Eduovisual
Pregnancy, Childbirth & Puerperium
VTE in pregnancy: prevention and treatment
— Pregnancy increases VTE risk 4–5 fold; postpartum period (especially first 6 weeks) carries the highest absolute risk (~20-fold baseline)
— VTE remains a leading cause of maternal mortality in the US, accounting for ~9% of pregnancy-related deaths
— ~80% of pregnancy-associated VTE is DVT; ~20% is PE; DVT is left-leg predominant (~85%) due to compression of left iliac vein by right iliac artery and gravid uterus (May-Thurner physiology)
— Iliofemoral location is disproportionately common compared to nonpregnant patients
— Hypercoagulability: rising factors I, II, VII, VIII, X, IX; falling protein S; acquired activated protein C resistance
— Venous stasis: progesterone-mediated venodilation + uterine compression of IVC/iliac veins
— Endothelial injury: delivery, especially cesarean
— Unilateral leg swelling, calf pain, or left-sided lower extremity symptoms in any trimester or up to 12 weeks postpartum
— Pleuritic chest pain, dyspnea, tachycardia disproportionate to gestation, syncope, unexplained hypoxia
— Do not anchor on "pregnancy-related dyspnea" — physiologic dyspnea is exertional and gradual; sudden or pleuritic dyspnea warrants workup
— Prior VTE, known thrombophilia, cesarean (especially emergent), preeclampsia, obesity (BMI ≥30), age >35, multiparity, immobilization, ART, postpartum hemorrhage, infection
Board pearl: Wells score and PERC are not validated in pregnancy; clinical suspicion alone should trigger objective imaging. The YEARS algorithm adapted for pregnancy (with D-dimer thresholds) is the only well-studied rule but is not yet standard on US boards — when in doubt, image.
— Unilateral leg pain and swelling, often described as cramping or heaviness; calf tenderness
— Left leg involvement in ~85% — high-yield exam clue
— Iliofemoral DVT may present with whole-leg swelling, groin/flank/lower abdominal pain, or buttock pain rather than calf complaints
— Symptoms often blamed on "normal pregnancy edema" — asymmetry is the key
— Postpartum DVT may emerge 2–6 weeks after delivery, often after discharge
— Acute dyspnea, pleuritic chest pain, tachycardia, hemoptysis, presyncope/syncope
— May present as isolated unexplained tachycardia or persistent hypoxia
— Massive PE: hypotension, RV strain, cardiac arrest (PEA most common rhythm)
— Prior VTE (and whether estrogen-provoked, pregnancy-provoked, or unprovoked) — drives both prophylaxis decisions and treatment duration
— Family history of VTE in first-degree relative <50 yo
— Known thrombophilia: factor V Leiden, prothrombin G20210A, antithrombin deficiency, protein C/S deficiency, antiphospholipid syndrome (APS)
— Recurrent pregnancy loss, IUGR, severe preeclampsia, stillbirth → screen for APS
— Mode of delivery (planned/prior cesarean), bedrest, hyperemesis with dehydration, OHSS in this pregnancy
— Smoking, BMI, age, parity ≥3, multiple gestation, ART conception
— Postpartum hemorrhage, transfusion, infection (endometritis), prolonged labor, instrumented or cesarean delivery
— Time since delivery (peak risk first 3 weeks, elevated through 12 weeks postpartum)
Key distinction: "Provoked by prior pregnancy or estrogen" vs "unprovoked" prior VTE matters more than the absolute number of prior events — it determines whether antepartum prophylactic anticoagulation is required this pregnancy (ACOG/ACCP guidance).
— Measure calf circumference 10 cm below tibial tuberosity bilaterally; >2 cm difference is significant
— Palpate for cords, warmth, tenderness along deep venous distribution
— Homans sign is insensitive and nonspecific — do not rely on it
— Assess for phlegmasia cerulea dolens (massive iliofemoral DVT): cyanotic, swollen, painful leg — surgical/IR emergency
— Examine groin and lower abdomen for iliofemoral tenderness
— Vitals: tachycardia (HR >100), tachypnea (RR >20), SpO₂ <95% on room air are red flags (recall baseline pregnancy HR is already 10–15 bpm higher)
— Auscultate for clear lungs (PE classically), pleural rub, or focal crackles
— Loud P2, right parasternal heave, elevated JVP suggest RV strain
— Hypotension or shock → massive PE until proven otherwise
— Stable PE: normotensive, SpO₂ maintained — anticoagulation alone
— Submassive (intermediate-risk): RV dysfunction on echo or elevated troponin/BNP, but normotensive
— Massive: SBP <90 mmHg or vasopressor requirement, or cardiac arrest — consider systemic thrombolysis despite pregnancy (pregnancy is a relative, not absolute, contraindication)
— Document fetal heart tones; continuous fetal monitoring if viable (≥23–24 weeks) and mother is unstable
— Left lateral decubitus positioning to relieve IVC compression during evaluation
Step 3 management: Hemodynamically unstable PE in pregnancy → maternal stabilization first (ABC, IV access, oxygen, left lateral tilt, fluids cautiously), then systemic tPA or catheter-directed therapy if available. Do not delay thrombolysis in arrest — maternal survival is fetal survival.
