Research Article

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.

YearSingletonsMultiplesRR (95% CI)Total

20040.43 (88/20,304)0.97 (35/3,612)2.24 (1.51–3.30)0.50 (123/23,916)
20050.53 (119/22,524)0.92 (35/3,784)1.75 (1.20–2.55)0.59 (154/26,308)
20060.67 (165/24,787)1.52 (52/3,424)2.28 (1.67–3.11)0.77 (218/28,211)
20070.93 (240/25,944)1.92 (62/3,221)2.08 (1.58–2.74)1.04 (304/29,165)
20081.06 (322/30,372)2.10 (45/2,139)1.98 (1.46–2.70)1.13 (368/32,511)

Total0.75 (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.