Birth Defects in Singleton versus Multiple ART Births in Japan (2004–2008)

Table 5

Crude early neonatal mortality rate as to birth defects (per 10,000 live births).

Year	ART	Total births	RR (95% CI)
2004	2.75 (5/18,168)	4.27 (474/1,110,721)	0.64 (0.27–1.56)
2005	4.19 (8/19,112)	3.78 (402/1,062,530)	1.11 (0.55–2.23)
2006	8.17 (16/19,587)	3.86 (422/1,092,674)	2.11 (1.28–3.48)
2007	4.08 (8/19,595)	3.95 (431/1,089,818)	1.03 (0.51–2.08)
2008	5.99 (13/21,704)	3.41 (372/1,091,156)	1.76 (1.01–3.05)
Total	5.09 (50/98,166)	3.86 (2,101/5,446,899)	1.32 (1.00–1.75)

Numbers of total ART live births were presented in the JSOG annual report.
Crude neonatal mortality rate of total births were calculated using vital statistics.