Leptin in first trimester pregnancy serum: no reduction associated with small-for-gestational-age infants

Maternal and fetal serum leptin levels and their association with maternal and fetal variables and labor: A cross-sectional study

Background

Leptin is a polypeptide hormone that may be implicated in the pathogenesis of various disorders during pregnancy. We sought to determine serum leptin levels among pregnant women and their fetuses and to investigate their association with fetal and maternal variables.

Method

452 pregnant women who attended to labor ward between January 2020 and August 2020 were included in the study. Serum leptin concentrations were measured using enzyme-linked immunosorbent assay method. Mann-Whitney U test and Spearman's correlation test were used for statistical analysis. A multivariate linear regression analysis was then performed. Significance level was considered at alpha <0.05.

Results

The median maternal and fetal serum leptin levels were 6.42 [4.16-8.51] ng/mL and 2.9 [1.03-5.36] ng/mL respectively. There was no significant correlation between maternal and fetal serum leptin levels (p = 0.064). Maternal serum leptin levels correlated positively with maternal body mass index (BMI) (r = 0.117, p = 0.005). Besides, maternal serum leptin levels were significantly higher in nulliparous women (7.57 [4.45-9.30] ng/mL vs. 6.22 [4.02-8.30] ng/mL, p = 0.037) and in women who were in active labor (6.83 [4.39-8.92] ng/mL vs. 6.25 [4.04-8.30] ng/mL, p = 0.047). Fetal serum leptin levels were significantly higher in large for gestational age (LGA) fetuses (4.81 [2.13-7.22] ng/mL vs. 2.80 [0.96-5.16] ng/mL, p = 0.003) and in fetuses with preterm premature ruptures of membranes (PPROM) (5.23 [2.42-8.07] ng/mL vs. 2.86 [1.00-5.23] ng/mL, p = 0.021).

Conclusion

Maternal serum leptin levels were influenced by maternal BMI, parity and labor. Fetal serum leptin levels were higher among LGA fetuses and in fetuses with PPROM.

First-trimester irisin and fetuin-A concentration in predicting macrosomia

Objective: We investigated the diagnostic value of first-trimester adipokines and placental markers in predicting macrosomia. Methods: Out of 328 women recruited during the prenatal diagnosis between 11th and 13th week of pregnancy and subjected to follow up until delivery, we selected 26 women who gave birth to macrosomic babies and 34 women who gave birth to normal weight neonates for the evaluation of first trimester serum levels of pregnancy associated plasma protein-A, free β-human chorionic gonadotropin, placental growth factor (PIGF), and selected adipokines. Results: The mothers of macrosomic infants had higher PIGF (p = .049) and irisin concentrations (p = .00003), and lower fetuin-A levels (p = .0002) than had the mothers of normal weight babies. Newborn's weight correlated positively with maternal irisin (R = 0.454, p = .0003) and negatively with fetuin-A concentrations (R = -0.497, p = .00005). Multiple regression analysis showed that only serum irisin concentration was a significant predictor of birth weight (β = 0.329, p = .03), explaining 14% of its variability. The sensitivity and the specificity of irisin concentration in predicting macrosomia were 0.769 and 0.794, respectively (AUC = 0.818 [95%CI: 0.708-0.928], p = .00001) with a proposed cut-off value of 1725.4 ng/ml. Conclusions: Our results suggest that mother's irisin may be an early biomarker of macrosomia.

Blood-based biomarkers of adverse perinatal outcomes in maternal obesity

OBJECTIVE

Increasing maternal weight has been shown to predict adverse perinatal outcome, including increases in the relative risk of fetal death, stillbirth, neonatal death, perinatal death and infant death. In order to better understand the pathophysiological factors associated with obesity during pregnancy, the role of biomarkers associated with adverse outcomes in obese pregnant women is under investigation. The purpose of this review study was to examine potential biomarkers that could serve as effective screening strategies in obese pregnant women to reduce fetal and neonatal morbidity, as well as maternal morbidity.

