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OG10.1-2,OG11.1 | Late Pregnancy Complications — Graded Quiz
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A 32-year-old G2P1 at 36 weeks presents with sudden, severe, constant lower abdominal pain and heavy vaginal bleeding. On examination: BP 90/60 mmHg, pulse 120 bpm, uterus is tense and exquisitely tender, fetal heart sounds are absent. The hemoglobin is 6.5 g/dL. Which of the following is the MOST appropriate immediate next step?
Correct. This presentation is classic for severe placental abruption with fetal death. The immediate priorities are haemodynamic resuscitation (large-bore IV, crystalloid, blood products) and emergency caesarean section. Digital vaginal examination is dangerous if praevia has not been excluded; however, given the haemodynamic instability and absent fetal heart tones, resuscitation and delivery take precedence over further USS. Tocolytics are absolutely contraindicated in abruption.
Severe abruption = resuscitate and deliver emergently. Tocolytics are absolutely contraindicated. Tense, board-like uterus + haemodynamic shock + absent fetal heart sounds = classic massive concealed abruption.
Severe abruption with haemodynamic compromise and fetal death requires immediate IV access, resuscitation, and emergency delivery — NOT digital VE (dangerous if praevia not excluded), NOT USS first (clinical diagnosis is clear), NOT tocolytics (contraindicated in abruption).
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A routine anomaly scan at 20 weeks in a primigravida shows a low-lying posterior placenta with its lower edge reaching the internal os. She has no bleeding. What is the MOST appropriate next step in management?
Correct. Low-lying placenta at the 20-week anomaly scan is common and frequently resolves due to differential growth of the lower uterine segment (placental migration). The correct management is to reassure and schedule a repeat transvaginal USS at 32-34 weeks. Bed rest is not evidence-based; immediate caesarean planning at 34 weeks is premature without confirming persisting praevia.
Apparent low-lying placenta at 20 weeks does not equal confirmed praevia — lower uterine segment growth causes apparent upward migration. Repeat TVS at 32-34 weeks before making delivery plans.
Low-lying placenta at 20 weeks often 'migrates' as the lower uterine segment grows. A repeat TVS at 32-34 weeks is standard practice to confirm whether true praevia persists. Immediate bed rest or early delivery planning is not indicated without persisting praevia and/or bleeding.
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Vasa praevia is suspected when Doppler USS shows fetal blood vessels running across the internal os. The event most immediately life-threatening to the fetus in this condition is:
Correct. In vasa praevia, the fetal blood vessels cross the internal os within the membranes. Rupture of membranes (spontaneous or artificial) tears these vessels, causing rapid fetal exsanguination — fetal blood loss, not maternal. The fetal blood volume is only ~250-300 mL at term, so even 50-100 mL loss is immediately life-threatening. Perinatal mortality exceeds 50% if unrecognised.
Vasa praevia = fetal vessels cross the os within membranes. Membrane rupture = fetal exsanguination (fetal blood, not maternal). Perinatal mortality >50% if undiagnosed. Elective pre-labour caesarean section at 35-36 weeks is recommended after antenatal diagnosis.
The unique danger of vasa praevia is fetal exsanguination when membranes rupture (the blood lost is fetal blood). Maternal DIC and cord prolapse are complications of other conditions. Placental infarction does not directly cause acute haemorrhage.
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A patient undergoing emergency caesarean section for placenta praevia accreta receives 12 units of PRBCs over 2 hours (massive transfusion). Coagulation screen: PT 22 s, aPTT 55 s, fibrinogen 1.0 g/L, platelets 85,000/µL. In addition to cryoprecipitate, what is the MOST appropriate blood product component to administer for the coagulopathy?
Correct. Massive transfusion causes dilutional coagulopathy because PRBCs contain no clotting factors. FFP contains all labile clotting factors (V, VIII) and is the appropriate replacement for a prolonged PT and aPTT in the absence of specific factor deficiency. A 1:1:1 ratio of PRBCs:FFP:platelets is the standard massive transfusion protocol in damage-control haemostasis. Cryoprecipitate additionally addresses the fibrinogen deficit.
Massive transfusion protocol: 1:1:1 ratio of PRBCs:FFP:platelets. FFP corrects dilutional factor deficiency; cryoprecipitate corrects fibrinogen deficit (target fibrinogen >2 g/L in obstetric haemorrhage).
