Adjustments in energy expenditure and substrate utilization during late pregnancy and lactation

Association between breastfeeding duration and diabetes mellitus in menopausal women: a machine-learning analysis using population-based retrospective study

BACKGROUND

Breastfeeding resets insulin resistance caused by pregnancy however, studies on the association between breastfeeding and diabetes mellitus (DM) have reported inconsistent results. Therefore, we aimed to investigate the risk of DM according to breastfeeding duration in large-scale population-based retrospective study. In addition, machine-learning prediction models for DM and hemoglobin A1c (HbA1c) were developed to further evaluate this association.

METHODS

We used the Korean National Health and Nutrition Examination Surveys database, a nationwide and population-based health survey from 2010 to 2020. We included 15,946 postmenopausal women with a history of delivery, whom we divided into three groups according to the average breastfeeding duration: (1) no breastfeeding, (2) < 12 months breastfeeding, and (3) ≥ 12 months breastfeeding. Prediction models for DM and HbA1c were developed using an artificial neural network, decision tree, logistic regression, Naïve Bayes, random forest, and support vector machine.

RESULTS

In total, 2248 (14.1%) women had DM and 14,402 (90.3%) had a history of breastfeeding. The prevalence of DM was the lowest in the < 12 breastfeeding group (no breastfeeding vs. < 12 months breastfeeding vs. ≥ 12 months breastfeeding; 161 [10.4%] vs. 362 [9.0%] vs. 1,725 [16.7%], p < 0.001). HbA1c levels were also the lowest in the < 12 breastfeeding group (HbA1c: no breastfeeding vs. < 12 months breastfeeding vs. ≥ 12 months breastfeeding; 5.9% vs. 5.9% vs. 6.1%, respectively, p < 0.001). After adjustment for covariates, the risk of DM was significantly increased in both, the no breastfeeding (adjusted odds ratio [aOR] 1.29; 95% CI 1.29, 1.62]) and ≥ 12 months of breastfeeding groups (aOR 1.18; 95% CI 1.01, 1.37) compared to that in the < 12 months breastfeeding group. The accuracy and the area under the receiver-operating-characteristic curve of the DM prediction model were 0.93 and 0.95, respectively. The average breastfeeding duration was ranked among the top 15 determinants of DM, which supported the strong association between breastfeeding duration and DM. This association was also observed in a prediction model for HbA1c.

CONCLUSIONS

Women who did not breasted had a higher risk of developing DM than those who breastfed for up to 12 months.

Breastfeeding is associated with a delayed decrease in postprandial maternal glucose concentration

BACKGROUND

Breastfeeding has long-term benefits in reducing the risk of diabetes; however, information about the acute influence on maternal glucose profile is scarce. Thus, the aim of the study was to assess maternal glucose fluctuations associated with breastfeeding episodes in women with normal glucose status.

METHODS

We performed an observational study of glucose fluctuations with breastfeeding episodes in 26 women with normal glucose status in fasting and postprandial state. Continuous glucose monitoring was performed using CGMS MiniMed Gold®/iPro2® (Medtronic, Dublin, Ireland) three months after delivery under real-life conditions. We compared fasting and postprandial periods of 150 minutes affected or not by a breastfeeding episode.

RESULTS

Mean glucose concentration of postprandial periods affected by breastfeeding was lower than not affected (-6.31 mg/dL [95% CI: -11.17, -1.62] P<0.01). Glucose concentration was significantly lower between 50 and 105 minutes after meal initiation (maximum difference -9.19 mg/dL [95% CI: -16.03, -2.16] at 91-95 min). Mean glucose concentrations of fasting periods affected by breastfeeding were similar to those not affected (-0.18 mg/dL [95% CI: -2.7, 0] P=0.831).

CONCLUSIONS

In women with normal glucose status, breastfeeding episodes are associated with a lower glucose concentration in the postprandial but not in the fasting state.

The Effects of Breastfeeding and Gestational Diabetes Mellitus on Body Mass Composition and the Levels of Selected Hormones after Childbirth

Breastfeeding may have a positive effect on glucose metabolism and insulin sensitivity, which may reduce the risk of developing diabetes following gestational diabetes mellitus (GDM). This study aimed to evaluate the effect of breastfeeding and GDM on the body mass composition of the studied women, the levels of leptin, ghrelin, adiponectin, resistin, and insulin, and weight loss during the 6-8-week postpartum period and 1 year after childbirth.

