[Leptin during pregnancy].

OBJECTIVE

Leptin, the protein encoded by the Ob gene in the adipose cell, is produced by the placenta during pregnancy. This review describes recent findings regarding the putative functions of leptin during pregnancy.

MATERIAL

and methods. We searched the literature consulting Medline database.

RESULTS

Placental leptin production makes a substantial contribution to maternal circulating levels during pregnancy. Leptin has been detected in fetal plasma as early as week 18 of gestation, and umbilical leptin concentrations are closely related to birth weight. This has led to the hypothesis that fetal fat mass mainly determines fetal circulating leptin. Placental leptin production is increased in choriocarcinoma, preeclampsia and type 1 diabetes. Estrogens, hypoxia and insulin have been suggested as positive regulators of placental leptin production.

CONCLUSION

Maternal leptinemia might act as a sensor of energy balance during pregnancy. The presence of both leptin and leptin receptors in the placenta suggests that leptin can act by autocrine or endocrine pathways in the human placenta. The roles of fetal leptin and consequences of increased placental leptin production in pathological pregnancies have yet to be elucidated.