title: A descriptive evaluation of unfractionated heparin use during pregnancy.
abstract: BACKGROUND
  The mainstay of oral anticoagulant therapy, warfarin sodium, crosses the placenta during pregnancy and may cause fetal complications. Unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) do not cross the placenta and have demonstrated utility in the prevention and treatment of thrombosis during pregnancy.
  
  
  OBJECTIVE
  The purpose of this study was to review treatment strategy, indication, and maternal and fetal outcomes in anticoagulated pregnancies at Kaiser Permanente Colorado.
  
  
  METHODS
  We identified 103 pregnancies in 93 mothers prescribed an anticoagulant during a pregnancy occurring between January 1, 1998 and March 31, 2005.
  
  
  RESULTS
  The majority of patients were treated with UFH (89.3%). Indications for anticoagulation included venous thromboembolism (VTE) prophylaxis (53.4%), history of pregnancy loss (29.1%), acute VTE (16.5%), and history of cerebral vascular accident (CVA) (1.0%). There were no maternal deaths. Fetal demise occurred in 8 pregnancies (7.8%) at a median 14 weeks gestation (range 7-22 weeks). No fetal demise occurred in pregnancies treated for acute VTE or history of CVA. There were two occurrences of pulmonary embolism (1.9%) and two hemorrhagic events requiring transfusion (1.9%).
  
  
  CONCLUSIONS
  Maternal and fetal adverse events were infrequent in our population of anticoagulated pregnancies. UFH remains a viable option among more expensive LMWH products.
authors.affiliation: Clinical Pharmacy Anticoagulation Service, Kaiser Permanente Colorado, Lafayette, CO 80026, USA. nathan.clark@kp.org
authors.forename: Nathan P
authors.initials: NP
authors.lastname: Clark
authors.forename: Thomas
authors.initials: T
authors.lastname: Delate
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Witt
authors.forename: Suzanne
authors.initials: S
authors.lastname: Parker
authors.forename: Robert
authors.initials: R
authors.lastname: McDuffie
mesh_terms: D000328:Adult; D000925:Anticoagulants / Q000627:therapeutic use; D005260:Female; D005313:Fetal Death; D005333:Fetus / Q000187:drug effects*; D006470:Hemorrhage; D006493:Heparin / Q000627:therapeutic use*; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D011247:Pregnancy; D011248:Pregnancy Complications / Q000188:drug therapy / Q000517:prevention & control*; D011292:Premedication / Q000379:methods; D011655:Pulmonary Embolism; D012189:Retrospective Studies; D015996:Survival Rate
chemical_list: D000925:Anticoagulants; D006493:Heparin