Maternal Serum and Cord Blood Leptin Concentrations in African Newborns: Relationship to Birth Weight and Gender

Background: Leptin, a protein predominantly produced by adipocytes, plays a crucial role in regulating energy balance, inflammation, immunity, and fetal growth. During pregnancy, maternal serum leptin levels increase, peaking in the second trimester, with placental production contributing to this rise. Leptin has also been identified in fetal tissues, and its concentration in umbilical cord blood correlates with birth weight. This study aimed to evaluate serum and umbilical cord blood leptin concentrations in rural Burundian women living in marginal nutritional conditions, and investigate potential gender differences in fetal leptin levels. Methods: We analyzed data from 38 healthy singleton pregnancies (20 male and 18 female newborns) delivered at Hôpital Autonome de Ngozi, Burundi. Leptin concentrations were measured in maternal and umbilical cord blood samples. Results: Our results revealed that neonatal leptin levels were significantly higher in female compared to male newborns, consistent with findings in other populations. Leptin concentrations in umbilical cord blood were positively correlated with neonatal birth weight and the Kaup index, while maternal leptin levels did not show such associations. Conclusions: Despite the challenging nutritional environment in this rural African setting, our findings suggest that leptin’s role in fetal growth regulation may transcend maternal nutritional status. The gender difference observed in leptin levels could be linked to genetic or epigenetic factors rather than fat content or reproductive hormones. This study supports the notion that leptin may be an important regulator of fetal development, even in malnourished populations, and underscores the need for further research to elucidate its mechanisms in pregnancy.