculum to steady the cervix, a uterine sound, Hegar's dilators graded from about 4 to 16 mm, blunt and sharp curettes, ovum and sponge-holding forceps, and a kidney tray for the tissue.
Manual vacuum aspiration set: a 60 mL double-valve syringe with Karman cannulae of 4–12 mm — the cannula size is chosen to match the gestation in weeks — used up to 12 weeks; it needs no electricity and far less cervical dilatation.
Caesarean section tray: scalpel, Doyen's retractor for the bladder, a Balfour or Morris self-retaining retractor, Allis and Babcock forceps, Green–Armytage forceps (the classic image question — atraumatic haemostatic clamps applied to the bleeding edges of the uterine incision), ovum forceps, artery forceps, needle holders and a cord clamp.
Labour-room instruments: Kocher's forceps for artificial rupture of membranes, episiotomy and cord scissors, a mucus extractor, Wrigley's outlet forceps, Das's or Simpson's obstetric forceps, and silastic or metal ventouse cups.
All of these are critical items in Spaulding's classification because they enter sterile tissue, so they are autoclaved at 121 °C and 15 psi for 15–20 minutes; the swab and instrument count is done before the abdomen or the perineum is closed and again at the end.
Dilate only to the size the gestation requires and sound the uterus gently — perforation is the commonest instrumental complication, and a sudden loss of resistance during dilatation means stop and reassess.

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