Leptin levels in amniotic fluid and maternal blood at mid-trimester: Relations to gestational age, fetal sex, fetal weight estimated by ultrasound, and maternal BMI

Lim, Young Koo; Song, Eun Seop; Song, Kyung Eun; Lim, Mun Hwan; Lee, Byoung Ick; Kim, Jong Wha; Choe, Won Sick

Abstract

OBJECTIVES
Leptin is a 16-kD protein encoded by the ob/ob gene and represent the amount of body fat. In pregnancy, it is thought to act in intrauterine fetal growth and energy metabolism. In this study, we investigated the effect of gestational age, fetal sex, maternal body mass index (BMI), and fetal weight estimated by ultrasound on amniotic fluid and maternal serum leptin levels at mid-trimester, respectively.
METHODS
Amniotic fluid and maternal blood sampling were collected from women who was performed for genetic amniocentesis at mid-trimester (n = 26). Leptin concentrations were measured by a specific radioimmunoassay (RIA) employing human recombinant leptin. Mean gestational age was 18.19+/-1.77 weeks. Mean maternal BMI was 23.83 +/-5.12kg/m2. Male fetus was 10, and female 16. Mean fetal weight estimated by ultrasound was 254.42+/-83.80gm.
RESULTS
Mean maternal leptin level( 12.49+/-4.46 ng/mL) was significantly higher than mean amniotic leptin level(5.06+/-3.20 ng/mL)( p = 0.0001) at mid-trimester. But there was no significant correlationship between maternal and amniotic leptin levels( p = 0.1376). Maternal leptin concentrations at mid-trimester were correlated positively with maternal BMI(y = 2.24 + 0.43 x, R2 = 0.494, p = 0.0103). In contrast, leptin levels in amniotic fluid did not correlate with maternal leptin levels, gestational age, fetal sex, maternal BMI, and fetal weight estimated by ultrasound respectively.
CONCLUSION
Maternal leptin level was higher than amniotic leptin level and could represent maternal fat mass. It was suggested that amniotic leptin level was not associated with several factors such as maternal, fetal, and amniotic factors.