Longitudinal Analysis of Maternal Serum Leptin Levels during Pregnancy, at Birth and Up To Six Weeks after Birth: Relation to Body Mass Index, Skinfolds, Sex Steroids and Umbilical Cord Blood Leptin Levels

Abstract

Leptin is an important regulator of body fat mass and energy expenditure during adult life. The mechanisms by which maternal and fetal weight are regulated during pregnancy are poorly understood. In order to gain more insight into a potential role of leptin during gestation, a prospective, longitudinal study was carried out to measure leptin concentrations in maternal serum of 29 healthy women during pregnancy up to 6 weeks after birth and also in umbilical cord blood of their newborns. Leptin concentrations were measured using a specific RIA. In addition, estradiol, testosterone, and sex hormone binding globulin were determined using commercially available RIAs. The mothers’ skinfolds were determined at four sites using a Holtain caliper.Leptin levels increased continuously during pregnancy and reached 25.8 ± 14.7 ng/ml at 38–40 weeks. At birth, leptin concentrations were 23.5 ± 15.4 ng/ml. Three days after delivery a significant decrease of leptin levels to 10.6 ± 6.0 ng/ml was observed. Six weeks after birth the leptin concentration in maternal serum was 13.8 ± 8.6 ng/ml. At birth, maternal serum levels were significantly higher than levels in cord blood and did not correlate with leptin levels in cord blood or neonatal weight. Furthermore, leptin levels did not correlate with maternal sex steroids and sex hormone binding globulin levels. At 6–8 weeks of pregnancy, maternal leptin serum levels correlated significantly with BMI (r = 0.81). The correlation coefficients (leptin vs. BMI) dropped with increasing gestational age and at birth only a poor correlation persisted (r = 0.50). Six weeks after birth there was again a high correlation between leptin levels in maternal serum and BMI (r = 0.76). Subscapular skinfold thickness was correlated to leptin concentrations in maternal serum during the whole period of the investigation.In conclusion, maternal leptin levels continuously increased from 6–8 weeks up to 38–40 weeks of pregnancy. Maternal leptin levels decreased dramatically after birth. Six weeks after delivery, leptin levels were comparable to the values measured at the beginning of pregnancy. We hypothesize that leptin might play an important role during pregnancy and fetal development.

Leptin and phospholipid-esterified docosahexaenoic acid concentrations in plasma of women: observations during pregnancy and lactation

“…As in many other studies (Butte et al, 1997;Lage et al, 1999;Sattar et al, 1998;Schrubing et al, 1998;Tamura et al, 1998), plasma leptin concentrations were signi®cantly higher in pregnant women when compared to non-pregnant women. Our study further indicated that this pregnancyrelated increase in leptin concentration starts within the ®rst 2 ± 3 weeks after conception.…”

“…Serum leptin concentrations are strongly associated to body fatness in adults, children and infants Clapp & Kiess, 1998;Considine et al, 1996;Ellis & Nicolson, 1997;Marchini et al, 1998). During pregnancy, a marked increase in the maternal serum leptin concentration occurs, which is followed by a sharp decrease immediately after delivery (Butte et al, 1997;Hardie et al, 1997;Sattar et al, 1998;Schrubing et al, 1998). Several studies have demonstrated that, aside from adipose tissue, the human placenta also synthesizes leptin (Masuzaki et al, 1997;Sen Äaris et al, 1997).…”

Leptin as a marker of sexual dimorphism in newborn infants

“…Enquanto a leptina proveniente do líquido amniótico reflete o ambiente materno, a leptina do cordão é derivada tanto da placenta como do tecido fetal. Assim, a maioria dos estudos publicados até o momento são unâni-mes ao afirmar que a leptina dosada no sangue materno se correlaciona apenas com a adiposidade maternal [12][13][14] .…”

Modulation of susceptibility to weight gain and insulin resistance in low birthweight rats by treatment of their mothers with leptin during pregnancy and lactation

“…Circulating leptin levels rise during pregnancy in humans and, according to some studies, in rats. 13,14 Associated with this rise is the increased expression of leptin mRNA in the placenta in humans 15 and, according to some 14 although not all 16 studies, in rats. Whether the rise in circulating leptin levels is due to increased production in the placenta or adipose tissue, or to increased production of a binding protein that inhibits leptin metabolism is unclear.…”