PB1406 - A Tertiary Centre Experience of Late Amniocentesis in Obstetric Management of Women with Inherited Bleeding Disorders

Background: The significant risk of birth-trauma to affected foetuses of women with inherited bleeding disorders (IBD) is well-recognised. In absence of the knowledge whether the foetus is affected or not, a restrictive approach of avoiding standard obstetric-interventions that increase foetal bleeding-risk is adopted . Consequently, women with unaffected foetuses may be unnecessarily subjected to restrictive birth-plans. Knowledge of foetal mutation status is key in avoiding this. Pre-natal diagnosis is not always acceptable because of associated risk of miscarriage.
Ultrasound sexing can reduce the risk by 50% in haemophilia carriers but pregnancies with unaffected male foetus are unnecessarily subject to restrictive plans. It cannot be used in autosomal recessive conditions.

Aims: To present the experience of late amniocentesis at > 34 weeks gestation at our Tertiary Obstetric Bleeding Disorders Clinic.

Methods: Late amniocentesis was offered to women carrying a potentially affected foetus. Foetal diagnosis was confirmed by presence or absence of familial mutation.17 late amniocenteses were performed in women with IBD who had an identifiable mutation: 15 in haemophilia A carriers, and 2 in Type 2 vWD. 9 women had a single pregnancy, while 4 women had 2 pregnancies.

Results: The result informed birth-plans in 15/17 (88%) cases. The foetus was found to be affected in 4/17 cases (23.5%). A total of 11/17 foetuses (64.7%) were found to be unaffected, facilitating normal management of delivery in local-hospitals. The result could not be obtained in 2 cases due to poor DNA quality. In one case the amniocentesis was technically challenging due to foetal-position and was re-attempted successfully at a later date.

Conclusion(s): Late amniocentesis is a valuable technique in obstetric management of selected women with IBD. It has a significantly positive impact in clinical decision-making and in guiding management of labour and delivery in women who decline early prenatal diagnosis or in those who present late.