Comparison 4.

Transcervical versus transabdominal CVS

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Not complied with allocated procedure	3	5187	Risk Ratio (M-H, Random, 95% CI)	1.68 [0.59, 4.76]
2 Sampling failure	4	5231	Risk Ratio (M-H, Fixed, 95% CI)	1.82 [1.15, 2.86]
3 Multiple insertions	2	1314	Risk Ratio (M-H, Fixed, 95% CI)	2.73 [1.78, 4.17]
4 Second test performed	1	1194	Risk Ratio (M-H, Fixed, 95% CI)	1.24 [0.65, 2.37]
5 Laboratory failure	1	1194	Risk Ratio (M-H, Fixed, 95% CI)	2.23 [0.69, 7.22]
6 All non-mosaic abnormalities	1	2862	Risk Ratio (M-H, Fixed, 95% CI)	1.23 [0.87, 1.75]
7 True mosaics	1	2862	Risk Ratio (M-H, Fixed, 95% CI)	0.92 [0.39, 2.17]
8 Confined mosaics	1	2862	Risk Ratio (M-H, Fixed, 95% CI)	0.85 [0.26, 2.77]
13 Vaginal bleeding after test	3	1358	Risk Ratio (M-H, Random, 95% CI)	6.93 [0.77, 62.83]
14 Amniotic leakage after test	1	44	Risk Ratio (M-H, Fixed, 95% CI)	0.28 [0.01, 6.52]
20 All known pregnancy loss (including termination of pregnancy)	5	7978	Risk Ratio (M-H, Random, 95% CI)	1.16 [0.81, 1.65]
21 Termination of pregnancy (all)	2	1303	Risk Ratio (M-H, Fixed, 95% CI)	0.83 [0.56, 1.22]
24 Spontaneous miscarriage	4	3384	Risk Ratio (M-H, Random, 95% CI)	1.68 [0.79, 3.58]
25 Spontaneous miscarriage after test	3	1347	Risk Ratio (M-H, Fixed, 95% CI)	1.25 [0.76, 2.06]
26 Perinatal deaths	1	2037	Risk Ratio (M-H, Fixed, 95% CI)	0.44 [0.11, 1.68]
27 Stillbirths	2	1227	Risk Ratio (M-H, Fixed, 95% CI)	1.69 [0.38, 7.62]
28 Neonatal deaths	2	4845	Risk Ratio (M-H, Fixed, 95% CI)	0.60 [0.14, 2.49]
30 Anomalies (all recorded)	2	3622	Risk Ratio (M-H, Fixed, 95% CI)	0.68 [0.41, 1.12]
31 Talipes	1	2624	Risk Ratio (M-H, Fixed, 95% CI)	3.21 [0.33, 30.80]