MATERIALS AND METHODS

The study group included 42 women with a singleton pregnancy, diagnosed with GDM between the 24th and 28th week of gestation. The control group consisted of 28 non-diabetic women with a singleton pregnancy. This study was carried out at 6-8 weeks as well as at 1 year postpartum. The women were subjected to body weight measurements and body composition analysis performed using a professional body composition analyzer TANITA DC-430 S MA. Waist circumference and subcutaneous fat was measured. Blood for laboratory tests was taken in the morning, on an empty stomach.

RESULTS

It was shown that, regardless of diabetes, exclusive breastfeeding had a significant impact on weight loss at 6-8 weeks postpartum (p = 0.014785) and lower insulin levels (p = 0.047). However, there was no effect of breastfeeding on the women's anthropometric measurements or hormone levels one year after delivery, except for the thickness of subcutaneous adipose tissue, which was significantly lower in breastfeeding women (p = 0.03). One year after delivery, breastfeeding women had a lower BMI (p = 0.0014), less-thick subcutaneous adipose tissue (p < 0.001), and a lower risk of obesity (p = 0.016). There were also higher insulin and ghrelin levels in both breastfeeding and non-breastfeeding women (p < 0.001), and lower resistin levels in non-breastfeeding women (p = 0.004). Women who had diabetes during pregnancy had a significantly reduced waist circumference and subcutaneous fat thickness after one year (p < 0.001 and p = 0.05, respectively).

CONCLUSIONS

Having diabetes during pregnancy did not significantly affect the results of anthropometric measurements and hormone levels noted at 6-8 weeks after delivery (the only exception was the thickness of subcutaneous fat tissue, which was greater in women without GDM). This may indicate normalization of carbohydrate metabolism after childbirth; however, the observation period is too short to elucidate long-term metabolic effects. This suggests the need for further research related to GDM and breastfeeding.

Take it to the limit: The limitations of energetic explanations for birth timing in humans

A hallmark of modern humans is that our newborns are neurologically immature compared to other primates. It is disputed whether this so-called secondary altriciality evolved due to remodelling of the pelvis associated with bipedal locomotion, as suggested by the obstetrical dilemma hypothesis, or from maternal energetic limitations during pregnancy. Specifically, the 'Energetics of Gestation and Growth' (EGG) hypothesis posits that birth is initiated when foetal energy requirements exceed the maximum sustained maternal metabolic rate during pregnancy at around 2.1 × basal metabolic rate (BMR) of the non-pregnant, non-lactating condition (NPNL). However, the metabolic threshold argued under the EGG framework is derived from one study with a small sample size of only 12 women from the UK. Accordingly, we performed a meta-analysis of all published studies on metabolic scopes during pregnancy to better account for variability. After excluding 3 studies with methodological issues, a total of 12 studies with 303 women from 5 high- and 3 low-income countries were analysed. On average, pregnancy was found to be less metabolically challenging than previously suggested. The studies revealed substantial variation in metabolic scope during pregnancy, which was not reflected by variation in birth timing. Further, in a third of the studies, the metabolic rates exceeded 2.1 × BMRNPNL. Our simulation of foetal energy requirements demonstrated that this metabolic threshold of 2.1 × BMRNPNL cannot realistically be crossed by the foetus around the time of birth. These findings imply that metabolic constraints are not the main limiting factor dictating gestation length.

New frontiers in the measurement of energy metabolism

This perspective highlights three key areas of current and future energy metabolism research: intergenerational health, climate change, and interplanetary exploration. We describe the recent advances in determining estimated energy requirements for a large subset of the general population using the gold standard method for free-living total daily energy expenditure estimates, the doubly labeled water method. The global rise in overweight and obesity demands particular attention to energy requirements in pregnancy and early life, as accumulating evidence contributes to our understanding of intergenerational health transmission and the potential for epigenetic programming in utero. We also acknowledge some gaps in necessary guidelines and understandings of energy requirements for underrepresented populations (i.e., individuals from low and middle-income countries) or those who undergo major physiological changes in new environment (e.g., astronauts). The rising prevalence of excess weight gain, together with climate change, cumulate into a global syndemic exposing vulnerable populations to both malnutrition and the effects of unpredictable and severe weather events, emphasizing the need for varied energetic data accounting for rapid physiological and socioeconomic changes. Finally, we relate how specific estimated energy requirements are needed to account for the energetic challenges specific to extended space travel and ensure the success of interplanetary exploration.

