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cardio.dvt.pregnancy.v1

DVT during pregnancy / postpartum

cardiologyacuteadultpregnancyacuteinpatienttransitionoutpatient
Start encounter →Print handoutPRODUCTION

Phase E variant of cardio.dvt.core.v1 — DVT during pregnancy / postpartum sub-population. Pregnancy is hypercoagulable state + mechanical compression (gravid uterus → left iliac vein) → >80% left-sided iliofemoral DVT predominance. Treatment paradigm fundamentally different: LMWH (enoxaparin 1 mg/kg SC BID weight-based) throughout pregnancy + 6 wk postpartum minimum; DOAC and warfarin CONTRAINDICATED antepartum (warfarin embryopathy 6-12 wk + CNS bleeding any trimester; DOAC crosses placenta with limited safety data). Manifest pointer reuses cardio.dvt.core.v1 manifest. Design-brief pointer reuses parent. Delivery planning: hold LMWH ≥24 h before scheduled delivery / induction (12 h prophylactic dose); restart 6-12 h post-delivery if hemostasis adequate (12-24 h post C-section per RCOG Green-top 37a). Postpartum: continue LMWH × 6 wk minimum; warfarin compatible with breastfeeding (LactMed); DOAC NOT compatible with breastfeeding. 5 setting playbooks (ED, inpatient floor, ICU for phlegmasia / massive PE, transition for peripartum LMWH coordination + 6-wk postpartum plan, outpatient long-term + future pregnancy planning). 6 severity triggers (peripartum bleeding on AC, postpartum thrombosis recurrence, DOAC misuse / pregnancy exposure, phlegmasia in pregnancy, IVC filter retrieval timing, concurrent PE in pregnancy). 4 band-mapped calculators (wells_dvt with LEFt-rule modification, has_bled 0-1 / 2 / ≥3, ckd_epi_2021 NOT validated in pregnancy noted, caprini for surgical-context VTE risk). Status INTEGRATED. Authored 2026-05-15 by shard-06-cardio-acute as Phase E wave 9 sub-population variant.

Entry points (4)

  • symptom
    Pregnant patient with left leg swelling, calf pain, or whole-leg edema (>80% of pregnancy DVT is left-sided due to right common iliac artery compression of left common iliac vein)
    left_leg_swelling_in_pregnancy
  • imaging
    Compression US confirms iliofemoral DVT in pregnant patient — initiate LMWH immediately; MRV if pelvic vein extension suspected
    us_iliofemoral_dvt_pregnancy
  • history
    Postpartum (within 6 weeks) calf pain, swelling, or PE symptoms — postpartum is the highest-risk window for VTE (~5× pregnancy risk)
    postpartum_calf_pain_swelling
  • symptom
    Pregnant patient with DVT plus dyspnea, pleuritic chest pain, syncope, or hypoxemia → image for concurrent PE (CT-PA radiation acceptable; <0.1 mGy fetal dose)
    pregnancy_dvt_with_dyspnea

Required inputs (12)

  • gestational_agerequired
    demographic • used at CONTEXT
    Drives risk-benefit (warfarin embryopathy 6-12 wk; delivery planning >34 wk; postpartum window 0-6 wk highest VTE risk)
  • parityrequired
    demographic • used at CONTEXT
    Multiparity adds VTE risk; informs counseling for future pregnancies
  • pregnancyrequired
    history • used at FRAME
    Confirms pregnancy status — drives entire treatment paradigm (LMWH only, NO DOAC, NO warfarin antepartum)
  • breastfeeding_intentrequired
    history • used at TREATMENT
    Postpartum AC choice depends — LMWH and warfarin compatible with breastfeeding; DOAC NOT recommended (LactMed)
  • delivery_plan
    history • used at TREATMENT
    Scheduled C-section vs spontaneous labor changes LMWH hold strategy; neuraxial anesthesia requires ≥24 h LMWH hold
  • compression_usrequired
    imaging • used at INITIAL_WORKUP
    First-line diagnostic imaging in pregnancy DVT (ASH 2018; RCOG 37a) — femoral + popliteal; pelvic vein limited but informs MRV need
  • mrv_iliac_pelvic
    imaging • used at BRANCHING_WORKUP
    MRV (without gadolinium) for suspected iliac / pelvic vein DVT not visualized on compression US; gadolinium AVOIDED in pregnancy (Cat C; crosses placenta)
  • creatininerequired
    lab • used at TREATMENT
    Pregnancy increases GFR by 50%; LMWH dosing weight-based but anti-Xa monitoring useful at extremes; CKD-EPI not validated in pregnancy
  • cbcrequired
    lab • used at INITIAL_WORKUP
    Baseline platelets + Hgb for HIT screen + bleeding risk; pregnancy anemia common (dilutional) requires baseline
  • liver_function
    lab • used at INITIAL_WORKUP
    LFT baseline before LMWH (rare hepatotoxicity); pregnancy-related liver disease (HELLP, AFLP) excluded
  • prior_vterequired
    history • used at CONTEXT
    Prior VTE = strong indication for prophylactic or therapeutic LMWH throughout pregnancy + postpartum (RCOG 37a)
  • thrombophilia_known
    history • used at CONTEXT
    Antithrombin deficiency, APS, homozygous Factor V Leiden modify dose intensity (RCOG 37a)

