OG14.1-3,OG15.1-2 | Abnormal and Operative Obstetrics — Graded Quiz

Correct. A short-statured woman (height ≤150 cm is a risk factor for contracted pelvis), adequate contractions crossing the action line, and persistently unengaged head despite good contractions point to cephalopelvic disproportion as the mechanism — a mechanical obstruction. Functional dystocia implies inadequate contractions, which are good here.

Cephalopelvic disproportion vs functional dystocia: adequate contractions (≥3 in 10 min, ≥45 sec) + arrest of descent = mechanical obstruction. Inadequate contractions + slow progress = functional dystocia (augment with oxytocin). Short stature (≤150 cm) is a clinical risk marker for contracted pelvis.

With 3 contractions in 10 min each >45 seconds, power is adequate — ruling out functional/hypotonic dystocia. A height of 148 cm is a known risk marker for contracted pelvis. Head at -2 station despite good contractions and action-line crossing = mechanical obstruction (CPD). Cervical dystocia or scar tissue are rare and not suggested by this history.

Correct. VVF after obstructed labour results from sustained ischaemic pressure necrosis: the fetal head presses the anterior vaginal wall and bladder trigone against the posterior surface of the pubic symphysis for hours, leading to avascular necrosis that sloughs 3-5 days postpartum. This is the classic obstetric fistula mechanism, preventable only by timely delivery.

Obstetric fistula mechanism: prolonged obstructed labour → sustained ischaemic pressure on bladder/vaginal wall between fetal head and pubic symphysis → avascular necrosis → sloughing 3-7 days postpartum → VVF (anterior) or rectovaginal fistula (posterior). Prevention = timely CS for obstructed labour.

Obstetric VVF is caused by ischaemic pressure necrosis from prolonged mechanical compression between the presenting part and bony pelvis — NOT surgical injury (unless there was a specific operative complication), NOT UTI alone, and NOT oxytocin. The fistula presents 3-7 days after delivery when the necrotic tissue sloughs. This is the most common cause of VVF in developing countries.

Correct. The triad of sudden severe abdominal pain, haemodynamic shock, fetal heart absent, and recession of the presenting part (it has retracted into the abdominal cavity) is pathognomonic of complete uterine rupture. Grand multiparity is a known risk factor (thin, over-distended myometrium). Immediate simultaneous resuscitation + emergency laparotomy is mandatory.

The pathognomonic sign of uterine rupture is recession of the presenting part — it 'rises' because the fetus is extruded through the rupture into the peritoneal cavity. This is accompanied by cessation of contractions, sudden pain, and haemodynamic collapse. Grand multiparity is a major risk factor for unscarred uterine rupture.

Recession of the presenting part (the fetal head 'rising' back into the abdomen above the pelvic brim) is the PATHOGNOMONIC sign of uterine rupture — the baby has been partially or completely extruded into the peritoneal cavity. This distinguishes it from abruption (presenting part stays in position) and cord prolapse (presenting part remains, cord felt on VE). Immediate laparotomy is required.

Correct. A thin translucent window without breach of membranes or haemorrhage is scar dehiscence (incomplete rupture) — the peritoneum/serosa is intact. It is surgically repaired at the time of CS (not hysterectomy unless haemostasis is uncontrollable). The patient must be counselled that future pregnancy carries high rupture risk.

Scar dehiscence (incomplete rupture) = thin/transparent LUS, peritoneum intact, no haemorrhage. Found incidentally at CS. Management: surgical repair + sterilisation counsel for high-risk future pregnancies. Complete rupture = all layers breached, haemorrhage, fetus at risk. The distinction determines urgency and surgical approach.

A scar 'window' (thin translucent LUS without peritoneal breach or haemorrhage) is incomplete scar dehiscence, not complete rupture. Hysterectomy is not indicated for a repairable finding in a stable patient. It must be surgically repaired (not ignored or left to antibiotics). B-Lynch suture is for postpartum haemorrhage, not scar repair. Repair + counselling is the correct approach.

Correct. Face presentation is identified by palpating the mouth, nose, and orbital ridges. The denominator in face presentation is the mentum (chin). Mentoposterior (chin pointing towards the sacrum or a posterior position) means the fetal neck is already maximally extended — further extension is impossible, and flexion to negotiate the pelvis cannot occur. Vaginal delivery is NOT possible in a persistent mentoposterior; CS is required.

Face presentation denominator = mentum. Key rule: mentoanterior → vaginal delivery possible (chin rotates under symphysis, head flexes). Mentoposterior → CS required (fully extended head, further extension not possible, cannot flex to deliver). Always determine the chin position before planning delivery route.

Brow presentation has orbital ridges + frontal suture palpable (not mouth/nose/chin). In face presentation, mentoanterior (chin anterior, pointing towards pubic symphysis) allows vaginal delivery because the chin can rotate under the pubic arch. Mentoposterior means the chin is posterior — the extended head cannot flex to deliver the face — vaginal delivery is impossible. The key rule is: mentoanterior = can deliver vaginally; mentoposterior = CS required.

Correct. In term transverse lie with early labour, ECV is the first-line approach — it is safe, minimally invasive, and if successful allows vaginal delivery. Tocolysis (usually terbutaline) facilitates version. If ECV fails or is contraindicated, CS is performed. Transverse lie never self-corrects once labour is established (shoulder dystocia at the outlet would result). Internal podalic version is dangerous in early labour with intact membranes.

Transverse lie at term in early labour: attempt ECV under tocolysis first (provided no contraindications). If ECV fails or contraindicated → CS. Transverse lie NEVER delivers vaginally at term without conversion. Internal podalic version for transverse lie is reserved for second twins, not term singletons.

