Pregnancy and weaning regulate human maternal liver size and function

BACKGROUNDDuring pregnancy, the rodent liver undergoes hepatocyte proliferation and increases in size, followed by weaning-induced involution via hepatocyte cell death and stromal remodeling, creating a pro-metastatic niche. These data suggest a mechanism for increased liver metastasis in postpartum breast cancer patients. OBJECTIVESInvestigate if the human liver changes in size and function during pregnancy and weaning. METHODSAbdominal imaging was obtained in healthy women at early and late pregnancy, and post-wean. During pregnancy time points, endogenous glucose production was measured and fasting blood taken to measure bile acids. RESULTSIndependent of weight gain, most womens livers increased in size with pregnancy, returning to baseline post-wean. Putative roles for bile acids in liver growth were observed in pregnant women and rodents. CONCLUSIONSThe human liver is regulated by reproductive state with growth during pregnancy and volume loss post-wean. These findings may have broad implications for sex-specific liver diseases and cancer.