Table 1.

Findings^* in pregnancies that had fetal karyotyping by chorionic villous sampling (CVS)

		CVS qf-PCR result
Final karyotype after CVS and further investigation	Total (n=17 446)	Abnormal (n=1691)	Normal (n=15 755)
No risk or low risk of adverse outcome:	15 724 (90.1%)	6 (0.04%)	15 718 (99.96%)
Normal karyotype 46,XY or 46,XX	15 548	-	15 548
Abnormal karyotype:	176	6	170
Normal variants	8	-	8
Duplications and deletions (with good outcome)	6	-	6
Marker chromosomes (inherited)	2	-	2
Balanced rearrangements (inherited)	50	-	50
Balanced rearrangements (de novo)	15	-	15
Mosaic balanced rearrangements	2	-	2
CPM trisomies 2, 4, 6, 7, 8, 9, 10, 12, 15, 16, 19, 20, 22	18	-	18
CPM mosaic trisomies 2, 4, 6, 7, 8, 9, 10, 12, 15, 16, 19, 20, 22	46	-	46
CPM mosaic trisomies 13, 18, 21	12	3	9
CPM mosaic duplications or deletions	6	-	6
CPM mosaic marker chromosomes	2	-	2
CPM mosaic sex aneuploidies	9	3	6
High risk of adverse outcome:	1722 (9.9%)	1685 (97.9%)	37 (2.1%)
Group A—all detected by qf-PCR:	1667	1667	0
Trisomy 13	138	138	-
Trisomy 18	336	336	-
Trisomy 21	936	936	-
Turner	134	134	-
Other sex aneuploidies	53	53	-
Monosomy 21	1	1	-
Triploidy	69	69	-
Group B—some detected by qf-PCR:	30	18	12
Mosaic trisomies 13, 18, 21	3	2	1
Mosaic sex aneuploidies	5	1	4
Unbalanced rearrangements	22	15	7
Group C—none detected by qf-PCR:	25	0	25
Trisomies 8, 9, 15, 16, 20, 22	5	-	5
Duplications and deletions	13	-	13
Marker chromosomes (de novo)	1	-	1
Mosaic trisomies 8, 9, 20, 22	1	-	1
Mosaic duplications or deletions	4	-	4
Mosaic marker chromosomes (de novo)	1	-	1

CPM=confined placental mosaicism; qf-PCR=quantitative fluorescent polymerase chain reaction.

^*First two columns show result of fetal karyotype, which in some cases required additional investigations after initial CVS. Last two columns show CVS qf-PCR result. 33 cases in which necessary further investigations were not done are not listed.