Massive transfusion causes dilutional coagulopathy — clotting factors are lost because PRBCs have none. FFP replaces all clotting factors and is standard in the 1:1:1 MTP ratio. Vitamin K acts only on vitamin-K-dependent factors and takes hours; protamine reverses heparin (not relevant here).
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A patient develops dyspnoea, hypoxia, and bilateral infiltrates on chest X-ray within 2 hours of receiving packed red blood cells. She has no fluid overload, no pre-existing cardiac disease, and her pulmonary artery wedge pressure is normal. The MOST likely diagnosis is:
Correct. TRALI is defined as new acute lung injury (hypoxia + bilateral infiltrates) within 6 hours of a blood product transfusion, NOT explained by a pre-existing ALI, with no evidence of circulatory overload (normal PCWP ≤18 mmHg). It is mediated by donor anti-leukocyte antibodies or biologically active lipids activating recipient neutrophils in the pulmonary vasculature.
TRALI vs TACO: both cause respiratory failure post-transfusion. TRALI = normal PCWP (non-cardiogenic), no fluid overload. TACO = elevated PCWP, responds to diuretics. Management of TRALI: supportive (oxygen, ventilation if needed); no specific antidote.
TRALI = acute lung injury within 6 hours of transfusion, no circulatory overload, normal PCWP. TACO = fluid overload pattern (elevated PCWP, responds to diuretics). DHTR occurs days to weeks later. AHTR involves haemolysis, not respiratory failure.
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Before performing a non-emergency blood transfusion, which pre-transfusion testing sequence is CORRECT?
Correct. Pre-transfusion testing follows the sequence: (1) ABO and Rh(D) typing of recipient blood, (2) antibody screen to detect unexpected alloantibodies, and (3) crossmatch (major crossmatch: donor cells + recipient serum) to confirm compatibility between the specific donor unit and recipient. This sequence ensures compatibility at every level.
Pre-transfusion testing: ABO/Rh typing → unexpected antibody screen → major crossmatch. In a life-threatening emergency where there is no time, O-negative (universal donor) PRBCs are given empirically.
The correct pre-transfusion sequence is ABO/Rh typing → antibody screen → crossmatch. The crossmatch is the final compatibility verification specific to the donor unit chosen; it cannot replace typing and antibody screening.
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A 30-year-old primigravida at 22 weeks has MCDA twins on serial ultrasounds. She is noted to have one twin with oligohydramnios (DVP <2 cm) and the other with polyhydramnios (DVP >8 cm), with discordant bladder filling. The Quintero staging system grades this as Stage II if:
Correct. Quintero staging of TTTS: Stage I = oligopolyhydramnios sequence but donor bladder visible; Stage II = donor bladder NOT visualised (stuck twin — severe oliguria indicating renal hypoperfusion); Stage III = critically abnormal Doppler indices (absent/reversed end-diastolic flow or reversed ductus venosus flow); Stage IV = hydrops; Stage V = fetal demise.
Quintero TTTS staging: I (oligopoly, bladder visible) → II (donor bladder absent/stuck twin) → III (abnormal Dopplers) → IV (hydrops) → V (death). Treatment is laser ablation of anastomoses (fetoscopic laser photocoagulation) for Stage II-IV.
Quintero Stage II TTTS is defined by non-visualisation of the donor twin's bladder (stuck twin). Stage I = bladder still visible. Stage III = critically abnormal Dopplers. Stage IV = hydrops. Stage V = demise.
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A patient with DCDA twins at 36 weeks has twin A in vertex presentation and twin B in breech. She has no complicating factors, an adequate pelvis, and EFW of both twins is approximately 2.5 kg each. The MOST appropriate management plan is:
Correct. For DCDA twins with twin A vertex, vaginal delivery is a reasonable option. After delivery of twin A, twin B's presentation should be reassessed intrapartum; external cephalic version or internal podalic version for non-vertex twin B followed by assisted breech delivery or caesarean section are all options. Elective caesarean is not mandatory for uncomplicated DCDA twins with vertex presentation of twin A. Delivery timing for uncomplicated DCDA twins is typically 37-38 weeks.
DCDA twins with vertex twin A: vaginal delivery acceptable. MCDA: delivery at 36-37 weeks. MCMA: deliver at 32-34 weeks (cord entanglement risk). Chorionicity determines surveillance interval and delivery timing.
