Fig. 1

Distribution of mtDNA copy number from peripheral blood and cord blood. A Box-and-whisker plots show the distribution of peripheral blood mtDNA copy numbers in the mother (n = 149), father (n = 149), maternal grandmother (n = 148), maternal grandfather (n = 147), paternal grandmother (n = 149), and paternal grandfather (n = 149) groups. The Dunnett test showed that mothers’ numbers (control) are significantly lower than those of the other groups. B Box-and-whisker plots show the distribution of cord blood mtDNA copy numbers in the female (n = 68) and male newborn groups (n = 82). The Mann–Whitney U test showed that female newborns’ numbers are significantly lower than those of male newborns. Statistically significant differences were found when *p < 0.05 and **p < 0.01