Birth Defects in Singleton versus Multiple ART Births in Japan (2004–2008)
Table 2
Crude percentage of birth defects in ART pregnancy according to plurality.
Year
Singletons
Multiples
RR (95% CI)
Total
2004
0.43 (88/20,304)
0.97 (35/3,612)
2.24 (1.51–3.30)
0.50 (123/23,916)
2005
0.53 (119/22,524)
0.92 (35/3,784)
1.75 (1.20–2.55)
0.59 (154/26,308)
2006
0.67 (165/24,787)
1.52 (52/3,424)
2.28 (1.67–3.11)
0.77 (218/28,211)
2007
0.93 (240/25,944)
1.92 (62/3,221)
2.08 (1.58–2.74)
1.04 (304/29,165)
2008
1.06 (322/30,372)
2.10 (45/2,139)
1.98 (1.46–2.70)
1.13 (368/32,511)
Total
0.75 (934/123,931)
1.42 (229/16,180)
1.88 (1.60–2.13)
0.83 (1,167/140,111)a
Numbers of ART pregnancies according to plurality were presented in the JSOG annual report.
aTotal number includes four subjects with unknown plurality.