Abstract
Objectives
This study audited pregnancies where the mother received tinzaparin (at any stage
before delivery), with a primary objective of determining the maternal safety of this
low molecular weight heparin when administered as treatment and/or prophylaxis; the
secondary objective was to audit fetal and neonatal safety in this cohort. Efficacy
outcomes were also recorded.
Study design
The audit period was 1996–2009; consecutive, retrospective pregnancy records at participating
hospitals were reviewed. For those records documenting tinzaparin use and pregnancy
outcome, information was extracted into a standardised case report form; these were
reviewed for adverse events, which were submitted for adjudication by independent
experts in obstetric medicine and haematology. Endpoints were presented using descriptive
statistics for all pregnancies, and by reason for tinzaparin use (treatment of venous
thromboembolism [VTE] and prophylaxis).
Results
There were 28 participating hospital centres in eight countries (Belgium, Canada,
Denmark, Ireland, Netherlands, Sweden, Spain and the UK). Data were collected from
1267 pregnancies (1120 women; 1303 fetuses); in 254 pregnancies the women received
tinzaparin as treatment (median dose 13,000 international units [IU]/day, range 3500–23,100 IU/day; median duration 72 days; 94.1% once-daily), and in 1013 pregnancies the women
received tinzaparin for prophylaxis (median dose 4500 IU/day, range 2500–21,811 IU/day, median duration 183 days, 94.6% once-daily). There were 871 (70.2%) vaginal
deliveries (78 assisted) and 369 (29.8%) caesarean sections (27 delivery data missing).
Overall, 495 (39.3%) women had neuraxial anaesthesia; however, there were no reported
associated haematomas. There were no maternal deaths. Of pregnancies with available
data (1060), 86.9% had blood loss ≤500 mL, 11.0% of >500 to ≤1000 mL, 0.9% >1000 to ≤1500 mL and 1.1% >1500 mL. There were 1245 (95.5%) live births, 15 (1.2%) stillbirths, 40 (3.1%) miscarriages
and 3 (0.2%) terminations. Six (0.5%) neonatal deaths occurred (five at <27 weeks,
one Ebstein's anomaly). No neonatal haemorrhages occurred. Adjudicated safety outcomes
included 125 (9.9%) ‘any bleeding’ cases considered related to tinzaparin; 16 (1.3%)
of these required medical intervention. In the treatment group, five (2%) recurrent
VTEs were reported and 10 (1%) occurred in the prophylaxis group.
Conclusions
These data provide reassuring maternal and fetal outcome information in pregnancies
exposed to tinzaparin.
Keywords
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Article info
Publication history
Published online: September 19, 2011
Accepted:
August 31,
2011
Received in revised form:
July 14,
2011
Received:
June 1,
2011
Identification
Copyright
© 2011 Elsevier Ireland Ltd. Published by Elsevier Inc. All rights reserved.
