Prophylactic dosing adjustment in pregnancy based upon measurements of anti-factor Xa levels.
OBJECTIVE
To determine the necessity for monitoring of anti-factor Xa levels in pregnant women taking low molecular weight heparin (LMWH).


METHODS
A review of a hematological database with chart review was undertaken to identify patients on LMWH. Levels were drawn monthly. They were considered suboptimal if prophylactic and therapeutic doses of LMWH had an anti-Xa value <0.2 U/mL and 0.6 U/mL, respectively. Variables of interest included age, parity, thrombophilias, and antiphospholipid antibody syndrome.


RESULTS
Of 30 patients, three required therapeutic-dose LMWH and 27 were on prophylaxis. Sixty-six percent on a therapeutic dose required a dose change, whereas 11% on a prophylactic dose were changed (p = 0.013). None of the variables were predictive of a need for change. One thromboembolic event was noted while on prophylactic-dose LMWH.


CONCLUSIONS
No single variable is predictive of a need for dose change. Patients on a therapeutic dose were more likely to need change.
Gyamfi
Cynthia
C
Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Columbia University, New York, NY 10029, USA. drcynthiagyamfi@yahoo.com
Cohen
Rachel
R
Desancho
Maria T
MT
Gaddipati
Sreedhar
S
D000328:Adult; D000925:Anticoagulants / Q000008:administration & dosage*; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D015951:Factor Xa / Q000032:analysis*; D065427:Factor Xa Inhibitors; D005260:Female; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage*; D006801:Humans; D016015:Logistic Models; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000188:drug therapy / Q000517:prevention & control*; D012189:Retrospective Studies; D013923:Thromboembolism / Q000517:prevention & control; D019851:Thrombophilia / Q000188:drug therapy; D020246:Venous Thrombosis / Q000517:prevention & control
D000925:Anticoagulants; D065427:Factor Xa Inhibitors; D006495:Heparin, Low-Molecular-Weight; D015951:Factor Xa