Birth outcomes in pregnant women treated with low-molecular-weight heparin.
BACKGROUND
Pregnancy and puerperium are associated with an increased risk of venous thromboembolism. Low-molecular-weight heparin is the anticoagulant of choice in pregnant women because, unlike warfarin, it does not cross the placenta. However, there are limited data on the risk of adverse birth outcomes following use of low-molecular-weight heparin in pregnancy.


METHODS
We performed a population-based cohort study to examine the safety of low-molecular-weight heparin use in pregnancy using data from the Pharmacoepidemiological Prescription Database, The Danish Medical Birth Registry and the Regional Hospital Discharge Registry in North Jutland County, Denmark. The birth outcomes in a cohort of 66 pregnant women treated with low-molecular-weight heparin between 1991-98 were compared with the birth outcomes of 17,259 pregnant women who did not receive any prescriptive drugs during pregnancy.


RESULTS
No increased risk of malformations, low birth weight or stillbirth was found. However, an increased risk of pre-term delivery was found (odds ratio: 2.11, 95%, confidence interval: 0.96-4.65), which could reflect inherited thrombophilia as an indication of low-molecular-weight heparin.


CONCLUSIONS
We have provided additional evidence of the safety of low-molecular-weight heparin use in pregnancy.
Sørensen
H T
HT
The Danish Epidemiology Science Center at the Department of Medicine V, Aarhus University Hospital.
Johnsen
S P
SP
Larsen
H
H
Pedersen
L
L
Nielsen
G L
GL
Møller
M
M
D000014:Abnormalities, Drug-Induced; D000293:Adolescent; D000328:Adult; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use*; D015331:Cohort Studies; D005260:Female; D006495:Heparin, Low-Molecular-Weight / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D008875:Middle Aged; D007752:Obstetric Labor, Premature; D011247:Pregnancy; D011248:Pregnancy Complications / Q000517:prevention & control; D011256:Pregnancy Outcome; D020246:Venous Thrombosis / Q000517:prevention & control*
D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight