Mitochondria fuel placental activity, with mitochondrial dysfunction implicated in several perinatal complications. We investigated placental mtDNA mutational load using NextGen sequencing in relation to birthweight and gestational length among 358 mother-newborn pairs. We found that higher heteroplasmy, especially in the hypervariable displacement loop region, was associated with shorter gestational length. Results were similar among male and female pregnancies, but stronger in magnitude among females. With regard to growth, we observed that higher mutational load was associated with lower birthweight-for-gestational age (BWGA) among females, but higher BWGA among males. These findings support potential sex-differential fetal biological strategies for coping with increased heteroplasmies.

线粒体促进胎盘活动，线粒体功能障碍与几种围产期并发症有关。我们使用 NextGen 测序研究了 358 对母婴中胎盘 mtDNA 突变负荷与出生体重和妊娠长度的关系。我们发现较高的异质性，特别是在高变位移环区域，与较短的妊娠长度相关。男性和女性怀孕的结果相似，但女性怀孕的幅度更大。关于生长，我们观察到较高的突变负荷与女性较低的胎龄出生体重 (BWGA) 相关，但男性较高的 BWGA 相关。这些发现支持了应对异质性增加的潜在性别差异胎儿生物学策略。