12-phase flow (12)

1. 1FRAME
   Breech presentation at term — fetal presentation with buttocks/feet at cervix at ≥ 37 wk; affects ~ 3-4% of term pregnancies. Types: FRANK (hips flexed, knees extended, feet near head — most common ~ 65%), COMPLETE (hips + knees flexed, "cannonball"), INCOMPLETE-FOOTLING (one or both feet below buttocks). Mode-of-delivery decision framed by Hannah 2000 Term Breech Trial Lancet (PMID 11052579) — planned cesarean superior for perinatal mortality/serious morbidity (1.6% vs 5.0%; RR 0.33) — vs Goffinet 2006 PREMODA AJOG (PMID 16580289) showing safe planned vaginal breech in select units with strict criteria. ACOG CO 745 (PMID 30045211) offers ECV as alternative to planned cesarean; trial of vaginal breech may be reasonable under hospital-specific protocol with detailed informed consent.
   inputs: gestational_age_weeks_exact
   advance: GA + presentation type documented; mode-of-delivery framework set
2. 2ENTRY
   Recognise via routine antenatal ultrasound at 36-37 wk, palpation on Leopold maneuvers (head ballottable at fundus + buttocks at pelvis + fetal heart sounds above umbilicus), or presentation in labor. Differential: transverse/oblique lie (also non-vertex, mandates cesarean); compound presentation; vertex with deflexion (occiput posterior, brow, face); persistent breech vs late spontaneous version. Cord prolapse after rupture of membranes is EMERGENCY — knee-chest position + manual elevation of presenting part + emergent cesarean.
   inputs: gestational_age_weeks_exact
   advance: Breech confirmed by US; type characterised; cord prolapse ruled out
3. 3CONTEXT
   Capture parity (multiparity increases ECV success), prior cesarean (classical absolute contraindication to TOLAC; relative to ECV; low transverse less restrictive), placenta previa / low-lying placenta (absolute contraindication to ECV and to vaginal delivery), estimated fetal weight (EFW 2500-4000 g acceptable for vaginal breech per ACOG CO 745), amniotic fluid index (oligohydramnios raises cord prolapse risk + reduces ECV success; polyhydramnios facilitates ECV), Rh status (Rho(D) IG after ECV if Rh-negative), fetal anomalies / growth restriction (may contraindicate ECV / vaginal breech), and maternal preference (mode-of-delivery is a shared decision).
   inputs: parity_and_prior_delivery_modes, prior_classical_cesarean_or_uterine_surgery, placenta_previa_or_low_lying_placenta, estimated_fetal_weight, amniotic_fluid_index, maternal_rh_status, fetal_anomalies_or_growth_restriction
   advance: ECV candidacy + vaginal breech candidacy + planned cesarean defaulting documented
4. 4RED_FLAGS
   Cord prolapse on rupture of membranes → IMMEDIATE knee-chest position + manual elevation of presenting part + emergent cesarean (cesarean within 30 min standard; immediate transport to OR). Non-reassuring FHR (Category III) → emergent cesarean (regardless of mode-of-delivery plan). Placenta previa diagnosis → planned cesarean (ECV CONTRAINDICATED). Prior classical cesarean → planned cesarean (ECV relative contraindication, vaginal delivery absolutely contraindicated). Severe pre-eclampsia → expedite delivery per ob.pre-eclampsia.core.v1.
   inputs: fetal_heart_rate_baseline_and_pattern, placenta_previa_or_low_lying_placenta, prior_classical_cesarean_or_uterine_surgery, maternal_bp
   advance: Red-flag pathway activated: cord prolapse → emergent cesarean; non-reassuring FHR → emergent cesarean; placenta previa / prior classical → planned cesarean
5. 5INITIAL_WORKUP
   Confirmatory transabdominal ultrasound (presentation type — frank / complete / footling — and exclude transverse/oblique; EFW; placental location; AFI; biophysical profile if growth concern; cervical length). Baseline CBC + type and screen. Continuous EFM at presentation in labor. Document ECV candidacy assessment + vaginal breech criteria evaluation (ACOG CO 745 + RCOG GTG 20b).
   inputs: transabdominal_ultrasound_at_term, maternal_cbc_and_type_screen, fetal_heart_rate_baseline_and_pattern
   actions: panel.cbc
   advance: US confirms presentation + EFW + placental location + AFI; baseline labs + type and screen; FHR reassuring
6. 6BRANCHING_WORKUP
   If anomaly suspected → detailed anomaly ultrasound. If TOLAC under consideration with prior low transverse cesarean → assess uterine scar (no routine US needed); informed consent for TOLAC. If trial of vaginal breech under consideration → meet ACOG CO 745 criteria + hospital protocol; ensure experienced provider availability; counsel risks per Term Breech Trial.