— D-dimer rises physiologically each trimester; standard cutoff (500 ng/mL) loses specificity
— A negative high-sensitivity D-dimer still has reasonable negative predictive value, especially in the first trimester, but pregnancy-adjusted cutoffs are not standardized on US boards
— Do not use D-dimer alone to rule out VTE in pregnancy on Step 3 — pair with imaging
— CBC (baseline platelets before heparin), creatinine (LMWH dosing), LFTs, PT/INR, aPTT (baseline)
— Type and screen if peripartum or unstable
— Troponin and BNP if PE suspected (risk stratification)
— Antiphospholipid panel (lupus anticoagulant, anti-cardiolipin, anti–β2 glycoprotein I) if unprovoked or recurrent loss history — draw before anticoagulation when feasible
— Sinus tachycardia is most common finding
— Classic S1Q3T3, RBBB, or T-wave inversions V1–V4 suggest RV strain
— Rule out ACS mimics
— Often normal in PE; shields used to minimize fetal exposure
— Useful to evaluate alternative diagnoses (pneumonia, pneumothorax) and to guide choice between V/Q and CTPA
— First-line for suspected DVT in pregnancy; no radiation
— In suspected PE with leg symptoms, start with bilateral CUS — a positive CUS confirms VTE and obviates chest imaging (treat both DVT and PE the same way)
— If CUS negative but high suspicion for iliac DVT → MR venography (no contrast needed for thrombus visualization)
Board pearl: The diagnostic shortcut on Step 3: suspected PE + leg symptoms → bilateral leg CUS first. A positive study lets you skip CTPA/V-Q entirely, sparing fetal and maternal breast radiation.
— Two options: CT pulmonary angiogram (CTPA) vs V/Q scan
— Both deliver acceptable fetal radiation doses (<5 mSv threshold for fetal harm); choice depends on CXR and institutional factors
— Preferred when CXR is normal — high diagnostic yield in pregnancy because lungs are typically clear
— Slightly higher fetal radiation dose than CTPA but lower maternal breast radiation (relevant given lifetime breast cancer risk and lactating tissue)
— Often performed as perfusion-only scan in pregnancy to reduce dose
— Preferred when CXR is abnormal, when V/Q is unavailable, or when alternative diagnoses (dissection, pneumonia) are likely
— Lower fetal dose but higher maternal breast radiation (~10–70 mGy) — counsel patient
— Iodinated contrast is category B; brief neonatal TSH check recommended if used near term
— No radiation, but gadolinium avoided in pregnancy when possible (crosses placenta); non-contrast techniques limited; not first-line
— Bedside transthoracic echo if hemodynamically unstable: RV dilation, McConnell sign, septal flattening, TR jet → supports massive/submassive PE
— Helps guide thrombolysis decision when CT cannot be obtained
— Suspected isolated iliac vein thrombosis (whole-leg swelling, buttock/back pain, negative femoropopliteal CUS) → MR venography or contrast venography
Key distinction: Normal CXR → V/Q first; abnormal CXR → CTPA first. Both are acceptable in pregnancy; the dogma "never CT a pregnant patient" is wrong. Missed PE kills the mother and fetus — diagnostic certainty trumps radiation anxiety.
Board pearl: Informed consent for chest imaging should document the risk of missed PE > risk of imaging-related fetal harm.
