This is the third edition of this guideline, which was previously published in October 1996 and February 2000.
It is estimated that around 5% of pregnant population (approximately 30 000 women per annum in the UK) could be offered a choice of invasive prenatal diagnostic tests (amniocentesis or chorionic villus sampling). The aim of this guideline is to ensure that the timing and techniques for these procedures do not vary significantly between practitioners and healthcare settings, thereby minimising associated risks. The guideline will provide up-to-date information, based on clinical evidence, rates of miscarriage associated with the procedures, optimal techniques and timing, training and competence and clinical governance issues.
Amniocentesis is the most common invasive prenatal diagnostic procedure undertaken in the UK. Most amniocenteses are performed to obtain amniotic fluid for karyotyping and the majority are undertaken from 15 completed weeks (15+0) onwards. Amniocentesis performed before 15 completed weeks of gestation is referred to as ‘early.’
Chorionic villus sampling (CVS) is usually performed between 10 and 13 weeks of gestation and involves aspiration of placental tissue rather than amniotic fluid. CVS can be performed using either percutaneous transabdominal or the transcervical approach. Transabdominal CVS can be performed at gestations greater than 13 weeks.
This guideline is available to download as a pdf by clicking the link below.
