Longitudinal changes in leptin and adiponectin concentrations through uncomplicated pregnancy

Abstract Background: Leptin and adiponectin play an important role during normal gestation; they are implicated in energy metabolism, glucose utilization and inflammation. Osteocalcin is released into circulation during bone formation; it also affects glucose metabolism by regulating insulin secretion and sensitivity, possibly mediated by adiponectin. The aim of this study was to explore the longitudinal changes of leptin and adiponectin in pregnancy, and their associations with lipid profile, insulin and bone formation parameters in late pregnancy. Methods: Leptin, adiponectin, lipid status parameters, C-reactive protein (CRP), insulin, 25-hydroxyvitamin D, osteocalcin and procollagen type 1 aminoterminal propeptide (P1NP) were measured in the sera of 38 healthy pregnant women. The samples were obtained in the 1st, 2nd, early and late 3rd trimester, and post-partum. Results: Leptin was significantly increased in the 3rd trimester. The decrease of adiponectin was significant only in postpartum. Osteocalcin and P1NP increased in the late 3rd trimester and postpartum. Leptin was significantly positively correlated with body mass index (BMI), uric acid, insulin, osteocalcin, P1NP and CRP in the 3rd trimester; adiponectin was positively correlated with high-density lipoprotein (HDL) cholesterol, and negatively with BMI, glucose, osteocalcin, triglycerides and insulin. Multiple regression analysis showed that only HDL is independently associated with adiponectin. Conclusions: The results of our study suggest complex interactions of leptin and adiponectin with glucose, lipid and bone metabolism during pregnancy. Adiponectin might be part of the protective systems that counterbalance a transient proatherogenic state observed in pregnancy mainly by improving the HDL levels. The exact mechanisms and potential implications in pathological states of pregnancy remain unexplained and require further investigation.