— (1) Who needs prophylaxis (no current VTE, but at risk)
— (2) How to treat established VTE
— Prior VTE, estrogen- or pregnancy-provoked → prophylactic LMWH antepartum + 6 weeks postpartum
— Prior unprovoked VTE → prophylactic or intermediate-dose LMWH antepartum + 6 weeks postpartum
— Prior VTE on long-term anticoagulation (e.g., recurrent, APS) → therapeutic-dose LMWH throughout pregnancy and 6 weeks postpartum
— High-risk thrombophilia (antithrombin deficiency, homozygous FVL or PGM, compound heterozygous, APS) + family history → prophylaxis antepartum and postpartum
— Low-risk thrombophilia + no personal/family history → surveillance only antepartum, postpartum prophylaxis if additional risk factors
— No prior VTE, no thrombophilia, cesarean delivery → mechanical prophylaxis intraoperatively; pharmacologic prophylaxis postpartum if additional risk factors (BMI ≥40, prolonged surgery, sepsis, preeclampsia, age >35, etc.)
— Submassive/massive PE → consider thrombolysis, IR consult, ICU
— Stable DVT/PE → therapeutic LMWH outpatient or short admission
— Iliofemoral DVT with phlegmasia → catheter-directed thrombolysis or thrombectomy
— LMWH = first-line (does not cross placenta, predictable kinetics)
— UFH reserved for renal failure, peripartum (shorter half-life), or hemodynamic instability
— Warfarin contraindicated (teratogenic 6–12 weeks; fetal/CNS bleeding)
— DOACs contraindicated (insufficient safety data, cross placenta)
Step 3 management: When a stem gives "prior unprovoked DVT, now 8 weeks pregnant," the answer is start prophylactic LMWH now and continue through 6 weeks postpartum — do not wait until later in pregnancy.
— Prophylactic: enoxaparin 40 mg SC daily (or dalteparin 5000 units daily)
— Intermediate: enoxaparin 40 mg SC q12h or weight-adjusted (0.5 mg/kg q12h)
— Therapeutic: enoxaparin 1 mg/kg SC q12h (preferred in pregnancy over once-daily 1.5 mg/kg dosing due to altered pharmacokinetics — increased renal clearance and volume of distribution)
— Dose based on early-pregnancy or current weight; some increase dose with gestational weight gain
— Anti-Xa monitoring: not routine; consider in extremes of body weight (<50 kg, >90 kg), renal impairment, recurrent VTE on therapy; target peak anti-Xa 0.6–1.0 IU/mL (q12h dosing) 4 hours post-dose
— Used when rapid reversal anticipated (near delivery), severe renal impairment (CrCl <30), or hemodynamic instability requiring titration
— IV bolus 80 units/kg then 18 units/kg/hr; titrate to aPTT 1.5–2.5× control or anti-Xa 0.3–0.7
— SC UFH 5000 units q12h is inadequate prophylaxis later in pregnancy — dose escalation needed
— Warfarin: teratogenic (nasal hypoplasia, stippled epiphyses, CNS bleeding); safe postpartum and during breastfeeding
— DOACs (apixaban, rivaroxaban, dabigatran, edoxaban): avoided in pregnancy and lactation
— Fondaparinux: alternative if HIT develops; limited safety data but used when LMWH/UFH not options
— Acute VTE in pregnancy: therapeutic anticoagulation throughout remainder of pregnancy + at least 6 weeks postpartum, for a minimum total duration of 3 months
Board pearl: Switch to twice-daily dosing in pregnancy because increased GFR and Vd shorten LMWH half-life — once-daily therapeutic dosing risks subtherapeutic troughs.
CCS pearl: Order CBC, creatinine, PT/aPTT before starting, and platelets at day 5–10 to screen for HIT (though HIT is rare with LMWH).
— Therapeutic LMWH: hold for 24 hours before planned induction/cesarean or neuraxial anesthesia
— Prophylactic LMWH: hold for 12 hours before neuraxial anesthesia
— UFH SC prophylactic dose: hold 4–6 hours and check aPTT before neuraxial; therapeutic IV UFH hold ≥4–6 hours with normal aPTT
— Spontaneous labor on LMWH: avoid neuraxial; general anesthesia if cesarean needed urgently
— At 36–37 weeks, transition from LMWH to SC or IV UFH in high-risk patients to allow shorter washout, OR plan scheduled induction with timed last LMWH dose 24 hours prior
— Resume anticoagulation 4–6 hours after vaginal delivery, 6–12 hours after cesarean, assuming hemostasis; epidural catheter must be removed before restarting therapeutic doses (≥4 hours after catheter removal)
— Reserved for acute proximal DVT or PE within 2–4 weeks of delivery with contraindication to anticoagulation (active bleeding, planned imminent surgery)
— Use retrievable filters; remove postpartum once anticoagulation safe
— Not for routine VTE in pregnancy
— Systemic tPA (alteplase 100 mg over 2 hr or 0.6 mg/kg bolus in arrest) — pregnancy is relative contraindication, but maternal hemodynamic collapse outweighs risk
— Catheter-directed thrombolysis uses lower doses, preferred when stable enough for IR
— Surgical embolectomy if thrombolysis contraindicated
— Catheter-directed thrombolysis or mechanical thrombectomy by IR; full anticoagulation thereafter
CCS pearl: On exam day, the sequence near term is: scheduled induction → last therapeutic LMWH dose 24 h prior → confirm normal coags → neuraxial OK → deliver → restart anticoagulation 6–12 h postpartum → bridge to warfarin or continue LMWH for ≥6 weeks.
