Antiphospholipid antibodies associated with recurrent pregnancy loss: prospective, multicenter, controlled pilot study comparing treatment with low-molecular-weight heparin versus unfractionated heparin

Fertil Steril. 2005 Mar;83(3):684-90. doi: 10.1016/j.fertnstert.2004.11.002.


Objective: To evaluate the use of low-molecular-weight heparin (LMWH) in combination with low-dose aspirin (LDA) for the treatment of antiphospholipid antibody (APA)-associated recurrent pregnancy loss and to compare the results with the use of unfractionated heparin (UFH) plus LDA.

Design: Prospective, controlled, multicenter pilot study.

Setting: Two academically based reproductive health centers.

Patient(s): Patients with three or more pregnancy losses and positive APA.

Intervention(s): Patients were treated with LMWH and LDA (n = 25) or UFH and LDA (n = 25).

Main outcome measure(s): Fetal outcome and maternal complications from treatments were compared between the two treatment groups.

Result(s): Of the 25 patients in the LMWH group, 21 (84%) delivered a viable infant and 4 (16%) miscarried. Of the 25 patients in the UFH group, 20 (80%) delivered a viable infant and 5 (20%) miscarried. These differences were not statistically significant. No major bleeding episodes occurred during pregnancy or at the time of delivery. No cases of deep venous thrombosis, thrombocytopenia, pre-eclampsia, gestational diabetes, or bone fractures were noted in either of the two groups.

Conclusion(s): In this pilot study, the use of LDA in combination with LMWH during pregnancy for the prevention of recurrent pregnancy loss in women with antiphospholipid syndrome seems to be as safe as UFH plus LDA. Large, randomized trials will be required to determine differences in outcome with LMWH and LDA compared with treatment with UFH combined with LDA in this group of patients.

Publication types

  • Clinical Trial
  • Comparative Study
  • Controlled Clinical Trial
  • Multicenter Study

MeSH terms

  • Abortion, Habitual / immunology*
  • Abortion, Habitual / prevention & control*
  • Adult
  • Antibodies, Antiphospholipid / blood*
  • Anticoagulants / administration & dosage*
  • Anticoagulants / adverse effects
  • Aspirin / administration & dosage
  • Aspirin / adverse effects
  • Drug Therapy, Combination
  • Female
  • Heparin, Low-Molecular-Weight / administration & dosage*
  • Heparin, Low-Molecular-Weight / adverse effects
  • Humans
  • Pilot Projects
  • Platelet Aggregation Inhibitors / administration & dosage
  • Platelet Aggregation Inhibitors / adverse effects
  • Pregnancy
  • Pregnancy Complications / immunology
  • Pregnancy Complications / prevention & control
  • Pregnancy Outcome
  • Premature Birth
  • Prospective Studies


  • Antibodies, Antiphospholipid
  • Anticoagulants
  • Heparin, Low-Molecular-Weight
  • Platelet Aggregation Inhibitors
  • Aspirin