Study designs of evaluations included in the review
All study designs including randomised (RCTs) and non-randomised controlled trials, cohort studies, case-reports, retrospective studies and letters to the editor. Abstracts were not included.
Specific interventions included in the review
LMWHs including dalteparin (2,500 - 22,000 U/day), mono-embolex (1,500 U single dose), LHN-1 (35 U/kg single dose), enoxaparin (20 mg (2,000 IU) - 80 mg (8,000 U)/day), nadroparin (2,050 - 15,000 U/day), certoparin (3,000 U/day), PK10619 (60 - 80 mg/day), Org 10172 (2,000 - 3,400 U/day), and heparin calcium (1,000 U/day). Dose regimens featured fixed dosages, increasing dosages as pregnancy progressed, dosages based on body weight, and dosages titrated according to anti-Xa levels. Duration of therapy varied from a single dose to 476 days. Other comparison treatments included unfractionated heparin.
Participants included in the review
Pregnant women requiring LMWH therapy for conditions including the prophylaxis and treatment of venous thromboembolism, recurrent miscarriage, impaired fibrinolytic capacity, antiphospholipid antibody syndrome, familial thrombophilia and other conditions. Women receiving LMWH therapy who subsequently became pregnant and those involved in placental transfer studies were also included.
Outcomes assessed in the review
Maternal anti-Xa levels; placental transfer anti-Xa levels; incidence of thromboembolic events including deep vein thrombosis (DVT) and pulmonary embolism (PE); adverse reactions (e.g. bleeding, osteoporosis, local/generalised skin reactions, thrombophlebitis etc.); foetal and maternal mortality.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review, or how many of the authors performed the selection.