Table 2.

Mitochondrial competence of day 4 embryos

	Number of embryos	Maternal age (yo)	OCRs (fmol/s)	Maximum OCRs (fmol/s)	Copy number of mtDNA	OCR/mtDNA (fmol/s)
Morula	15	35.4	1.79a	3.75a	103,773	1.8 × 10−5a
≥10	11	31.4	1.51ab	3.43ab	126,107	1.31 × 10−5a
<10	10	33.6	0.91b	2.41b	175,044	0.61 × 10−5b

^a,b p < 0.01 by Kruskal-Wallis test following ANOVA