Associations of Physical Activity and Lactation Duration With Cardiometabolic Risk Factors: The CARDIA Study

BACKGROUND

Physical activity (PA) and lactation benefit cardiometabolic health.

OBJECTIVES

The purpose of this study was to describe the joint associations of PA and lactation with cardiometabolic risk.

METHODS

We averaged PA across exams and summed lifetime lactation in Black and White parous women in the Coronary Artery Risk Development in Young Adults Study. Categories were created for PA (-PA:

RESULTS

The median PA was 256 exercise units and 54% reported lactation duration of ≥3 months. Of 1,068 participants, 303 were in the -PA/-L category, 231 in -PA/+L, 184 in +PA/-L, and 350 in +PA/+L. +PA/+L participants were older, had more years of education, lower body mass index, gained less weight, and less likely to be Black vs -PA/-L participants. Risk scores differed between categories except -PA/+L and +PA/-L (P = 0.08): -PA/-L: 0.23+/-0.04, -PA/+L: 0.08+/-0.04, +PA/-L: -0.02+/-0.05, and +PA/+L: -0.23+/-0.03. After adjustment, +PA/+L was associated with a lower/better risk score (β = -0.15, 95% CI: -0.25 to -0.04).

CONCLUSIONS

Above average PA throughout adulthood combined with ≥3 months of lactation was associated with lower risk scores. Participants with either behavior had lower risk vs those with neither behavior. Attaining these levels of behaviors may reduce cardiometabolic risk in parous women.

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Key Words

• cardiometabolic risk
• lactation
• physical activity

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MESH Headings Collapse

Grants

• R01 DK090047 NIDDK NIH HHS
• R01 DK106201 NIDDK NIH HHS

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Affiliation(s)

Abbi Lane Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina, USA
Kara M. Whitaker Department of Health and Human Physiology, Department of Epidemiology, University of Iowa, Iowa City, Iowa, USA
Muna Tahir ICON plc, San Francisco, California, USA
Bethany Barone Gibbs Department of Epidemiology and Biostatistics, School of Public Health, University of West Virginia, Morgantown, West Virginia, USA
Janet Catov Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA Department of Obstetrics and Gynecology, Magee-Women’s Research Center, Pittsburgh, Pennsylvania, USA
Mercedes Carnethon Department of Preventive Medicine, Feinberg School of Medicine, Chicago, Illinois, USA
Erica P. Gunderson Division of Research, Kaiser Permanente of Northern California, Oakland, California, USA

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Factors Affecting BMI Changes in Mothers during the First Year Postpartum

We tested the hypotheses that mothers of infants who exclusively breastfed would differ in the trajectories of postpartum BMI changes than mothers of infants who exclusively formula fed, but such benefits would differ based on the maternal BMI status prepregnancy (primary hypothesis) and that psychological eating behavior traits would have independent effects on postpartum BMI changes (secondary hypothesis). To these aims, linear mixed-effects models analyzed measured anthropometric data collected monthly from 0.5 month (baseline) to 1 year postpartum from two groups of mothers distinct in infant feeding modality (Lactating vs. Non-lactating). While infant feeding modality group and prepregnancy BMI status had independent effects on postpartum BMI changes, the benefits of lactation on BMI changes differed based on prepregnancy BMI. When compared to lactating women, initial rates of BMI loss were significantly slower in the non-lactating women who were with Prepregnancy Healthy Weight (β = 0.63 percent BMI change, 95% CI: 0.19, 1.06) and with Prepregnancy Overweight (β = 2.10 percent BMI change, 95% CI: 1.16, 3.03); the difference was only a trend for those in the Prepregnancy Obesity group (β = 0.60 percent BMI change, 95% CI: −0.03, 1.23). For those with Prepregnancy Overweight, a greater percentage of non-lactating mothers (47%) gained ≥ 3 BMI units by 1 year postpartum than did lactating mothers (9%; p < 0.04). Psychological eating behavior traits of higher dietary restraint, higher disinhibition, and lower susceptibility to hunger were associated with greater BMI loss. In conclusion, while there are myriad advantages to lactation, including greater initial rates of postpartum weight loss regardless of prepregnancy BMI, mothers who were with overweight prior to the pregnancy experienced substantially greater loss if they breastfed their infants. Individual differences in psychological eating behavior traits hold promise as modifiable targets for postpartum weight management.

