The differential effects of body fat distribution on insulin and glucose metabolism during pregnancy

Identification of key metabolism-related genes and pathways in spontaneous preterm birth: combining bioinformatic analysis and machine learning

Background

Spontaneous preterm birth (sPTB) is a global disease that is a leading cause of death in neonates and children younger than 5 years of age. However, the etiology of sPTB remains poorly understood. Recent evidence has shown a strong association between metabolic disorders and sPTB. To determine the metabolic alterations in sPTB patients, we used various bioinformatics methods to analyze the abnormal changes in metabolic pathways in the preterm placenta via existing datasets.

Methods

In this study, we integrated two datasets (GSE203507 and GSE174415) from the NCBI GEO database for the following analysis. We utilized the "Deseq2" R package and WGCNA for differentially expressed genes (DEGs) analysis; the identified DEGs were subsequently compared with metabolism-related genes. To identify the altered metabolism-related pathways and hub genes in sPTB patients, we performed multiple functional enrichment analysis and applied three machine learning algorithms, LASSO, SVM-RFE, and RF, with the hub genes that were verified by immunohistochemistry. Additionally, we conducted single-sample gene set enrichment analysis to assess immune infiltration in the placenta.

Results

We identified 228 sPTB-related DEGs that were enriched in pathways such as arachidonic acid and glutathione metabolism. A total of 3 metabolism-related hub genes, namely, ANPEP, CKMT1B, and PLA2G4A, were identified and validated in external datasets and experiments. A nomogram model was developed and evaluated with 3 hub genes; the model could reliably distinguish sPTB patients and term labor patients with an area under the curve (AUC) > 0.75 for both the training and validation sets. Immune infiltration analysis revealed immune dysregulation in sPTB patients.

Conclusion

Three potential hub genes that influence the occurrence of sPTB through shadow participation in placental metabolism were identified; these results provide a new perspective for the development and targeting of treatments for sPTB.

Avoiding excessive pregnancy weight gain to obtain better pregnancy outcomes in Taiwan

Pregnancy weight gain may be associated with adverse pregnancy outcomes. The article aims to explore the relationship between weight change and pregnancy outcome in the Taiwanese pregnant women.The retrospective cohort study enrolled women with vertex singleton pregnancy at University-associated Hospital between 2011 and 2014. Pregnancy weight change was separated into 3 groups, based on the Institute of Medicine (IOM) guidelines: below (n = 221); within (n = 544); and above (n = 382). Analysis of variance, χ tests, generalized linear models, and logistic regression models were used for statistical comparisons.Pregnant women with weight change above IOM guidelines had a significant increase in both maternal and perinatal complications compared with normal controls (odds ratio [OR] 1.65, 95% confidence interval [CI] 1.03-1.98; P = .043; OR 1.45, 95% CI 1.01-1.87; P = .049, respectively). This finding was not found in pregnant women with weight gain below IOM guidelines. Moreover, age (OR 1.08, 95% CI 1.02-1.15; P = .0011), pre-pregnancy weight (OR 1.04, 95% CI 1.01-1.09; P = .0008), pre-pregnancy body mass index (BMI; OR 1.15, 95% CI 1.06-1.30; P < .0001), weight at the time of delivery (OR 1.05, 95% CI 1.02-1.13; P < .0001) and BMI at the time of delivery (OR 1.15, 95% CI 1.06-1.39; P < .0001), all contributed to increased maternal complications but not perinatal complications, whereas parity (OR 0.23, 95% CI 0.12-0.41; P < .0001) and gestational age (OR 0.50, 95% CI 0.35-0.62; P < .001) were associated with fewer maternal complications.Our study reconfirmed that for Taiwanese pregnant women, the approximate pregnancy weight gain recommended by IOM in 2009 was associated with the fewest maternal and perinatal complications. If approximate pregnancy weight gain cannot be attained, even less weight gain during pregnancy is still reasonable without significantly and adversely affecting maternal and perinatal outcomes in Taiwan.