Transverse lie at term does NOT self-correct in labour — the shoulder or arm will prolapse, causing neglected shoulder presentation and obstructed labour. ECV under tocolysis is the correct approach before resorting to CS. Internal podalic version is restricted to the second twin after delivery of the first or under general anaesthesia in specific scenarios — NOT first-line for a singleton in early labour.

Correct. The 'rule of threes' for vacuum: abandon after three pulls without descent, or two cup detachments, or 15-20 minutes total. With recurrent late decelerations indicating fetal compromise, immediate CS is required. Sequential instrumental delivery (vacuum then forceps) substantially increases neonatal morbidity and should be avoided except in very specific circumstances with an experienced operator.

Abandon vacuum and proceed to CS if: no descent after 3 pulls, 2 cup detachments, >15-20 min of traction, or any evidence of fetal compromise at any point. Do NOT routinely proceed to forceps after failed vacuum — sequential instrumental delivery carries very high fetal morbidity risk.

Failure to advance after three traction attempts is an indication to abandon and proceed to CS, not to switch instruments or increase pressure. Sequential use of vacuum then forceps dramatically increases the risk of fetal cranial injury and intracranial haemorrhage. With superimposed fetal distress (late decelerations), immediate CS is the only safe option.

Correct. Classical (upper uterine segment) caesarean section is a contraindication to trial of labour (VBAC). The upper segment scar involves active contractile myometrium with a much higher rupture rate (~4-9%) compared to LSCS scar (~0.5-1%). A previous CS for breech is a non-recurrent indication and is compatible with VBAC trial.

VBAC contraindication: classical (upper segment) CS scar, previous uterine rupture, two or more previous CS (relative), previous vertical LUS incision (T or J incision). Previous LSCS for a non-recurrent indication (breech, fetal distress) is compatible with VBAC trial in an appropriately equipped facility with continuous monitoring.

Previous CS for breech is a non-recurrent indication — the current presentation is vertex with no CPD, so VBAC is appropriate. Classical CS scar (vertical upper-segment incision) has a rupture risk of 4-9% in labour (vs 0.5-1% for LSCS), making labour in that uterus contraindicated. Gestational diabetes on diet control and a favourable Bishop score are not contraindications to VBAC.

Correct. Bladder reflection (creation of the bladder flap) displaces the bladder inferiorly away from the incision line on the lower uterine segment, protecting it from inadvertent cystotomy when the uterus is incised. It also facilitates closure of the uterine incision and reduces blood loss from the bladder pillars.

The bladder flap in LSCS: incise the utero-vesical peritoneal fold → reflect bladder downwards → protects bladder from cystotomy during the transverse uterine incision. The lower uterine segment incision is then made 1-2 cm above the reflected bladder edge, giving adequate safe clearance.

Bladder reflection has a specific protective purpose: it moves the bladder away from the planned uterine incision site on the lower segment, preventing bladder injury during uterine entry. Ureteric access, vesicovaginal space entry, and uterine sinus haemostasis are not the purpose of the bladder flap. Cystotomy during CS, though uncommon, is a known complication averted by this step.

Correct. Early secondary repair (resuture within 3-5 days of dehiscence) in the absence of infection has good outcomes and is preferred over prolonged healing by secondary intention, which leads to poor cosmesis, dyspareunia, and perineal weakness. The wound must be clean and non-infected before resuturing.

Episiotomy dehiscence management: if non-infected and wound edges are viable → early secondary repair under LA (within 3-5 days). If infected → wound toilet, antibiotics, debridement, then secondary repair when clean. Healing by secondary intention for a complete dehiscence leads to perineal weakness and long-term dyspareunia.

Non-infected episiotomy dehiscence within the first few days should be managed by early secondary repair — not waiting 6 weeks, not leaving to heal by secondary intention alone, and not requiring prolonged IV antibiotics before repair. If there is infection, debridement and antibiotic cover are given first, then repair after the wound is clean (usually 3-5 days).

Correct. Lithotomy position is mandatory for forceps delivery (handles cannot be brought to horizontal without this). An empty bladder (catheterisation) is a non-negotiable prerequisite to avoid bladder injury from the blades. These prerequisites cannot be deferred — they must be confirmed BEFORE blade application.

Non-negotiable prerequisites before any instrumental delivery: patient in dorsal lithotomy position, bladder catheterised (empty), adequate analgesia in place, position of fetal head confirmed. These cannot be deferred. Part of the observer/assistant role is to confirm these safety steps are completed before the procedure begins.

Lithotomy position and bladder catheterisation are mandatory prerequisites for forceps delivery, not optional. They apply equally to forceps and vacuum. Even with fetal distress, these 30-second prerequisites must be done — proceeding without them risks bladder injury and failed application. As the assisting doctor, flagging missed prerequisites is a patient safety responsibility.

Correct. ECV at term has an average success rate of approximately 50-60% (range 30-80% depending on parity, experience, tocolysis use). It reduces CS rates for breech by approximately 50%. Reversion to breech after successful ECV occurs in 1-3% of cases, hence position should be confirmed at follow-up visits.

ECV at term: overall success ~50-60% (higher in multiparas, with tocolysis, posterior placenta, adequate liquor). Reduces breech-related CS rate by ~50%. Reversion rate ~1-3% — always confirm position at later visit. Complications (placental abruption, fetal bradycardia) occur in <1% — CTG monitoring before and after is mandatory.

ECV success rate is approximately 40-60%, NOT 90-95%. Success is higher in multiparas (relaxed uterus) and with tocolysis. Even after successful ECV, 1-3% of fetuses revert to breech before labour — confirming position at 38+ weeks is standard practice. Primigravidas can benefit from ECV (though success rate is lower than in multiparas, it is well above 20%).