   actions: workup.preeclampsia
   advance: Branching workups completed as indicated; mode-of-delivery decision finalised
7. 7DIFFERENTIAL
   Transverse / oblique lie (also non-vertex; mandates cesarean; cannot ECV after 39 wk reliably); compound presentation (hand or foot alongside vertex; intrapartum management); vertex with deflexion (occiput posterior, brow, face — different intrapartum management); persistent breech vs late spontaneous version (~ 8% of term breech turn spontaneously between 36 and 40 wk, more in multiparas).
   advance: Differential narrowed; breech vs transverse vs vertex-deflexion confirmed
8. 8RISK_STRATIFICATION
   ECV CANDIDACY: no contraindications (placenta previa, recent vaginal bleeding, non-reassuring FHR, hyperextended fetal head, severe FGR, multifetal gestation — relative, prior classical cesarean — relative) → offer ECV at ≥ 37 wk; success rate ~ 50-60% (higher in multiparas, polyhydramnios, posterior placenta, normal BMI). VAGINAL BREECH CANDIDACY per ACOG CO 745: hospital-specific protocol; frank or complete breech (not footling); EFW 2500-4000 g; experienced provider; no fetal anomaly; pelvic adequacy; favorable cervical exam; detailed informed consent including Term Breech Trial findings. PLANNED CESAREAN: ECV failed/declined/contraindicated + not vaginal breech candidate.
   inputs: estimated_fetal_weight, amniotic_fluid_index, placenta_previa_or_low_lying_placenta, fetal_anomalies_or_growth_restriction, parity_and_prior_delivery_modes
   advance: ECV vs vaginal breech vs planned cesarean decision documented with rationale + informed consent
9. 9TREATMENT
   EXTERNAL CEPHALIC VERSION (ECV) at ≥ 37 wk per ACOG CO 745 (PMID 30045211); performed at L&D facility with OR available; continuous EFM before/during/after; success ~ 50-60%. TOCOLYTIC TO FACILITATE ECV: terbutaline 0.25 mg SC ×1 (RxCUI 10368; PregCat former B; LactMed compatible with caution) 15 min before ECV; nifedipine 20 mg PO alternative. RHO(D) IMMUNE GLOBULIN 300 µg IM ×1 within 72 h if Rh-negative (small fetomaternal hemorrhage risk from ECV). PLANNED CESAREAN if ECV fails or contraindicated (default per Term Breech Trial Hannah 2000 Lancet PMID 11052579); schedule at 39+0 wk if elective. SELECTIVE TRIAL OF VAGINAL BREECH per ACOG CO 745 + RCOG GTG 20b strict criteria + hospital protocol + experienced provider + detailed informed consent. CORD PROLAPSE: emergent cesarean with knee-chest position + manual elevation of presenting part until OR.
   inputs: gestational_age_weeks_exact, patient_preference_and_informed_consent
   advance: ECV performed (if candidate) or planned cesarean scheduled or trial of labor underway; Rho(D) IG given if applicable
10. 10DISPOSITION
    OUTPATIENT ECV scheduled at L&D procedure room with OR backup. INPATIENT for delivery admission (cesarean or trial of vaginal breech). ED for cord prolapse on rupture of membranes (emergent cesarean transport) or active labor with non-vertex presentation requiring rapid OR mobilization.
    inputs: gestational_age_weeks_exact
    advance: Level of care set; ECV scheduling or delivery admission coordinated
11. 11MONITORING
    PRE-ECV: NST reassuring; baseline US; informed consent; type and screen. DURING ECV: continuous EFM; transient FHR decelerations common (typically self-resolving); stop if bradycardia / persistent abnormal FHR. POST-ECV: continuous EFM for 30 min then NST reassuring; assess for vaginal bleeding / abdominal pain (placental abruption risk small); discharge with return precautions. INTRAPARTUM IF TRIAL OF VAGINAL BREECH: continuous EFM; experienced provider at bedside throughout; second-stage no longer than 1 h; readiness for emergent cesarean. POST-CESAREAN: routine post-op care.
    inputs: fetal_heart_rate_baseline_and_pattern
    advance: Successful version OR ECV unsuccessful / contraindicated → delivery planning; intrapartum monitoring continuous if trial of labor
12. 12FOLLOWUP
    Postpartum debrief if cesarean for breech — counsel TOLAC eligibility in subsequent pregnancies (~ 10% recurrence of breech; most subsequent pregnancies vertex). Breastfeeding support per standard postpartum care. Routine 6-wk visit. Genetic counseling if anomalies found. If ECV-failure cesarean — counsel ECV may be re-offered in subsequent pregnancy if breech recurs.
    advance: Postpartum debrief delivered; TOLAC counseling complete; routine postpartum follow-up arranged