Prepregnancy body size, gestational weight gain, and risk of preterm birth in African-American women

BACKGROUND

Studies of the association of prepregnancy body mass index (BMI) and preterm birth have been inconclusive, and no studies have examined the effect of central adiposity on risk. There is also uncertainty about optimal gestational weight gain among Black women.

METHODS

Using self-reported prospective data from the Black Women's Health Study, we investigated the relation of preterm birth to prepregnancy BMI (kg/m), waist circumference, and gestational weight gain among 7840 singletons born to black women, ages 21-44, during 1995-2003. We compared mothers of 1114 infants born 3 or more weeks early (597 spontaneous preterm births and 517 medically-indicated preterm births) with mothers of 6726 term infants. We used generalized estimating equation models to derive multivariable odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Relative to normal weight women (BMI: 18.5-24.9), underweight women (BMI: <18.5) were at increased risk of both preterm birth subtypes; obese women (BMI > or = 30.0) were at increased risk of medically-indicated preterm birth and very early spontaneous preterm birth (<32 weeks' gestation). Waist circumference, a measure of central adiposity, was positively associated with medically-indicated preterm birth. Among obese women, average gestational weight gain in the second and third trimesters of <0.4 or >0.6 lbs/wk was associated with an increased risk of both preterm birth subtypes.

CONCLUSIONS

Our data suggest that underweight increases risk of both preterm birth subtypes, while obesity increases risk of medically-indicated preterm birth and only a subgroup of spontaneous preterm births (<32 weeks' gestation). Central adiposity was an independent risk factor for medically-indicated preterm birth only. Among obese women, gestational weight gain within the range recommended by the 2009 Institute of Medicine report (0.4-0.6 lbs/week in the second and third trimesters) was associated with the lowest risk of preterm birth.

Review: Diabetes in pregnancy: insulin resistance, obesity and placental dysfunction

Obesity in pregnancy is linked to increased morbidity and mortality for mother and baby. The incidence of gestational diabetes is increased approximately two to six-fold in women who are overweight-obese and the presence of diabetes is a further metabolic challenge which is associated with adverse outcomes. Herein the role of obesity is discussed in the generation of insulin resistance and inflammation and its contribution to placental dysfunction.

Weight retention within the puerperium in adolescents: a risk factor for obesity?

OBJECTIVE

The present study aimed to investigate weight retention and body composition in the postpartum period between adolescent girls and older women.

DESIGN

A prospective cohort study. Anthropometry and skinfold thickness measurements were performed at the first antenatal visit and at 6 weeks postpartum. An FFQ was administered at 6 weeks postpartum to explore the relationship between diet and postpartum weight retention.

SETTING

Clinics at the University of the West Indies, Kingston, Jamaica.

SUBJECTS

Recruitment included women aged 19 years and younger (adolescent girls) and 20 years and older (older women).

RESULTS

Three hundred and forty women were studied. Adolescent girls had significantly lower measurements compared with the older women at the first antenatal visit and at 6 weeks postpartum. Dietary intakes of energy and macronutrients were similar in both groups. Postnatal assessments showed that adolescent girls retained more weight (P = 0.003) and a greater percentage of body fat (P < 0.002) than older women. In multiple regression analyses, 0.982 kg more fat mass was retained postpartum in the adolescent group compared with the older women, while there was no significant difference in lean body mass retained between the two groups.

CONCLUSIONS

Adolescent girls retained more weight postpartum and this was predominantly fat mass as opposed to lean body mass.