Lactation duration and lifetime progression to metabolic syndrome in women according to their history of gestational diabetes: a prospective longitudinal community-based cohort study

BACKGROUND

Despite the many signs of progress in pharmacotherapies, metabolic syndrome (MetS) is one of the main public-health burdens worldwide. Our study aimed to compare the effect of breastfeeding (BF) in women with and without gestational diabetes mellitus (GDM) on MetS incidence.

METHODS

Of females who participated in the Tehran Lipid and glucose study, women who met our inclusion criteria were selected. The Cox proportional hazards regression model, with adjustment of potential confounders, was done to evaluate the relationship between duration of BF and incident of MetS in women with a GDM history compared to non-GDM.

RESULTS

Out of 1176 women, there were 1001 non-GDM and 175 GDM. The median follow-up was 16.3 (11.9, 19.3) years. Results of the adjusted model illustrated that the total BF duration was negatively associated with MetS incidence risk (hazard ratio (HR) 0.98, 95% CI 0.98-0.99) in total participants indicating that per one-month increase of BF duration, the hazard of MetS reduced by 2%. The HR of MetS in Comparison between GDM and non-GDM women demonstrated significantly more reduced MetS incidence with a longer duration of exclusive BF (HR 0.93, 95% CI 0.88-0.98).

CONCLUSIONS

Our findings illustrated the protective effect of BF, especially exclusive BF, on MetS incidence risk. BF is more effective in reducing the risk of MetS among women with a history of GDM than among women without such a history.

The metabolic differences of anestrus, heat, pregnancy, pseudopregnancy, and lactation in 800 female dogs

Introduction

Reproduction causes major hormonal and physiological changes to the female body. However, the metabolic changes occurring during canine reproduction are scarcely studied.

Methods

In this cross-sectional study, we assessed the metabolic effects of canine reproductive status using a ¹H NMR metabolomics platform optimized and validated for canine use. The study population consisted of a total of 837 healthy, intact female dogs in breeding age, of which 663 dogs were in anestrus, 78 in heat, 43 were pseudopregnant, 15 were pregnant, and 38 were lactating. The differences in metabolite profiles between these states were studied by the Kruskal-Wallis test with post-hoc tests performed using the Dunn's test, and visualized by box plots and a heatmap. The ability of the metabolite profile to differentiate pregnant dogs from non-pregnant ones was assessed by creating a multivariate Firth logistic regression model using forward stepwise selection.

Results

Lactation, pregnancy and heat all were associated with distinct metabolic changes; pregnancy caused major changes in the concentrations of glycoprotein acetyls, albumin and creatinine, and smaller changes in several lipids, citrate, glutamine, and alanine. Pseudopregnancy, on the other hand, metabolically largely resembled anestrus. Lactation caused major changes in amino acid concentrations and smaller changes in several lipids, albumin, citrate, creatinine, and glycoprotein acetyls. Heat, referring to proestrus and estrus, affected cholesterol and LDL metabolism, and increased HDL particle size. Albumin and glycoprotein acetyls were the metabolites included in the final multivariate model for pregnancy detection, and could differentiate pregnant dogs from non-pregnant ones with excellent sensitivity and specificity.

Discussion

These results increase our understanding of the metabolic consequences of canine reproduction, with the possibility of improving maternal health and ensuring reproductive success. The identified metabolites could be used for confirming canine pregnancy.

Maternal adaptations of the pancreas and glucose homeostasis in lactation and after lactation

During lactation, the maternal physiology adapts to bear the nutritional requirements of the offspring. The exocrine and endocrine pancreas are central to nutrient handling, promoting digestion and metabolism. In concert with prolactin, insulin is a determinant factor for milk synthesis. The investigation of the pancreas during lactation has been scattered over several periods. The investigations that laid the foundation of lactating pancreatic physiology and glucose homeostasis were conducted in the decades of 1970-1980. With the development of molecular biology, newer studies have revealed the molecular mechanisms involved in the endocrine pancreas during breastfeeding. There has been a surge of information recently about unexpected changes in the pancreas at the end of the lactation period and after weaning. In this review, we aim to gather information on the changes in the pancreas and glucose homeostasis during and after lactation and discuss the outcomes derived from the current discoveries.

