Introduction Thrombophilia has been linked to adverse pregnancy outcomes; however the timing and role of thrombophilia testing following pregnancy loss remains controversial. The RCOG guideline on late pregnancy loss advises thrombophilia testing at delivery whereas BSH guidance states the evidence for this is limited and conflicting. The aim of this study was to assess whether thrombophilia testing was performed at delivery following late pregnancy loss (and whether repeated if abnormal) and to assess whether genuine thrombophilia is associated with fetal growth restriction.

Methods Retrospective study of clinical and electronic records of women (n = 131) admitted to a tertiary centre delivery suite with late pregnancy loss, over an 18-month period. Thrombophilia test results were reviewed and correlated with evidence of fetal growth restriction from clinical data and post-mortem results where available.

Results 74% of patients had a thrombophilia test at delivery. Over 90% of the results were abnormal, the majority of which were low protein S. Only 17 out of 88 women with abnormal results had a repeat test at 6 weeks. 76 had a post mortem, with evidence of FGR in 13, 4 having a positive thrombophilia screen. The most common abnormality in normally grown babies was low protein S (normal at 6 weeks when repeated).

Conclusion Thrombophilia testing at delivery is likely to yield false positive results and is therefore of little value. Thrombophilia testing is also unnecessary in normally grown fetuses and should currently only be considered at 6 weeks after delivery if evidence of fetal growth restriction.