Uneventful delivery of two pregnancies in a woman with severe factor XII deficiency: case report and systematic review

Background: Deficiency of factor XII (FXII) is widely considered to have a detrimental effect on pregnancy. Several reports underline the increased risk for antenatal complications with few published case reports of uncomplicated deliveries. The main objective of our article is to perform a systematic review to highlight pregnancies with severe deficiency of FXII that have been delivered uneventfully, along with presenting our relative case of a woman with severe deficiency of FXII. Materials and methods: A systematic review was performed in the Pubmed database. Inclusion criteria were considered to be case reports and case series presenting delivery of uncomplicated pregnancies in women with severe FXII deficiency. Medical records of our patient were also reviewed in terms of signs and symptoms, laboratory and imaging examinations and neonatal outcomes. Results: There were 62 abstracts derived while 44 were assessed for eligibility. There were finally three case reports of women with FXII deficiency delivering live newborns and one case series of 12 women with a final outcome of 19 deliveries. Regarding our case presentation, the woman with FXII levels < 12%, after a neonatal death because of extreme prematurity (24 weeks + 4 days), was set in regular follow-up and treatment with bemiparin natriate, 3.5 mg/kg and acetylsalicylic acid, 100 mg/day. She finally managed to have her second pregnancy delivered at 38 weeks + 3 days, her third pregnancy ended up as a miscarriage and her fourth pregnancy was also delivered at 37 weeks + 4 days. Conclusion: Despite the increased risk for antenatal complications, appropriate follow-up of pregnancies with severe FXII pregnancy may finally lead to an uneventful delivery.