Ovarian apoptosis is regulated by carbohydrate intake but not by protein intake in speckled cockroaches

When the likelihood of reproducing successfully is low, any prior investment in developing oocytes may be wasted. One means of recouping this investment is oosorption - where ova are absorbed and resources salvaged so they can be re-allocated to other traits. Food-limited female speckled cockroaches (Nauphoeta cinerea) appear to use this strategy. However, it is unclear if total food intake or the availability of specific nutrients induces this process. Here, we used the geometric framework of nutrition to determine how protein, carbohydrate and energy intake affect levels of ovarian apoptosis and necrosis (controlled versus uncontrolled cell death) in the terminal oocytes of female N. cinerea. We then compare the effects of nutrient intake on apoptosis (a key step towards oosorption) and offspring production to better understand the relationship between diet, apoptosis and female fitness. We found that even when food was abundant, females experienced high levels of apoptosis if their diet lacked carbohydrate. Necrosis was reduced when energy intake was high, but largely irrespective of nutrient ratio. Offspring production peaked on a low protein, high carbohydrate nutrient ratio (1_P:7.96_C), similar to that which minimized apoptosis (1_P:7.34_C) but not in the region of nutrient space that minimized necrosis. Thus, females consuming an ideal nutrient blend for reproduction can invest heavily in their current brood without needing to salvage nutrients from developing ova. However, offspring production was more dependent on carbohydrate consumption than apoptosis was, suggesting that the importance of carbohydrate in reproduction goes beyond regulating oosorption. This reliance on carbohydrate for female reproduction may reflect the unusual reproductive and nutritional physiology of speckled cockroaches; attributes that make this species an exciting model for understanding how diet regulates reproduction.

Pregnancy and Metabolic-associated Fatty Liver Disease: A Clinical Update

The intricate relationship between metabolic-associated fatty liver disease (MAFLD) and maternal complications has rapidly become a significant health threat in pregnant women. The presence of MAFLD in pregnancy increases the maternal risk of metabolic complications and comorbidities for both mother and baby. The preexistence or development of MAFLD in pregnancy is a complex multifactorial disorder that can lead to further complications for mother and baby. Therefore, as pregnant women are severely underrepresented in clinical research, there is a great need for a fair inclusion of this group in clinical trials. This review aims to explore the effects of MAFLD during pregnancy in the context of maternal complications and outcomes and explore the effects of pregnancy on the development and progression of MAFLD within the context of maternal obesity, altered metabolic profiles, gestational diabetes and altered hormonal profiles. We also addressed potential implications for the presence of MAFLD during pregnancy and its management in the clinical setting.

Effects of probiotic supplementation on glucose metabolism in pregnant women without diabetes: a systematic review and meta-analysis

Background: The preventive effects of probiotic supplementation against gestational diabetes mellitus (GDM) in pregnant women remain unclear. The objective of this review was to investigate the effect of probiotic supplementation on the profiles of glucose metabolism in pregnant women without diabetes. The published literature was retrieved and screened from PubMed, Embase, Web of Science, CNKI (China National Knowledge Infrastructure), Wanfang, and Cochrane Center Register of Controlled Trails up to April 1^st, 2021. Random controlled trials (RCTs) of probiotic supplementation on pregnant women without GDM were included. Results: 12 RCTs (2213 participants) were eligible for meta-analyses. Overall, probiotic supplementation significantly reduced GDM incidence (Risk Ratio (RR) = 0.62, 95% CI: 0.39-0.99), serum fasting blood glucose (FBG) (Mean Difference (MD) = -0.14 mmol L^-1; 95% CI: -0.26 mmol L^-1, -0.01 mmol L^-1), insulin concentration (MD = -1.91 pmol L^-1, 95% CI: -2.41 to -1.41), the homeostasis model assessment of insulin resistance (HOMA-IR) (MD = -0.32 mmol L^-1; 95% CI: -0.42 mmol L^-1, -0.22 mmol L^-1), and Quantitative Insulin sensitivity Check Index (QUICKI) (MD = 0.02, 95% CI: 0.01,0.03) in pregnant women. Probiotic supplementation had no significant effects on the results of the oral glucose tolerance test (OGTT) (1 h OGTT, MD = -0.10, 95% CI: -0.30, 0.09; 2 h OGTT, MD = -0.06, 95% CI: -0.31, 0.20). Conclusion: This meta-analysis suggested that probiotic supplementation may lead to an improvement in glycemic control and reduction of GDM incidence in pregnant women.