METHODS

Electronic databases (Pubmed, Embase) were searched for previously published research studies that investigated biomarkers associated with perinatal outcomes in obese pregnant women and the putative mechanisms underlying biomarker effects on pregnancy outcomes.

RESULTS

It is evident that while several biomarkers predict perinatal complications in obese pregnant women, none fulfilled the criteria to be considered clinically useful.

CONCLUSION

There is a critical need for reliable blood-based biomarkers associated with an increased risk of adverse perinatal outcomes in obese pregnant women.

Hyperleptinemia During Pregnancy Decreases Adult Weight of Offspring and Is Associated With Increased Offspring Locomotor Activity in Mice

Pregnant women who are obese or have gestational diabetes mellitus have elevated leptin levels and their children have an increased risk for child and adult obesity. The goals of this study were to determine whether offspring weights are altered by maternal hyperleptinemia, and whether this occurs via behavioral changes that influence energy balance. We used 2 hyperleptinemic mouse models. The first was females heterozygous for a leptin receptor mutation (DB/+), which were severely hyperleptinemic, and that were compared with wild-type females. The second model was wild-type females infused with leptin (LEP), which were moderately hyperleptinemic, and were compared with wild-type females infused with saline (SAL). Total food consumption, food preference, locomotor activity, coordinated motor skills, and anxiety-like behaviors were assessed in wild-type offspring from each maternal group at 3 postnatal ages: 4-6, 11-13, and 19-21 weeks. Half the offspring from each group were then placed on a high-fat diet, and behaviors were reassessed. Adult offspring from both groups of hyperleptinemic dams weighed less than their respective controls beginning at 23 weeks of age, independent of diet or sex. Weight differences were not explained by food consumption or preference, because female offspring from hyperleptinemic dams tended to consume more food and had reduced preference for palatable, high-fat and sugar, food compared with controls. Offspring from DB/+ dams were more active than offspring of controls, as were female offspring of LEP dams. Maternal hyperleptinemia during pregnancy did not predispose offspring to obesity, and in fact, reduced weight gain.

Maternal psychiatric disease and epigenetic evidence suggest a common biology for poor fetal growth

BACKGROUND

We sought to identify and characterize predictors of poor fetal growth among variables extracted from perinatal medical records to gain insight into potential etiologic mechanisms. In this process we reevaluated a previously observed association between poor fetal growth and maternal psychiatric disease.

METHODS

We evaluated 449 deliveries of >36 weeks gestation that occurred between 9/2008 and 9/2010 at the Women and Infants Hospital in Providence Rhode Island. This study group was oversampled for Small-for-Gestational-Age (SGA) infants and excluded Large-for-Gestational-Age (LGA) infants. We assessed the associations between recorded clinical variables and impaired fetal growth: SGA or Intrauterine Growth Restriction (IUGR) diagnosis. After validating the previously observed association between maternal psychiatric disease and impaired fetal growth we addressed weaknesses in the prior studies by explicitly considering antidepressant use and the timing of symptoms with respect to pregnancy. We then evaluated DNA methylation levels at 27 candidate loci in placenta from a subset of these deliveries (n = 197) to examine if epigenetic variation could provide insight into the mechanisms that cause this co-morbidity.

RESULTS

Infants of mothers with prenatal psychiatric disease (Depression, Anxiety, OCD/Panic) had increased odds of poor fetal growth (ORadjusted = 3.36, 95%CI: 1.38-8.14). This relationship was similar among those who were treated with antidepressants (ORadjusted = 3.69, 95%CI: 1.31-10.45) and among those who were not (ORadjusted = 3.19, 95%CI: 1.30-7.83). Among those with a history of psychiatric disease but no active disease in pregnancy the ORadjusted was 0.45 (95%CI: 0.09-2.35). A locus near the transcription start site of the leptin receptor (cg21655790) had methylation levels that were decreased in the presence of: 1) SGA/IUGR, and 2) active but not resolved psychiatric disease (among mothers not on antidepressants).

