The effect of low molecular weight heparin (dalteparin) on duration and initiation of labour.

Nazim Isma, Peter Svensson, Bengt Lindblad, Pelle Lindqvist

Research output: Contribution to journalArticlepeer-review


It has recently been reported that women treated with low molecular weight heparin (LMWH) during pregnancy had 3 h shorter duration of delivery. The aim of the present study was to evaluate whether LMWH (dalteparin) affects labour. From January 1996 to December 2005, 217 consecutive pregnancies, out of 34 216 newborn (prevalence 0.6%) that were given thromboprophylaxis with dalteparin (usually 5,000 IU once daily). These 217 consecutive pregnancies were compared to an unselected control group (n = 1,499) of gravidae. Main outcome was time in first and second stage of labour and gestational age at delivery. Among nulliparous women, there were significantly fewer women with prolonged first stage of labour as compared to controls (4.1% vs. 8.5%, P = 0.047). In addition, the duration of first stage of labour was 1 h shorter among those treated with LMWH (5.2 vs. 6.2 h, P = 0.06). There were no such differences among parous women. The risk of prematurity, profuse blood loss, and postpartum anaemia was almost doubled among those treated with LMWH (11.5% vs. 5.9%, P = 0.002, 10.6% vs. 5.9%, P < 0.001, and 12.9% vs. 8.7%, P = 0.048, respectively). Treatment with a prophylactic dose of LMWH (dalteparin) during pregnancy was related to fewer women with prolonged first stage of labour, but also to an increased risk of prematurity and blood loss complications.
Original languageEnglish
Pages (from-to)149-153
JournalJournal of Thrombosis and Thrombolysis
Publication statusPublished - 2010

Bibliographical note

The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Clinical Coagulation Research Unit (013242510), Unit for Clinical Vascular Disease Research (013242410), Pediatrics/Urology/Gynecology/Endocrinology (013240400)

Subject classification (UKÄ)

  • Cardiac and Cardiovascular Systems


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