What role does ApoB play in fertility?

Apolipoprotein B (ApoB) is the primary protein component of LDL and other atherogenic lipoproteins. Its role in fertility is indirect but relevant: elevated ApoB levels can indicate disrupted lipid homeostasis, which is linked to oxidative stress, endothelial dysfunction, and chronic inflammation—factors that may impair oocyte quality, sperm function, and implantation. In women with PCOS or endometriosis, higher ApoB has been associated with poorer fertility outcomes. In men, elevated ApoB/LDL correlates with reduced sperm motility and increased DNA fragmentation. However, the evidence is moderate: most data come from observational studies, not randomized controlled trials. A direct causal effect is not established. Furthermore, consumer DNA tests typically assess single SNPs in APOB (e.g., rs1042034), whose impact on fertility is minimal and not clinically actionable. A blood measurement of ApoB (mg/dL) is far more informative. Caveat: ApoB levels should always be interpreted in the context of the full lipid profile and reproductive history.