— LMWH is renally cleared; accumulates in renal dysfunction → bleeding risk
— CrCl <30 mL/min: use UFH preferentially, OR reduce enoxaparin dose (e.g., 1 mg/kg daily for therapeutic, 30 mg daily for prophylaxis) with anti-Xa monitoring
— Dialysis-dependent pregnancy is rare but high-risk — coordinate with nephrology; UFH typically used
— Pregnancy normally increases GFR by 50%; "normal" creatinine in pregnancy is lower (~0.5–0.7 mg/dL) — a creatinine of 0.9 may signal real dysfunction
— Pregnancy-specific liver disease (HELLP, AFLP, intrahepatic cholestasis) complicates anticoagulation due to coagulopathy and thrombocytopenia
— In HELLP with platelets <50,000 or active bleeding: hold anticoagulation, use mechanical prophylaxis (sequential compression devices)
— UFH preferred for rapid reversibility; protamine fully reverses UFH and partially reverses LMWH
— Avoid warfarin postpartum until LFTs and coags normalize
— Higher VTE risk; postpartum prophylaxis indicated even after vaginal delivery if additional risk factors
— Therapeutic LMWH dosing: actual body weight, capped or anti-Xa monitored in extreme obesity
— Consider intermediate-dose prophylaxis (enoxaparin 40 mg q12h) antepartum
— Rare with LMWH; if develops, switch to fondaparinux (off-label but used) or argatroban (limited pregnancy data)
— DOACs and warfarin contraindicated in pregnancy even for HIT
— Lower threshold for postpartum prophylaxis
Board pearl: Pregnant patient with CrCl <30 and need for anticoagulation → switch from LMWH to IV UFH with aPTT monitoring; do not just lower the LMWH dose unless anti-Xa monitoring available.
— High-risk: antithrombin deficiency, homozygous factor V Leiden, homozygous prothrombin G20210A, compound heterozygous FVL/PGM
— Low-risk: heterozygous FVL, heterozygous PGM, protein C or S deficiency
— Low-risk thrombophilia, no prior VTE, no family history → surveillance antepartum; consider postpartum prophylaxis with additional risk factors
— Low-risk thrombophilia + family history of VTE → antepartum surveillance; postpartum prophylaxis ×6 weeks
— High-risk thrombophilia, no prior VTE → prophylactic or intermediate LMWH antepartum + postpartum ×6 weeks
— Any thrombophilia + prior VTE → therapeutic or intermediate LMWH antepartum + postpartum ×6 weeks
— Diagnosis: ≥1 clinical criterion (vascular thrombosis OR pregnancy morbidity — ≥3 consecutive losses <10 wk, ≥1 fetal loss ≥10 wk, or severe preeclampsia/placental insufficiency <34 wk) PLUS persistently positive aPL antibodies (×2, 12 weeks apart): lupus anticoagulant, anti-cardiolipin IgG/IgM, anti–β2GPI IgG/IgM
— APS with prior thrombosis: therapeutic LMWH + low-dose aspirin throughout pregnancy + postpartum (often lifelong warfarin postpartum)
— APS with prior pregnancy morbidity only (no thrombosis): prophylactic LMWH + low-dose aspirin (81 mg) starting in first trimester through 6 weeks postpartum
— aPL positive but no clinical criteria: low-dose aspirin alone is reasonable
— Neonates of mothers with APS: monitor for neonatal thrombosis (rare); maternal warfarin postpartum is compatible with breastfeeding
Key distinction: Aspirin alone is never sufficient for APS with prior thrombosis — must add therapeutic LMWH. APS with pregnancy morbidity only gets prophylactic LMWH + aspirin, not therapeutic dosing.