Maternal obesity, metabolism, and pregnancy outcomes

About one third of all pregnant women in the United States are obese. Maternal obesity at conception alters gestational metabolic adjustments and affects placental, embryonic, and fetal growth and development. Neural tube defects and other developmental anomalies are more common in infants born to obese women; these defects have been linked to poor glycemic control. Preeclampsia, a gestational disorder occurring more frequently in obese women, appears to be due to a subclinical inflammatory state that impairs early placentation and development of its blood supply. Fetal growth and development during the last half of pregnancy depends on maternal metabolic adjustments dictated by placental hormones and the subsequent oxygen and nutrient supply. Maternal obesity affects these metabolic adjustments as well. Basal metabolic rates are significantly higher in obese women, and maternal fat gain is lower, possibly in response to altered leptin function. The usual increase in insulin resistance seen in late pregnancy is enhanced in obese mothers, causing marked postprandial increases in glucose, lipids, and amino acids and excessive fetal exposure to fuel sources, which in turn increases fetal size, fat stores, and risk for disease postnatally. Impaired glucose tolerance, gestational diabetes, and hyperlipidemia are more common among obese mothers. To date, little attention has been given to the role of diet among obese women in preventing these problems. However, studies of women with impaired glucose tolerance show that replacing refined carbohydrates and saturated fat with complex, low-glycemic carbohydrates and polyunsaturated fatty acids improves metabolic homeostasis and pregnancy outcomes. Thus, current dietary guidelines regarding the amount and type of carbohydrates and fat for nonpregnant women seem appropriate for pregnant women as well.

Mild gestational hyperglycemia, the metabolic syndrome and adverse neonatal outcomes

BACKGROUND

The aim of this study was to evaluate the prevalence of the metabolic syndrome and its effect on neonatal outcomes in pregnancies with different degrees of hyperglycemia.

METHODS

One hundred and fifty women with gestational diabetes, 100 with one abnormal value on the oral glucose tolerance test, 100 with a normal oral glucose challenge test and 350 with an abnormal challenge test and normal tolerance test were enrolled.

RESULTS

The prevalence of the metabolic syndrome was: 0%, 4.9%, 20% and 18% in the normal challenge test, abnormal challenge and normal tolerance test, one abnormal value and gestational diabetes patients, respectively. Offspring birth weights, prevalence of large-for-gestational age babies and icterus were significantly higher in women with an abnormal challenge test (both with a normal tolerance test or one abnormal value or gestational diabetes). Metabolic syndrome was the best predictor of the presence of large-for-gestational age babies in patients with an abnormal challenge and normal tolerance test (OR = 3.15), one abnormal value (OR = 3.53) and gestational diabetes (OR = 4.15).

CONCLUSIONS

Metabolic syndrome in mid-pregnancy was an independent predictor of macrosomia in women with any degree of gestational hyperglycemia; the oral glucose challenge test identifies pregnancies with metabolic abnormalities and adverse neonatal outcomes also in the presence of a normal oral glucose tolerance test.

Does incomplete growth and development predispose teenagers to preterm delivery? A template for research

Pregnant teenagers are in better physical condition, suffer from fewer chronic diseases, and engage in fewer health-risky behaviors than socioeconomically similar pregnant adults, but give birth to a disproportionately large number of preterm infants. This systematic review of the adolescent pregnancy literature defines the unique risks associated with being young and pregnant by examining how the physical and psychosocial changes that are characteristic of puberty and adolescence interact with traditional risk factors for preterm delivery. The need for age-specific interventions is discussed and recommendations for future research are made.

