Background:
Low-molecular weight heparin (LMWH) is used to prevent pregnancy-associated venous thromboembolism (PA-VTE). The efficacy of this approach is unclear and may depend on dose and choice of LMWH.
Aims:
To evaluate the efficacy and rate of complications with thromboprophylaxis using enoxaparin in a cohort women at risk of PA-VTE managed between 1998 and 2014 at National Women’s Hospital, a tertiary obstetric referral centre in Auckland, New Zealand (NZ).
Methods:
A retrospective, observational study of women who received thromboprophylaxis with enoxaparin for prevention of PA-VTE while under the care of the obstetric or maternal fetal medicine team at NWH from 1998 to 2014.
Results:
Two hundred and thirty pregnancies in 156 women were identified. In the majority of pregnancies (n=200; 87%), women received a single daily dose of 40mg enoxaparin. Low dose aspirin (100mg daily) was given in 84 pregnancies (n=54 women). There was one breakthrough VTE during pregnancy in the study group (0.4%). Two women suffered intracranial haemorrhages (ICH) on treatment, one of whom died. Both women had significant underlying comorbid conditions (Brain tumour, severe hypertension) as the primary cause of ICH. Postpartum haemorrhage (PPH) occurred in 20 (8.7%) of pregnancies, Blood or blood products were given in seven pregnancies (n=4 women) for either antepartum or postpartum haemorrhages. Neuroaxial analgesia/anaesthesia was used in 134 births (58%) including 75% of emergency caesarean sections.
Conclusion:
Thromboprophylaxis with enoxaparin dosed according to current local guidelines appears effective at preventing PA-VTE. The use of LMWH did not impact on the rates of epidural or spinal use for analgesia/anaesthesia. While rates of obstetric bleeding complications were similar to the local general obstetric population, serious non-obstetric bleeding occurred in two women, one of whom died as a result. We therefore do not support the use of higher doses of LMWH in this population.