title: Low-molecular-weight heparin for prevention of placenta-mediated pregnancy complications: protocol for a systematic review and individual patient data meta-analysis (AFFIRM).
abstract: BACKGROUND
  Placenta-mediated pregnancy complications include pre-eclampsia, late pregnancy loss, placental abruption, and the small-for-gestational age newborn. They are leading causes of maternal, fetal, and neonatal morbidity and mortality in developed nations. Women who have experienced these complications are at an elevated risk of recurrence in subsequent pregnancies. However, despite decades of research no effective strategies to prevent recurrence have been identified, until recently. We completed a pooled summary-based meta-analysis that strongly suggests that low-molecular-weight heparin reduces the risk of recurrent placenta-mediated complications. The proposed individual patient data meta-analysis builds on this successful collaboration. The project is called AFFIRM, An individual patient data meta-analysis oF low-molecular-weight heparin For prevention of placenta-medIated pRegnancy coMplications.
  
  
  METHODS
  We conducted a systematic review to identify randomized controlled trials with a low-molecular-weight heparin intervention for the prevention of recurrent placenta-mediated pregnancy complications. Investigators and statisticians representing eight trials met to discuss the outcomes and analysis plan for an individual patient data meta-analysis. An additional trial has since been added for a total of nine eligible trials. The primary analyses from the original trials will be replicated for quality assurance prior to recoding the data from each trial and combining it into a common dataset for analysis. Using the anonymized combined data we will conduct logistic regression and subgroup analyses aimed at identifying which women with previous pregnancy complications benefit most from treatment with low-molecular-weight heparin during pregnancy.
  
  
  CONCLUSIONS
  The goal of the proposed individual patient data meta-analysis is a thorough estimation of treatment effects in patients with prior individual placenta-mediated pregnancy complications and exploration of which complications are specifically prevented by low-molecular-weight heparin.
  
  
  BACKGROUND
  PROSPERO (International Prospective Registry of Systematic Reviews) 23 December 2013, CRD42013006249.
authors: The Ottawa Hospital, Centre for Practice-Changing Research, 501 Smyth Road, Box 201, Ottawa, ON K1H 8 L6, Canada. mrodger@ohri.ca.
authors: Marc A
authors: MA
authors: Rodger
authors: Nicole J
authors: NJ
authors: Langlois
authors: Johanna Ip
authors: JI
authors: de Vries
authors: Evelyne
authors: E
authors: Rey
authors: Jean-Christophe
authors: JC
authors: Gris
authors: Ida
authors: I
authors: Martinelli
authors: Ekkehard
authors: E
authors: Schleussner
authors: Timothy
authors: T
authors: Ramsay
authors: Ranjeeta
authors: R
authors: Mallick
authors: Becky
authors: B
authors: Skidmore
authors: Saskia
authors: S
authors: Middeldorp
authors: Shannon
authors: S
authors: Bates
authors: David
authors: D
authors: Petroff
authors: Dick
authors: D
authors: Bezemer
authors: Marion E
authors: ME
authors: van Hoorn
authors: Carolien Nh
authors: CN
authors: Abheiden
authors: Annalisa
authors: A
authors: Perna
authors: Paulien
authors: P
authors: de Jong
authors: Risto
authors: R
authors: Kaaja
mesh_terms: D005260:Female; D017408:Guidelines as Topic; D006495:Heparin, Low-Molecular-Weight / Q000627:therapeutic use*; D006801:Humans; D016247:Information Storage and Retrieval; D010922:Placenta Diseases / Q000517:prevention & control*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000209:etiology / Q000517:prevention & control*; D016032:Randomized Controlled Trials as Topic; D012196:Review Literature as Topic; D000078202:Systematic Reviews as Topic; D015201:Meta-Analysis as Topic
chemical_list: D006495:Heparin, Low-Molecular-Weight