Obesity and pregnancy: complications and cost

The prevalence of obesity is currently rising in developed countries, making pregravid overweight one of the most common high-risk obstetric situations. Although the designs and populations of published studies vary widely, most authors agree that pregravid overweight increases maternal and fetal morbidity. Even moderate overweight is a risk factor for gestational diabetes and hypertensive disorders of pregnancy, and the risk is higher in subjects with overt obesity. Compared with normal weight, maternal overweight is related to a higher risk of cesarean deliveries and a higher incidence of anesthetic and postoperative complications in these deliveries. Low Apgar scores, macrosomia, and neural tube defects are more frequent in infants of obese mothers than in infants of normal-weight mothers. The regional distribution of fat modulates the effects of weight on carbohydrate tolerance, hemodynamic adaptation, and fetal size. Maternal obesity increases perinatal mortality. Long-term complications include worsening of maternal obesity and development of obesity in the infant. The average cost of hospital prenatal and postnatal care is higher for overweight mothers than for normal-weight mothers, and infants of overweight mothers require admission to neonatal intensive care units more often than do infants of normal-weight mothers. Preconception counseling, careful prenatal management, tight monitoring of weight gain, and long-term follow-up could minimize the social and economic consequences of pregnancies in overweight women.

Maternal obesity and glucose intolerance during pregnancy among Mexican-Americans

Low birthweight is uncommon among Mexican-American infants, despite the substantial proportion of mothers who live in poverty. This apparent paradox has generated studies of factors protecting fetal growth, but may have masked other important health problems in the Mexican-American community. Obesity, impaired glucose tolerance and diabetes are common among Mexican-American women of childbearing age and during pregnancy. Prevalence of these conditions is two to four times higher in Mexican-American than in non-Hispanic white women. As obesity and glucose intolerance during pregnancy are associated with fetal overgrowth and increased risk of subsequent obesity and type 2 diabetes in mother and child, the adequacy of birthweight as a measure of maternal and infant risk may be obscured in populations with a high prevalence of these conditions. Their possible contribution to the increasing incidence of obesity and type 2 diabetes in Mexican-American children, adolescents and young adults has not been examined. Appropriate preconception, prenatal and follow-up care may identify high-risk women, improve weight and metabolic status and reduce the severity and impact of diabetes and its complications. However, late or no prenatal care is common among Mexican-American women and the frequency of follow-up care is unknown. As low birthweight is a major public health indicator of maternal and neonatal health, perceived 'good birth outcomes' have reduced health policy, programme and research attention to Mexican-American mothers and infants. Studies of the impact of obesity and glucose intolerance during pregnancy on the birthweights of Mexican-American infants should be undertaken, along with systematic assessment of the subsequent health status and preventive health-care needs of women and children in this population.

When is fasting really fasting? The influence of time of day, interval after a meal, and maternal body mass on maternal glycemia in gestational diabetes

OBJECTIVE

The object of the study was to determine whether time of day, interval after a standard meal, and maternal body mass influence plasma glucose concentrations in women with gestational diabetes mellitus.

STUDY DESIGN

Identical mixed meals were administered on 2 separate occasions 1 week apart to 30 women with dietarily treated gestational diabetes and pregnancies between 28 and 38 weeks' gestation. One meal was administered at 7 AM (morning meal) and the other was administered at 9 PM (evening meal), each after a fast of >/=5 hours. The order of the meals (morning first versus evening first) was assigned randomly. Sixteen of the women had a body mass index >/=27 kg/m(2) (overweight) and 14 women had a body mass index <27 kg/m(2) (lean). Venous plasma concentrations of glucose, insulin, free fatty acids, beta-hydroxybutyrate, and bound and free cortisol were measured hourly for 9 hours after each of the test meals.

RESULTS

When all women were considered together glucose concentrations after the morning meal were significantly greater at 1 hour, were not different at 2 hours, and were significantly lower from 3 through 9 hours postprandially than those at corresponding times after the evening meal. Plasma beta-hydroxybutyrate and free fatty acid concentrations were higher between 5 and 9 hours after the morning meal than at the same times after the evening meal. Total and free cortisol levels were higher for the first 7 hours after the morning feeding, reflecting known diurnal variation in cortisol concentrations. Overweight patients' glucose values were significantly greater than those of lean subjects during the last 4 hours of the overnight fast.