Physical Activity during Pregnancy and Newborn Body Composition: A Systematic Review

The current literature demonstrates that not only is exercise during pregnancy safe, but it has substantial maternal and infant benefits and appears to influence infant growth/size throughout pregnancy and at birth. However, many existing studies have investigated only the effects of prenatal exercise on birth weight. The purpose of this review was to determine the impact or association of maternal physical activity during pregnancy on neonatal body composition assessed between birth and two weeks of age. Electronic database searches were conducted on 29 July 2019 for randomized control trials and cohort studies, with an updated search completed on 8 January 2021. A total of 32 articles that met eligibility criteria were selected for review. Overall, prenatal exercise was not associated with infant body composition at birth. Yet, five of the studies identified suggest that infant body composition could be influenced by higher volumes of mid-to-late term prenatal physical activity. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered in PROSPERO (Registration No. CRD42020160138).

Fetomaternal Expression of Glucose Transporters (GLUTs)—Biochemical, Cellular and Clinical Aspects

Several types of specialized glucose transporters (GLUTs) provide constant glucose transport from the maternal circulation to the developing fetus through the placental barrier from the early stages of pregnancy. GLUT1 is a prominent protein isoform that regulates placental glucose transfer via glucose-facilitated diffusion. The GLUT1 membrane protein density and permeability of the syncytial basal membrane (BM) are the main factors limiting the rate of glucose diffusion in the fetomaternal compartment in physiological conditions. Besides GLUT1, the GLUT3 and GLUT4 isoforms are widely expressed across the human placenta. Numerous medical conditions and molecules, such as hormones, adipokines, and xenobiotics, alter the GLUT’s mRNA and protein expression. Diabetes upregulates the BM GLUT’s density and promotes fetomaternal glucose transport, leading to excessive fetal growth. However, most studies have found no between-group differences in GLUTs’ placental expression in macrosomic and normal control pregnancies. The fetomaternal GLUTs expression may also be influenced by several other conditions, such as chronic hypoxia, preeclampsia, and intrahepatic cholestasis of pregnancy.

Immunometabolic adaptation and immune plasticity in pregnancy and the bi-directional effects of obesity

Mandatory maternal metabolic and immunological changes are essential to pregnancy success. Parallel changes in metabolism and immune function make immunometabolism an attractive mechanism to enable dynamic immune adaptation during pregnancy. Immunometabolism is a burgeoning field with the underlying principle being that cellular metabolism underpins immune cell function. With whole body changes to the metabolism of carbohydrates, protein and lipids well recognised to occur in pregnancy and our growing understanding of immunometabolism as a determinant of immunoinflammatory effector responses, it would seem reasonable to expect immune plasticity during pregnancy to be linked to changes in the availability and handling of multiple nutrient energy sources by immune cells. While studies of immunometabolism in pregnancy are only just beginning, the recognised bi-directional interaction between metabolism and immune function in the metabolic disorder obesity might provide some of the earliest insights into the role of immunometabolism in immune plasticity in pregnancy. Characterised by chronic low-grade inflammation including in pregnant women, obesity is associated with numerous adverse outcomes during pregnancy and beyond for both mother and child. Concurrent changes in metabolism and immunoinflammation are consistently described but any causative link is not well established. Here we provide an overview of the metabolic and immunological changes that occur in pregnancy and how these might contribute to healthy versus adverse pregnancy outcomes with special consideration of possible interactions with obesity.

The energetics of uniquely human subsistence strategies

[Figure: see text].

Breastfeeding Is Inversely Associated with Allostatic Load in Postpartum Women: Cross-Sectional Data from Nationally Representative US Women

BACKGROUND

The postpartum period is a critical transition period when exposures to protective factors such as breastfeeding can have long-lasting health impact. Studies have suggested downregulating effects of breastfeeding on stress biomarkers such as cortisol but have not explored the way breastfeeding interacts with allostatic load, a multisystem indicator of chronic stress.

OBJECTIVE

We aimed to examine the association between breastfeeding and maternal allostatic load among women within 2 y postpartum using nationally representative data.

METHODS

A cross-sectional analysis of 10 waves of data from the NHANES (1999-2018) was conducted in a sample of 1302 women aged ≥18 y who provided information on breastfeeding through the reproductive health questionnaire. Clinical and empirical allostatic load scores (range: 0-10; higher numbers associated with increased risk) were derived for each participant based on 10 biomarkers reflecting metabolic, cardiovascular, and immune health. Multiple linear regression tested associations between breastfeeding and allostatic load, adjusting for maternal age, race and ethnicity, education, poverty level, and survey wave.