— Death: PE is among top 3 causes of maternal mortality in US
— Recurrent VTE during same pregnancy or postpartum
— Post-thrombotic syndrome (PTS): chronic leg swelling, pain, hyperpigmentation, ulceration — affects up to 40% after iliofemoral DVT; mitigated by adequate anticoagulation and graduated compression stockings
— Chronic thromboembolic pulmonary hypertension (CTEPH): long-term sequel of PE; dyspnea persisting >3 months post-PE → V/Q scan and PH workup
— Bleeding: peripartum hemorrhage, wound hematoma, intraspinal hematoma with neuraxial anesthesia (catastrophic — paralysis)
— HIT (rare with LMWH, ~0.1%); UFH risk ~1–3%
— Heparin-induced osteoporosis with prolonged UFH (>1 month); less with LMWH
— Injection site reactions, skin necrosis (rare; consider HIT)
— Allergy / cross-reactivity between LMWH preparations
— Antiphospholipid syndrome → recurrent miscarriage, IUGR, severe preeclampsia, placental abruption, stillbirth
— Inherited thrombophilias inconsistently linked to placental insufficiency outcomes
— Maternal arrest from massive PE → hypoxic-ischemic injury, fetal demise; perimortem cesarean if maternal arrest and gestation ≥23 weeks and no ROSC within 4 minutes
— Septic pelvic thrombophlebitis: persistent fever postpartum despite antibiotics; pelvic CT/MR shows ovarian or pelvic vein thrombosis; treat with anticoagulation + broad-spectrum antibiotics
— Endometritis as inflammatory trigger for VTE
Step 3 management: Persistent postpartum fever unresponsive to 48–72 hours of broad-spectrum antibiotics for presumed endometritis → think septic pelvic thrombophlebitis; add therapeutic heparin empirically for 7–10 days plus continued antibiotics.
— Hemodynamically unstable PE (SBP <90, vasopressors, lactate elevation)
— Submassive PE with RV dysfunction, rising troponin, or worsening hypoxia
— Massive iliofemoral DVT with phlegmasia
— Maternal arrest or post-arrest care
— Active major bleeding on anticoagulation
— MFM (maternal-fetal medicine): all pregnant patients with acute VTE or therapeutic anticoagulation
— Hematology: thrombophilia workup, HIT, recurrent VTE on therapy, anticoagulation in renal failure
— Cardiology / pulmonary: submassive/massive PE, RV dysfunction
— Interventional radiology: catheter-directed thrombolysis, IVC filter, mechanical thrombectomy
— Anesthesiology: peripartum anticoagulation timing, neuraxial planning
— Cardiothoracic surgery: surgical embolectomy if thrombolysis fails or contraindicated
— Neonatology: anticipate preterm delivery, maternal medications
— Stable DVT in pregnancy can often be managed outpatient after initial LMWH dose and education, with close follow-up
— PE: most pregnant patients admitted for at least 24–48 hours for observation, even if hemodynamically stable
— Discharge criteria: stable vitals, normal oxygenation, demonstrated injection technique, follow-up arranged within 1 week
— IV access, oxygen, left lateral tilt if >20 weeks, continuous monitoring, fetal heart tones, immediate ECG and CXR, bedside echo if unstable
CCS pearl: Unstable pregnant patient with suspected PE → simultaneous orders: O₂, IV access ×2 large bore, IV UFH bolus + drip (do not wait for imaging), bedside echo, OB and ICU consult, type and screen, fetal monitoring. Empiric anticoagulation is appropriate when suspicion is high and imaging is delayed.
— Superficial venous thrombophlebitis
▸ Palpable tender cord along superficial vein; warmth, erythema
▸ Treat NSAIDs (avoid 3rd trimester), warm compresses; CUS to exclude extension into deep system
▸ If extensive (>5 cm) or within 3 cm of saphenofemoral junction → prophylactic LMWH ×4–6 weeks
— Septic pelvic thrombophlebitis
▸ Postpartum, persistent fever despite antibiotics, often after endometritis or cesarean
▸ Therapy: anticoagulation + broad-spectrum antibiotics ×7–10 days
— Ovarian vein thrombosis
▸ Right-sided flank/abdominal pain postpartum, fever, palpable cord-like mass
▸ Diagnose with CT or MR; treat with anticoagulation + antibiotics
— Cerebral venous sinus thrombosis (CVST)
▸ Postpartum headache, seizures, focal neuro signs, papilledema
▸ MRV is diagnostic; treat with anticoagulation despite intracranial blood (LMWH first-line)
— Splanchnic vein thrombosis (portal, mesenteric)
▸ Abdominal pain, ascites; rare but consider in postpartum with JAK2 mutation or other prothrombotic state
— Amniotic fluid embolism (AFE)
▸ Sudden cardiovascular collapse during labor/delivery with DIC and respiratory failure
▸ Not a thrombotic embolism — supportive care, transfusion, ICU; anticoagulation contraindicated during acute DIC bleeding phase
— Air embolism
▸ Rare; associated with placental abruption or uterine manipulation; sudden hypoxia and shock
Key distinction: PE vs AFE — PE typically has unilateral leg findings or risk factors and lacks DIC; AFE classically presents intrapartum with cardiovascular collapse + DIC + respiratory failure as a triad. Anticoagulation is the treatment for PE but harmful in AFE's bleeding phase.
