Leptin and pregnancy outcome

Leptin, a recently discovered hormone that is involved in the regulation of body weight, appears to be one of the hormonal factors that signal the bod y's readiness for sexual maturation and reproduction to the brain. The pres ent review focuses on clinical and experimental studies that describe the r oles of maternal and foetal leptin as predictive factors for the physiologi cal and pathophysiological development of the foetus during pregnancy, assi sted reproduction and neonatal life. Through evaluating alterations of mate rnal serum leptin levels, a physiological hyperleptinaemia has been observe d to occur, particularly during the second and third trimesters of pregnanc y, which is not associated with a decreased food intake or reduced metaboli c activity in the pregnant women. This state of leptin resistance is compar able to the condition in obesity. In contrast, hypoleptinaemia is suggested to be an indicator for the cessation of pregnancy, either naturally at ter m or as a result of pathology at any time during gestation. Thus, an approp riate maternal leptin level seems to be a prerequisite for a normal pregnan cy. The main source of foetal leptin is the still immature foetal adipose t issue. As intrauterine growth has been found to be independently associated with cord blood leptin level, it has been suggested that leptin plays a ro le as a regulator of foetal growth. During assisted reproduction cycles lep tin levels in the follicular fluid of patients may be also of predictive va lue, with low levels predicting therapeutic failure. Finally, the relevance of leptin to postnatal development is reviewed; leptin may be important fo r regulation of satiety and peripheral metabolism. In summary, leptin appea rs to be an important permissive factor that is involved in female reproduc tion. (C) 2000 Lippincott Williams & Wilkins.