Methods	EA versus TA CVS. Women eligible were given the choice as to randomisation or to decide the method of prenatal diagnosis themselves. Randomisation was performed using sequentially numbered envelopes
Participants	Women requesting prenatal diagnosis due to age related risk. 212 women were recruited, 115 agreed to be randomised; 70 chose EA and 25 CVS. 2 women did not participate because fetal death was diagnosed before any intervention
Interventions	TA CVS was performed using a 20 G needle. AC was performed using a 22 G needle: 11 ml of amniotic fluid was aspirated, the first ml being discarded
Outcomes	Technical difficulties, abnormal karyotype, pregnancy complications, perinatal loss, neonatal complications, Dutch version of Denver Developmental Screening Test at 6-9 months
Notes	Study stopped after 18 months following advice of the institutional ethical committee due to a higher incidence of fetal loss in the EA group
Risk of bias
Item	Authors’ judgement	Description
Allocation concealment?	Yes	A - Adequate