RESULTS

Breastfeeding had a significant inverse association with allostatic load in unadjusted and adjusted models. Controlling for age, race and ethnicity, education, poverty level, and survey wave, breastfeeding women had a 0.36-point lower clinical allostatic load score than nonbreastfeeding women (β = -0.36, SE = 0.11; 95% CI: -0.59, -0.14; P = 0.002) and a 0.44-point lower empirical allostatic load score (β = -0.44, SE = 0.15; 95% CI: -0.74, -0.14; P = 0.005).

CONCLUSIONS

Our study suggests that breastfeeding is protective of maternal stress and provides a more comprehensive picture of breastfeeding's influence on multiple body systems, exemplifying physiological benefits beyond effects on single biomarkers. However, limitations of cross-sectional data and non-classification of breastfeeding duration, mode, and intensity should be considered when interpreting these findings, and further research to address the role of breastfeeding and allostatic load is needed.

Metabolic Effects of Breastfeeding in Women with Previous Gestational Diabetes Mellitus: A Meta-Analysis

Objective: To investigate the effects of breastfeeding (BF) on metabolic-related outcomes in women with previous gestational diabetes mellitus. Methods: Databases, including PubMed, Embase, Cochrane Library, and Web of Science, were searched until March 5, 2020. Finally, 14 high-quality articles were included. Relative risk (RR) and weighted mean difference (WMD) with 95% confidence interval (CI) were pooled using Stata14.0 Software. Results: Subjects in the BF group had a lower incidence of diabetes (RR: 0.611, 95% CI: 0.452-0.826, p < 0.001) and lower fasting plasma glucose level (WMD: -4.762, 95% CI: -5.552 to -3.973, p < 0.001), fasting insulin level (WMD: -21.513, 95% CI: -37.594 to -5.431, p = 0.009), homeostasis model assessment of insulin resistance (HOMA-IR) (WMD: -1.107, 95% CI: -1.683 to -0.532, p < 0.001), and triglyceride level (WMD: -33.951, 95% CI: -50.714 to -17.189, p < 0.001) than those in the non-BF group. The high-density lipoprotein level (WMD: 3.855, 95% CI: 2.629-5.081, p < 0.001), low-density lipoprotein level (WMD: 4.223, 95% CI: 0.6712-7.774, p = 0.020), and insulin sensitivity index (WMD: 1.503, 95% CI: 0.857-2.160, p < 0.001) in the BF group were higher than that in the non-BF group. No difference was found in the 2-hour postprandial blood glucose (WMD: -3.804, 95% CI: -8.237 to 0.630, p = 0.093), incidence of prediabetes mellitus (RR: 0.870, 95% CI: 0.750-1.009, p = 0.065), or cholesterol level (WMD: 1.377, 95% CI: -8.178 to 10.931, p = 0.778) between the two groups. Conclusion: BF may improve several metabolic markers and decrease the risk of developing diabetes.

Does Altered Cellular Metabolism Underpin the Normal Changes to the Maternal Immune System during Pregnancy?

Pregnancy is characterised by metabolic changes that occur to support the growth and development of the fetus over the course of gestation. These metabolic changes can be classified into two distinct phases: an initial anabolic phase to prepare an adequate store of substrates and energy which are then broken down and used during a catabolic phase to meet the energetic demands of the mother, placenta and fetus. Dynamic readjustment of immune homeostasis is also a feature of pregnancy and is likely linked to the changes in energy substrate utilisation at this time. As cellular metabolism is increasingly recognised as a key determinant of immune cell phenotype and function, we consider how changes in maternal metabolism might contribute to T cell plasticity during pregnancy.

Elevated lipid oxidation is associated with exceeding gestational weight gain recommendations and increased neonatal anthropometrics: a cross-sectional analysis

BACKGROUND

Deviations from gestational weight gain (GWG) recommendations are associated with unfavorable maternal and neonatal outcomes. There is a need to understand how maternal substrate metabolism, independent of weight status, may contribute to GWG and neonatal outcomes. The purpose of this study was to explore the potential link between maternal lipid oxidation rate, GWG, and neonatal anthropometric outcomes.

METHODS

Women (N = 32) with a lean pre-pregnancy BMI were recruited during late pregnancy and substrate metabolism was assessed using indirect calorimetry, before and after consumption of a high-fat meal. GWG was categorized as follows: inadequate, adequate, or excess. Shortly after delivery (within 48 h), neonatal anthropometrics were obtained.