Elective caesarean is NOT mandatory for all twins. DCDA twins with vertex twin A can have a trial of vaginal labour. Optimal delivery timing for uncomplicated DCDA is 37-38 weeks — deferring to 39+ weeks increases placental insufficiency risk.
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A dizygotic twin pregnancy has two separate placentas and two separate chorionic sacs. What is the expected risk of twin-to-twin transfusion syndrome (TTTS) in this pregnancy?
Correct. TTTS is caused by unbalanced arterio-venous anastomoses within a shared monochorionic placenta. Dizygotic twins are ALWAYS dichorionic (they develop from two separate eggs and sperm). Dichorionic placentas, even if anatomically fused, do NOT share intraplacental vascular anastomoses — therefore TTTS is impossible. The risk is exactly zero.
Dizygotic = always DCDA = no shared placental vasculature = TTTS impossible. TTTS risk is exclusive to monochorionic twins (10-15% of MCDA twins develop TTTS).
TTTS requires intraplacental arterio-venous anastomoses, which only exist in monochorionic placentas. Dizygotic twins are invariably dichorionic — they have two separate placentas with no shared vasculature. TTTS risk is zero, not merely low.
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In the management of major placenta praevia (type III/IV) at term with active haemorrhage, the safest mode of delivery is:
Correct. Major placenta praevia (type III: partially covering the os; type IV: centrally covering the os) is an absolute indication for caesarean section. Vaginal delivery would require the fetus to be delivered through the placenta, causing catastrophic haemorrhage. The operation should be performed by a senior obstetrician with blood products (including FFP, cryoprecipitate, platelets) available and a cell saver considered.
Type III/IV placenta praevia = absolute indication for caesarean section. Pre-operative preparation: blood products, senior surgeon, possible balloon occlusion/cell saver if accreta suspected.
Major placenta praevia (type III/IV) is an absolute indication for caesarean section — vaginal delivery, instrumental delivery, and ECV are all contraindicated. Praevia covering the internal os obstructs the birth canal; attempting vaginal delivery would cause the fetus to be delivered through the placenta with catastrophic bleeding.
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In obstetric massive haemorrhage with evolving disseminated intravascular coagulation, the fibrinogen level to TARGET before considering the haemorrhage controlled is:
Correct. In obstetric haemorrhage with DIC, the target fibrinogen level is >2.0 g/L (this is higher than the general haematology threshold of >1.0 g/L) because obstetric patients have physiologically elevated fibrinogen in pregnancy (normal term fibrinogen 4-6 g/L). A fibrinogen of 1.0-1.5 g/L, which might be acceptable in non-pregnant patients, represents significant depletion in an obstetric patient and predicts ongoing coagulopathy.
Obstetric DIC fibrinogen target: >2 g/L (not the non-obstetric >1 g/L), because baseline fibrinogen in pregnancy is 4-6 g/L. Use cryoprecipitate (10-pool bag = 5-6 g fibrinogen) to achieve this target rapidly.
In obstetric DIC, target fibrinogen is >2.0 g/L — higher than the general threshold of >1.0 g/L — because baseline fibrinogen in late pregnancy is 4-6 g/L (elevated by oestrogen). A fibrinogen of 1.5 g/L may appear 'normal' but represents severe depletion in a pregnant woman.
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A 28-year-old patient with MCMA (monochorionic monoamniotic) twins is being counselled about delivery timing. At what gestational age is delivery typically planned for uncomplicated MCMA twins?
Correct. MCMA twins are the highest-risk multiple pregnancy because the shared amniotic sac allows cord entanglement (present in virtually all MCMA pregnancies from early gestation) and acute cord accidents. Delivery is planned at 32-34 weeks by elective caesarean section. MCDA twins are delivered at 36-37 weeks; DCDA uncomplicated at 37-38 weeks.
Delivery timing by chorionicity/amnionicity: MCMA = 32-34 weeks (cord entanglement risk); MCDA = 36-37 weeks (TTTS/TRAP risk); DCDA uncomplicated = 37-38 weeks. Chorionicity determines surveillance and delivery.
MCMA twins require earliest delivery (32-34 weeks) due to cord entanglement risk in the shared amniotic sac. MCDA delivery: 36-37 weeks. Uncomplicated DCDA: 37-38 weeks. 28-30 weeks is earlier than necessary given modern NICU outcomes.
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