Board pearl: Postpartum headache with focal neuro signs is CVST until proven otherwise — MRV, not just CT.
— Ruptured Baker cyst: acute calf pain, ecchymosis at medial malleolus ("crescent sign"); ultrasound differentiates
— Cellulitis: erythema, warmth, fever, leukocytosis; lymphangitic streaks
— Muscle strain or hematoma: history of exertion or trauma
— Lymphedema: bilateral, gradual, non-pitting, no pain
— Chronic venous insufficiency: bilateral, dependent edema, varicosities
— Compartment syndrome: severe pain out of proportion, paresthesias, tense compartments
— Peripartum cardiomyopathy: dyspnea, orthopnea, edema in 3rd trimester to 5 months postpartum; EF <45% on echo; BNP elevated
— Pneumonia: fever, productive cough, focal infiltrate
— Asthma exacerbation: wheezing, prior history; pregnancy worsens 1/3 of asthma
— Acute coronary syndrome / spontaneous coronary artery dissection (SCAD): pregnancy is a known SCAD risk factor — peripartum or postpartum chest pain with ST changes
— Aortic dissection: severe tearing pain, asymmetric BP/pulses; Marfan or hypertension increases risk
— Pneumothorax: sudden pleuritic pain, unilateral decreased breath sounds
— Anxiety / panic attack — diagnosis of exclusion
— Pulmonary edema from preeclampsia, tocolytic use, or fluid overload
— Pulmonary embolism from non-thrombotic source: amniotic fluid, air, fat
— Up to 70% of pregnant women experience dyspnea; gradual, exertional, no hypoxia, no tachycardia at rest
— Pathologic dyspnea: sudden, at rest, with tachycardia or hypoxia — always evaluate
Key distinction: Peripartum cardiomyopathy vs PE — both cause postpartum dyspnea, but cardiomyopathy presents with bilateral crackles, S3, low EF on echo, while PE typically has clear lungs and RV dysfunction with preserved LV on echo.
Board pearl: Postpartum woman with chest pain + ST changes → think SCAD, not just classic ACS — pregnancy is the dominant risk factor in this demographic.
— Minimum 3 months total AND continue throughout pregnancy + at least 6 weeks postpartum
— Whichever yields the longer duration governs
— VTE late in pregnancy → may extend treatment to 3 months postpartum
— LMWH continued — safe in lactation; convenient if patient already established
— Warfarin — safe in breastfeeding (not secreted in clinically significant amounts); target INR 2–3; overlap with LMWH for ≥5 days AND until INR ≥2 for 24 hours
— DOACs — generally avoided during breastfeeding due to limited data; if not breastfeeding, can be considered after delivery
— Graduated compression stockings for established DVT to reduce PTS risk (evidence mixed but commonly recommended)
— Early ambulation, hydration, leg elevation
— Smoking cessation counseling
— Women with pregnancy-associated VTE have substantial recurrence risk (~5–15%) in subsequent pregnancies
— All future pregnancies require antepartum prophylaxis + 6 weeks postpartum, regardless of provoked status of index VTE
— Estrogen-containing contraceptives are contraindicated; recommend progestin-only pills, levonorgestrel IUD, copper IUD, or barrier methods
— Defer routine testing during acute thrombosis and anticoagulation (false positives/negatives)
— Test ≥6 weeks postpartum and off anticoagulation ≥2 weeks, ideally before next conception
— Test only when results will change management
Step 3 management: At discharge after pregnancy-associated VTE, the plan is: (1) continue therapeutic anticoagulation 3 months minimum + through 6 weeks postpartum, (2) counsel against estrogen contraception, (3) plan prophylaxis for any future pregnancy, (4) defer thrombophilia testing.
