Thromboembolism is associated with significant maternal morbidity and is a leading cause of death in pregnancy. We present a 26 year old, para 2 woman who attended the combined haematology/obstetric clinic. She was diagnosed with an extensive femoral DVT at 38 weeks gestation and was given therapeutic low molecular weight heparin (LMWH). Prior to delivery she had an inferior venocaval (IVC) filter placed to prevent clot migration to the lungs. She attended at 40 weeks for induction of labour for raised blood pressure from 36 weeks gestation and converted to i.v. heparin to reduce the risks of haemorrhage.
Despite their use for more than 45 years, IVC filters remain controversial. There are risks from insertion including thrombosis, tilting and caval perforation. As per MHRA guidelines IVC filter ideally need to be removed within 3 months of insertion. However filter retrieval would only be considered safe if sufficient regression of the thrombosis had occurred and assuming no difficulties in its retrieval. Following ultrasound checking of the thrombosis the filter was successfully removed.
Future counselling of the patient is important for two reasons. Firstly as postnatally clexane is converted to warfarin, the patient needs to be aware of the teratogenic risks of becoming pregnant whilst on warfarin. Secondly any future pregnancy will require antenatal and postnatal thromboprophylaxis.
To conclude IVC filters in pregnancy should be used with caution until further evidence based practice justifies their use.