CONCLUSIONS

Among women with dietarily treated gestational diabetes the glucose concentrations were significantly higher from 3 to 9 hours after an evening meal, whereas suppression of free fatty acids and beta-hydroxybutyrate was less sustained after a morning feeding. The mechanisms underlying these differences remain to be determined but may involve diurnal influences of counterregulatory hormones. The relationships between measurements of maternal glycemia and maternal and perinatal outcomes in pregnancies complicated by gestational diabetes may be clarified by establishing a uniform duration of a fast and by developing meal-specific preprandial and postprandial maternal glucose targets for these patients.

Observational study of maternal anthropometry and fetal insulin

AIMS

To examine the relation between maternal body fat and fetal metabolism.

METHODS

In this observational study, cord blood samples were collected from 60 infants of healthy women for the measurement of insulin and C peptide concentrations. Maternal weight, height, body mass index (BMI) and body composition (skinfold thickness measurements and bioelectrical impedance) were assessed at 13-15 weeks of gestation. Twenty five of the volunteers agreed to have a 75 g oral glucose tolerance test at 28-31 weeks of gestation.

RESULTS

Positive correlations were observed with both cord insulin or C peptide concentrations and maternal early pregnancy BMI (r=0.44, p=0.002 and r=0.33, p=0.008, respectively). There was no significant correlation between cord insulin or C peptide concentrations and birthweight or birth weight centiles.

CONCLUSION

Maternal BMI could be a predictor of fetal cord insulin concentration.

History of gestational diabetes, insulin resistance and coronary risk

The purpose of this study was to examine characteristics associated with the insulin metabolic syndrome, including insulin resistance, abnormal glucose tolerance, dyslipidemia, obesity, and elevated blood pressure, among women who have experienced gestational diabetes. 39 nondiabetic, young (20-42 years), postpartum (3-18 months) white women were recruited from obstetrical clinics. Twenty-one women had a history of gestational diabetes; 18 had uncomplicated pregnancies. Multivariate analyses revealed a significant difference between groups in insulin resistance (M, measured by euglycemic clamp) and insulin levels (from an oral glucose tolerance test), with insulin resistance showing a statistically stronger difference than insulin levels. Groups also differed significantly when compared on a set of variables associated with insulin metabolic syndrome: glucose tolerance, triglycerides, blood pressure, and body-mass index. Using insulin resistance as a covariate eliminated these group differences, suggesting that insulin resistance is the key factor underlying insulin metabolic syndrome. The higher risk of later developing type 2 diabetes and hypertension in women who have a history of gestational diabetes is explicable by their poorer profile on variables associated with insulin metabolic syndrome, and appears to be attributable to insulin resistance. Thus, insulin resistance appears to distinguish young women at risk for cardiovascular disease.

Perinatal outcomes of obese women: a review of the literature

OBJECTIVE

To review the literature addressing the effect of obesity on pregnancy outcomes and to identify practice and research implications.

DATA SOURCES

Computerized searches in Medline and CINAHL, as well as references cited in articles reviewed. Key words used in the search were as follows: pregnancy and obesity; pregnancy complications; weight gain and pregnancy; weight gain and complications; fat distribution and pregnancy and complications; and obstetrics and obesity.

STUDY SELECTION

Articles and comprehensive works from indexed journals in the English language relevant to key words and published after 1978 were evaluated.

DATA EXTRACTION

Data were extracted and organized under the following headings: methodologic issues; physiologic adjustments; antepartum, intrapartum, postpartum and newborn outcomes; and cost.

DATA SYNTHESIS

Obese pregnant women experience more gestational diabetes, neural tube defects, preeclampsia, induction, primary cesarean, and postpartum infection than pregnant women who are not obese.

CONCLUSIONS

Pregnant women who are obese are at increased risk for certain complications during pregnancy, birth, and postpartum. Little is known about the effect that fat distribution (upper versus lower, which is influential in nonpregnant populations) has on obstetric complications. Even less is known about obese pregnant women's perceptions of risk, changes in lifestyle, functioning, health behaviors, and symptoms experienced during pregnancy.