— Week 1 post-diagnosis: clinic or phone check — confirm injection technique, adherence, no bleeding; review labs (CBC, creatinine)
— Week 2–4: in-person visit with MFM/hematology; review symptom resolution, leg measurement, fetal status
— Monthly thereafter until delivery; coordinate delivery planning by 36 weeks
— Postpartum 1–2 weeks: confirm anticoagulation transition (LMWH → warfarin or continued LMWH), bleeding assessment
— 6 weeks postpartum: standard postpartum visit + anticoagulation decision (stop vs continue)
— 3 months: reassess if anticoagulation can be discontinued (minimum duration reached)
— CBC at baseline, day 5–10 (HIT screen if UFH or transitioning), then periodically
— Creatinine every trimester (LMWH clearance)
— Anti-Xa levels in selected patients (extremes of weight, renal impairment, recurrent VTE on therapy) — peak 4 h post-dose, target 0.6–1.0 IU/mL for therapeutic q12h
— INR if on warfarin postpartum: weekly until stable, then monthly
— Bone density: consider if prolonged UFH; less concern with LMWH
— Subcutaneous injection technique; rotate sites; avoid abdomen near uterus late in pregnancy (use thighs)
— Bleeding precautions: soft toothbrush, electric razor, avoid NSAIDs
— Signs of recurrence: new leg swelling, chest pain, dyspnea — return immediately
— Hold dose if active bleeding or imminent delivery; contact provider
— Carry anticoagulant ID card
— Graduated compression stockings (20–30 mmHg or 30–40 mmHg) on affected leg, daily for ≥2 years
— Walking program, leg elevation when seated
Board pearl: Missed LMWH dose: if within 12 hours of scheduled, take immediately; if closer to next dose, skip — never double up. Document teaching at discharge.
— Document that risk of missed PE (maternal and fetal death) substantially exceeds radiation risks of CTPA or V/Q
— Discuss fetal radiation dose (<5 mSv from either modality, well below 50 mSv threshold for teratogenicity)
— Address maternal breast radiation with CTPA — meaningful for young patients with dense, lactating tissue
— Maternal autonomy is paramount; if patient refuses imaging, document discussion of risks and consider empiric anticoagulation if suspicion is high
— Discuss bleeding risk (intracranial, placental abruption, postpartum hemorrhage)
— Maternal benefit dominates; in arrest, consent is implied
— Document multidisciplinary discussion when feasible
— Discharge from acute care to outpatient anticoagulation: ensure prescription filled, follow-up scheduled within 1 week, teaching documented
— Peripartum handoff between OB, anesthesia, and inpatient teams: anticoagulant timing must be explicitly communicated to prevent neuraxial hematoma — a sentinel patient safety event
— Postpartum discharge with continued anticoagulation: ensure patient understands medication transition, bleeding precautions, when to call
— Maternal near-miss or mortality from VTE may trigger state maternal mortality review committee reporting (varies by state)
— Adverse drug event (HIT, major bleeding) → root cause analysis; report to FDA MedWatch when appropriate
— Black women in the US have 2–3× higher maternal mortality, with VTE contributing — recognize and address systemic gaps in prophylaxis use and access to follow-up
— Ensure interpretation services for anticoagulation teaching
— Capacitated patient may decline prophylaxis after counseling; document risk discussion, offer mechanical prophylaxis as alternative
Step 3 management: Before any neuraxial procedure, the single most important safety check is verifying time since last anticoagulant dose — a missed handoff here is the textbook cause of epidural hematoma and permanent paralysis.
— Pregnancy increases VTE risk 4–5×; postpartum first 6 weeks ~20× baseline
— Postpartum risk elevated through 12 weeks
— 85% of pregnancy DVT is left-sided, often iliofemoral
— Prophylactic enoxaparin 40 mg SC daily; therapeutic 1 mg/kg SC q12h
— Hold therapeutic LMWH 24 h before neuraxial; prophylactic 12 h
— Hold UFH 4–6 h with normal aPTT before neuraxial
— Minimum treatment duration 3 months AND through 6 weeks postpartum
— Perimortem cesarean within 4 minutes of maternal arrest at ≥23 weeks
— Left iliofemoral DVT ↔ May-Thurner anatomy + gravid uterus
— Recurrent pregnancy loss + thrombosis ↔ antiphospholipid syndrome
— Postpartum fever unresponsive to antibiotics ↔ septic pelvic thrombophlebitis
— Postpartum headache + seizure ↔ CVST (or eclampsia — image both)
— Right flank pain postpartum ↔ ovarian vein thrombosis (right > left)
— Sudden intrapartum collapse + DIC ↔ amniotic fluid embolism
— Peripartum dyspnea + low EF ↔ peripartum cardiomyopathy
— OHSS post-ART ↔ upper extremity / IJ venous thrombosis (unusual sites)
— LMWH safe in pregnancy and lactation
— Warfarin teratogenic (6–12 wk); safe postpartum/lactation
— DOACs avoided pregnancy and lactation
— Aspirin 81 mg safe; used in APS and preeclampsia prevention
— Suspected PE + leg symptoms → bilateral leg CUS first
— Normal CXR → V/Q; abnormal CXR → CTPA
— No combined estrogen ever; use progestin-only, IUD (Cu or LNG), or barrier
Board pearl: "Pregnant patient + left leg swelling + dyspnea" — answer is bilateral leg CUS, then CTPA or V/Q if CUS negative, then therapeutic LMWH. Memorize this triad sequence.