12-phase flow (11)

  1. 1FRAME
    DVT in pregnancy = LMWH-only paradigm (NO DOAC, NO warfarin antepartum); >80% left-sided iliofemoral due to mechanical compression; gravid uterus + hypercoagulable state; postpartum window 0-6 wk is highest VTE risk; coordinate with MFM + OB throughout
    inputs: pregnancy, gestational_age
    advance: pregnancy confirmed and gestational age established
  2. 2ENTRY
    Recognize left leg swelling / pain in pregnant patient — pretest probability higher than non-pregnant given anatomic + hormonal predisposition; Wells score validated less in pregnancy (modified scores like LEFt rule emerging)
    inputs: gestational_age, parity
    advance: pretest probability assigned and laterality noted
  3. 3CONTEXT
    Prior VTE, thrombophilia (especially APS, antithrombin deficiency), parity, mode of conception (ART increases risk), planned delivery mode + timing, breastfeeding intent
    inputs: prior_vte, breastfeeding_intent
    advance: context complete
  4. 4RED_FLAGS
    Phlegmasia cerulea dolens (rare but limb + pregnancy emergency); concurrent PE (CT-PA fetal dose <0.1 mGy acceptable; V/Q lower fetal dose alternative); peripartum bleeding on AC; HELLP / PE / abruption mimics with leg pain
    actions: acute_limb_ischemia, pe_full
    advance: limb-threatening + concurrent-PE + obstetric mimics screened
  5. 5INITIAL_WORKUP
    Compression US (femoral + popliteal) first-line; CBC + BMP + LFT + INR/PTT baseline; D-dimer interpreted with pregnancy-adjusted cutoffs (DiPEP study); Wells score modified
    inputs: compression_us, cbc, creatinine
    actions: panel.cardiac, panel.renal
    advance: DVT confirmed or ruled out
  6. 6BRANCHING_WORKUP
    MRV (no gadolinium) for suspected iliac / pelvic DVT not visualized on US; thrombophilia testing per ASH 2023 indications (recurrent loss + VTE history); cancer screening NOT routine in pregnancy
    inputs: mrv_iliac_pelvic
    advance: extended imaging plan documented
  7. 7RISK_STRATIFICATION
    Severity for AC dose (therapeutic 1 mg/kg BID standard; intermediate dose 1 mg/kg daily for prophylaxis after acute phase or in some recurrent cases); HAS-BLED + obstetric bleed risk (placenta previa, accreta, low platelets) drives delivery LMWH hold strategy
    inputs: prior_vte
    actions: calc.has_bled
    advance: dose intensity + delivery-hold plan documented
  8. 8TREATMENT
    Therapeutic LMWH (enoxaparin 1 mg/kg SC BID weight-based) throughout pregnancy + 6 wk postpartum minimum; UFH continuous infusion alternative if delivery imminent or severe renal impairment; DOAC and warfarin CONTRAINDICATED antepartum; postpartum can transition to warfarin (compatible with breastfeeding) — DOAC NOT recommended due to limited breastfeeding data
    inputs: creatinine, breastfeeding_intent, delivery_plan
    advance: LMWH dose + delivery plan + postpartum AC plan documented
  9. 9DISPOSITION
    Outpatient LMWH for hemodynamically stable iliofemoral DVT with reliable patient + MFM access; admit for phlegmasia, concurrent PE, peripartum delivery, social factors
    advance: disposition + MFM follow-up arranged
  10. 10MONITORING
    Anti-Xa level (peak 0.6-1.0 IU/mL for BID dosing) at 4 h post-dose at extremes of weight or renal impairment; CBC weekly first 2 wk for HIT screen; weight-based dose adjustment q4 wk through pregnancy as weight increases; coordinate delivery LMWH hold ≥24 h before scheduled / 12 h prophylactic dose
    actions: panel.cardiac
    advance: monitoring schedule + delivery coordination plan documented
  11. 11FOLLOWUP
    Postpartum 6 wk LMWH minimum; transition to warfarin or continue LMWH per patient preference + breastfeeding (DOAC NOT recommended in lactation); contraception counseling (avoid combined OCP — OCP increases VTE risk 3-6×; progestin-only or non-hormonal preferred); future pregnancy thromboprophylaxis plan documented
    advance: 6-wk postpartum AC + contraception + future pregnancy plan finalized