CONCLUSIONS

These results validate and further characterize the association between maternal psychiatric disease and poor fetal growth. Because the association appears to depend on active psychiatric disease, this suggests a transient and potentially modifiable pathophysiology. The molecular findings in this study suggest that altered leptin signaling may be involved in the biological mechanisms that link prenatal maternal psychiatric symptoms and poor fetal growth.

Mid-pregnancy maternal leptin levels, birthweight for gestational age and preterm delivery

OBJECTIVE

Maternal blood leptin levels are positively associated with adiposity. Recent studies suggest that leptin is also abundantly produced by the placenta and may function as a regulator of foetal growth. Our goal was to examine mid-pregnancy levels of leptin in maternal blood in relation to birthweight for gestational age (BW/GA) and timing of delivery after accounting for maternal prepregnancy body mass index (prepreg-BMI) and pregnancy complications.

PATIENTS

Data were from 1304 subcohort mother/infant pairs who participated in the Pregnancy Outcomes and Community Health (POUCH) Study (1998-2004).

MEASUREMENTS

Leptin levels, measured at 16-27 weeks' gestation, were log-transformed. Geometric mean (GMean) leptin levels were estimated by weighted linear regression with gestational age at blood draw as a covariate. GMean was re-transformed to the original scale for reporting.

RESULTS

Using the GMeans leptin in mothers of term appropriate-for-gestational age (AGA) neonates as the referent (25·2 μg/l), we observed lower levels in mothers of preterm-AGA (21·9 μg/l), term small-for-gestational age (SGA) (20·3 μg/l) and preterm-SGA neonates (21·7 μg/l). Results were largely unchanged after adjustment for prepreg-BMI. Leptin levels were higher in mothers who delivered large-for-gestational age (LGA) neonates, both preterm (33·6 μg/l) and term (29·1 μg/l), but the GMeans were markedly attenuated after adjustment for prepreg-BMI.

CONCLUSION

The association between BW/GA and maternal leptin levels after adjustment for prepreg-BMI may represent: (i) a residual effect of maternal adiposity that is not fully captured by BMI; and/or (ii) variation in placental leptin levels entering the maternal circulation. In conclusion, mid-pregnancy maternal blood leptin levels may be an early indicator of foetal growth status.

Effect of food restriction and leptin supplementation on fetal programming in mice

Metabolic disease is a significant global health and economic problem. In a phenomenon referred to as fetal programming, offspring of underweight or overweight mothers have an increased incidence of adulthood obesity and metabolic disease. Undernourished individuals have decreased levels of leptin, a regulator of energy balance, whereas obese people develop hyperleptinemia and leptin resistance. We hypothesize that alterations in circulating leptin during pregnancy contribute to programming events caused by maternal nutritional status. To test this hypothesis, pregnant mice were randomly placed in one of three treatment groups: ad libitum feed plus saline injection (control, n = 5), 50% food restriction plus saline injection (restricted, n = 4), or 50% food restriction plus 1 mg/kg · d leptin injection (restricted, leptin treated, n = 4). Mice were treated from 1.5 to 11.5 d after conception and then returned to ad libitum feeding until weaning. At 19 wk after weaning, offspring were placed on a 45% fat diet and then followed up until 26 wk after weaning, at which time they were killed, and samples were collected for further analysis. Our results demonstrate that males are more negatively impacted by high-fat diet than females, regardless of maternal treatment. We provide evidence that differential response to leptin may mediate the sexual dimorphism observed in fetal programming in which male offspring are more affected by maternal undernutrition and female offspring by maternal overnutrition. We show that female offspring born to food-restricted, leptin-supplemented mothers are obese and insulin resistant. This may mimic fetal programming events seen in offspring of overweight women.