title: Prophylaxis with low-dose low-molecular-weight heparin during pregnancy and postpartum: is it effective?
abstract: BACKGROUND
  The optimal approach for venous thrombosis (VTE) prophylaxis during pregnancy and postpartum in women with an increased risk of VTE is not established.
  
  
  OBJECTIVE
  To evaluate the effectiveness, represented as the incidence of pregnancy-related VTE, and safety, represented as incidence of postpartum hemorrhage (PPH), of a protocol recommending prophylaxis with low-dose low-molecular-weight heparin (LMWH) in women at intermediate to high risk of VTE.
  
  
  METHODS
  In this retrospective cohort study, we analyzed 34 women (44 pregnancies) with intermediate risk of VTE who received low-dose LMWH for 6 weeks postpartum and 57 women (82 pregnancies) with high risk of VTE who received low-dose LMWH during pregnancy and for 6 weeks postpartum. Pregnancy-related VTE was defined as VTE during pregnancy or ≤ 3 months postpartum. PPH was defined as blood loss >500 mL and severe PPH as blood loss > 1000 mL.
  
  
  RESULTS
  The incidence of pregnancy-related VTE was 5.5% (95% CI, 2.4-12.3) despite prophylaxis with low-dose LMWH. All events occurred in women at high risk, with a postpartum incidence of 7.0% (95% CI, 2.9-16.7) and antepartum incidence of 1.8% (95% CI, 0.4-9.2). The risk of PPH was 21.6% (95% CI, 14.3-31.3) and severe PPH 9.1% (95% CI, 4.7-16.9), which was not different in women who started LMWH postpartum and those who used LMWH during pregnancy.
  
  
  CONCLUSIONS
  Although prophylaxis with low-dose LMWH during pregnancy and postpartum proved to be safe, the risk of pregnancy-related VTE is considerable in women with a high risk of VTE. VTE prophylaxis with low-dose LMWH may not be sufficiently effective in these women.
authors.affiliation: Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands. j.roetersvanlennep@erasmusmc.nl
authors.forename: J E
authors.initials: JE
authors.lastname: Roeters van Lennep
authors.forename: E
authors.initials: E
authors.lastname: Meijer
authors.forename: F J C M
authors.initials: FJ
authors.lastname: Klumper
authors.forename: J M
authors.initials: JM
authors.lastname: Middeldorp
authors.forename: K W M
authors.initials: KW
authors.lastname: Bloemenkamp
authors.forename: S
authors.initials: S
authors.lastname: Middeldorp
mesh_terms: D000328:Adult; D000925:Anticoagulants / Q000009:adverse effects / Q000494:pharmacology; D015331:Cohort Studies; D005260:Female; D006495:Heparin, Low-Molecular-Weight / Q000009:adverse effects / Q000494:pharmacology*; D006801:Humans; D006473:Postpartum Hemorrhage / Q000209:etiology; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000517:prevention & control*; D011644:Puerperal Disorders / Q000517:prevention & control; D012189:Retrospective Studies; D012307:Risk Factors; D054556:Venous Thromboembolism / Q000150:complications / Q000517:prevention & control
chemical_list: D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight