Thromboprophylaxis In Pregnancy

Pregnancy is a hypercoagulable state so it is always important to consider the need for thromboprophylaxis before pregnancy, at booking, if admitted to hospital, throughout the antenatal
period, at start of labour and once delivered.

Risk factors For Thrombosis
• Age >35 years old
• Early pregnancy BMI >30
• Smoker
• Parity ≥3
• Multiple pregnancy
• Assisted reproduction
• Gross varicose veins
• Paraplegia
• Sickle cell disease/SLE
• Nephrotic syndrome
• Some cardiac causes
• Past thromboembolism
• Thrombophilia
• Myeloproliferative diseases.
• Inflammatory bowel disease.
• Hyperemesis/dehydration
• Pre-eclampsia
• Immobility for ≥3 days e.g symphysis pubis dysfunction
• Ovarian hyperstimulation
• Major infection (e.g pyelonephritis, wound infection) so hospital admission
• Labor lasting >24h
• Mid-cavity forceps
• Elective caesarean
• Blood loss >1L/transfusion history
• Surgery in puerperium e.g evacuation of retained products of conception
• Postpartum sterilization
• Long travel time (≥4h)

• In all pregnant women avoid immobility and dehydration.
• For women with 3 or more persisting risk factors , consider antenatal and postnatal low molecular weight heparin (LMWH) prophylaxis, starting as early in pregnancy as possible as risk is throughout (risk is decreased by ≤60–70%).
• Continue normal dose prophylaxis when admitted in labor. Treat for 6 weeks postpartum, and supply graduated compression stockings postpartum.
• If BMI >40, or caesarean in labour, give LMWH for 7 days postpartum.

Thromboprophylaxis after vaginal delivery:

Risk factors: (Thrombophilia/past thromboembolism considered separately.) If BMI >40 offer treatment. Offer to all women with two of the risk factors mentioned above.

Treatment: Treat with low molecular weight heparin (LMWH) eg enoxaparin starting as soon as possible after delivery (as long as no postpartum haemorrhage and ≥4h after epidural catheter siting or removal—6h if that was traumatic).

Continue for 7 days including at home. 

Dose of enoxaparin: if the early pregnancy weight (EPW) is 50–90kg, give 40mg/24h SC; if EPW <50kg, give 20mg/24h sc; if EPW 91–130kg give 60mg/24h SC, if EPW 131–170kg give 80mg/24h SC, if EPW >170kg give 0.6mg/kg/24h SC. 

If heparin is contraindicated, use TED compression stockings (TED= transverse elastic graduated). 

If 3 or more risk factors give stockings and LMWH.

Women with past venous thromboembolism

(VTE ) ± thrombophilia: Action depends on risk:

• VH = very high; 
• HR = high risk;
• IR = intermediate risk.

• (VH) If recurrent VTE (+antiphospholipid syndrome or antithrombin deficiency) or already on long-term warfarin, use high-dose prophylactic LMWH, eg enoxaparin 40mg/12h SC if 50–90kg EPW (or 75% of weight adjusted therapeutic dose (WATD)). WATD=1mg/kg/12h (kg is the EPW), prenatally and 1.5mg/kg/24h postnatally. This is given prenatally. Withhold at onset of labour (halve to /24h the day before and the day of induction).

Give for 6wks postpartum or revert to warfarin day 5–7 postnatally.

• (HR) Previous VTE unprovoked/idiopathic or oestrogen (or pregnancy)-related; or VTE + (1st degree relative with VTE or thrombophilia); or VTE + documented thrombophilia: give LMWH antenatally and 6 weeks postpartum.

• (IR) If a single previous VTE provoked by major risk factor no longer present and no other risk factors give LMWH for 6wks postpartum (PP).