— "28-year-old G2P1 at 8 weeks. Prior unprovoked DVT 3 years ago, off anticoagulation. What is the next step?"
— Answer: Start prophylactic LMWH now, continue through pregnancy + 6 weeks postpartum
— "Pregnant patient at 24 weeks with 2 days of left calf pain and swelling, 3 cm calf size difference"
— Answer: Compression ultrasound (not D-dimer)
— Follow-up: therapeutic enoxaparin 1 mg/kg SC q12h
— "Pregnant patient at 32 weeks with sudden dyspnea, HR 120, SpO₂ 92%, clear lungs, unilateral leg swelling"
— Answer: Bilateral lower extremity CUS first; if negative, V/Q (if normal CXR) or CTPA
— "Pregnant patient at 30 weeks with PE, BP 70/40, tachycardia 140, hypoxia"
— Answer: Systemic thrombolysis (tPA) despite pregnancy
— "Patient on therapeutic LMWH, scheduled induction at 39 weeks. When to hold last dose?"
— Answer: 24 hours before induction/neuraxial
— "G3P0 with 3 prior 1st-trimester losses and one fetal demise at 22 weeks. Lupus anticoagulant + on 2 occasions"
— Answer: Prophylactic LMWH + low-dose aspirin throughout pregnancy + 6 weeks postpartum
— "POD #5 after cesarean, persistent fevers despite broad antibiotics, pelvic tenderness, normal exam"
— Answer: Septic pelvic thrombophlebitis → add heparin to antibiotics; CT/MR to confirm
— Answer: Avoid combined estrogen; offer progestin-only or IUD
— Pregnancy-associated VTE → antepartum + postpartum prophylaxis in all subsequent pregnancies
Board pearl: When a stem describes a pregnant patient with any unilateral leg swelling, the first diagnostic step is compression ultrasound, not D-dimer and not CTPA. This is the single most common right answer in this topic.
VTE is a leading cause of maternal mortality in the US; LMWH is the cornerstone of both prophylaxis and treatment throughout pregnancy, with imaging (compression ultrasound first, then V/Q or CTPA) pursued aggressively because the risk of a missed PE exceeds any imaging risk, and anticoagulation must continue for at least 3 months and through 6 weeks postpartum.
— Suspected DVT or PE → compression ultrasound first
— Negative CUS with persistent PE suspicion → V/Q (normal CXR) or CTPA (abnormal CXR)
— D-dimer is not reliable for ruling out VTE in pregnancy
— Enoxaparin 1 mg/kg SC q12h therapeutic; 40 mg SC daily prophylactic
— Warfarin and DOACs are contraindicated in pregnancy; warfarin safe postpartum/lactation
— Minimum 3 months treatment AND continue through 6 weeks postpartum
— Hold therapeutic LMWH 24 h, prophylactic 12 h before neuraxial
— Bridge to UFH near term in high-risk patients
— Resume 6–12 h postpartum once hemostasis confirmed; remove epidural catheter before therapeutic restart
— All future pregnancies after pregnancy-associated VTE require antepartum prophylaxis + 6 weeks postpartum
— No estrogen-containing contraception
— Defer thrombophilia testing until ≥6 weeks postpartum, off anticoagulation, when results will change management
— Counsel on PTS prevention with graduated compression stockings
Step 3 management: The exam-day triad — suspect → ultrasound → LMWH — solves nearly every VTE-in-pregnancy question; remember that maternal stabilization always precedes fetal considerations, and that anticoagulation timing around neuraxial anesthesia is the single highest-stakes patient safety checkpoint of this topic.