[Serum leptin levels in normal pregnant women and their babies]

To investigate serum leptin levels in normal pregnant women and their babies.

Immunoradioassay was used to measure the serum levels of leptin in 10 non-pregnant women, 63 pregnant women (31 in the firs, 10 in the second, and 22 in the third trimester), 27 women at delivery, 18 women in the first week after delivery and in 18 newborns' cord serum. Serum leptin levels were correlated with body weight, body mass index (BMI), fasting insulin levels and lipids.

Serum insulin, cholesterol, triglyceride were increased since the second trimester during pregnancy. One week after delivery serum insulin but not cholesterol and triglicetride level was decreased to the levels of non-pregnancy. Serum leptin levels were (7.98 +/- 4.42) micrograms/L in non-pregnant women and (7.03 +/- 3.42) micrograms/L in the first trimester. Then the levels were increased to (13.97 +/- 8.03) micrograms/L in second trimester and (14.86 +/- 6.25) micrograms/L in the third trimester, (19.89 +/- 9.66) micrograms/L at the delivery time and returned to (10.86 +/- 9.18) micrograms/L in the first week after delivery, respectively. Cord serum leptin levels of newborns were (8.93 +/- 6.95) micrograms/L. Serum leptin levels in pregnant women were positively correlated with their body weight, BMI, fasting serum insulin and glycerol levels. Cord serum leptin levels was positively correlated with newborn birth weights as well as their insulin levels.

(1) Serum leptin levels increase in the second and third trimester, and may contribute to the inhibition of increased food intake, body weight and body fat. (2) Newborn serum leptin may come from themselves, and the levels were lower than those in their mothers. (3) Birth weight, possibly adiposity, as well as serum insulin positively regulates serum leptin levels in neonates as in adults.