RESULTS

Using ANOVA, we found that fasting maternal lipid oxidation rate (grams/minute) was higher (p = 0.003) among women with excess GWG (0.1019 ± 0.0416) compared to women without excess GWG (inadequate = 0.0586 ± 0.0273, adequate = 0.0569 ± 0.0238). Findings were similar when lipid oxidation was assessed post-meal and also when expressed relative to kilograms of fat free mass. Absolute GWG was positively correlated to absolute lipid oxidation expressed in grams/minute at baseline (r = 0.507, p = 0.003), 2 h post-meal (r = 0.531, p = 0.002), and 4 h post-meal (r = 0.546, p = 0.001). Fasting and post-meal lipid oxidation (grams/minute) were positively correlated to neonatal birthweight (fasting r = 0.426, p = 0.015; 2-hour r = 0.393, p = 0.026; 4-hour r = 0.540, p = 0.001) and also to neonatal absolute fat mass (fasting r = 0.493, p = 0.004; 2-hour r = 0.450, p = 0.010; 4-hour r = 0.552, p = 0.001).

CONCLUSIONS

A better understanding of the metabolic profile of women during pregnancy may be critical in truly understanding a woman's risk of GWG outside the recommendations. GWG counseling during prenatal care may need to be tailored to women based not just on their weight status, but other metabolic characteristics.

Postpartum Metabolism: How Does It Change from Pregnancy and What are the Potential Implications?

BACKGROUND

Metabolic dysfunction after pregnancy may have serious consequences for a new mother. The purpose of the study was to characterize basic changes that occur in metabolic profiles from late pregnancy through 4-6 months postpartum. A secondary purpose was to determine metabolic factors that may be contributing to postpartum weight retention.

METHODS

Participants (n=25) came in for 2 visits: late pregnancy (~34 weeks gestation) and postpartum (4-6 months). Resting metabolic rate (RMR), respiratory quotient (RQ), and substrate oxidation values were assessed for 15 minutes during fasted conditions. Blood was drawn and skinfold anthropometry was performed to assess additional outcomes (inflammation, insulin resistance, lipid profiles, body composition). The participants completed a number of surveys that examined other lifestyle and demographic data of interest. At the postpartum visit, additional assessments regarding sleep and breastfeeding habits were administered.

RESULTS

RMR was lower during postpartum (1517.2±225.1 kcal/day) compared to pregnancy (1867.9±302.6 kcal/day) (p<0.001), and remained lower when expressing RMR per kg body weight (postpartum: 22.3±2.7 vs pregnant: 23.7±3.4 kcal/kg, (p=0.034). Relative RMR (RMR per kg body weight) was negatively correlated to insulin resistance (HOMA-IR) during postpartum (r=-.463, p=0.034). Maternal HOMA-IR, inflammation (CRP), triglycerides (TAG), and carbohydrate oxidation were all positively correlated to postpartum weight retention (HOMA-IR: r=0.617, p=0.004; CRP: r=0.477, p=0.039, TAG: r=0.463, p=0.040; Carbohydrate Oxidation: (r=0.469, p=0.018).

CONCLUSION

Metabolic rate is lower during postpartum compared to pregnancy, and may be connected to insulin resistance. Maternal insulin resistance, inflammation, blood lipids, and substrate metabolism are all related to postpartum weight retention.

Energy expenditure during pregnancy: a systematic review

CONTEXT

Contrary to nutritional guidelines, accumulating evidence shows that pregnant women's energy intakes remain stable throughout trimesters. Although pregnant women may eat below their needs or underreport their energy intakes, it is also relevant to question how energy requirements - estimated through measurements of energy expenditure (EE) - change throughout pregnancy.

OBJECTIVE

This review examined prospective studies that measured EE during pregnancy, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

DATA SOURCES

PubMed/MEDLINE, Web of Science, Embase, and CINAHL databases were searched to identify relevant publications up to November 14, 2019.

STUDY SELECTION

All studies that measured EE prospectively and objectively during pregnancy were included in this systematic review. Two authors independently screened 4852 references. A total of 32 studies were included in the final analysis.

DATA EXTRACTION

One author extracted data and assessed the risk of bias and a second author did so for a random sample of studies (n = 7; 22%).

DATA ANALYSIS

Increases in resting EE ranged from 0.5% to 18.3% (8-239 kcal), from 3.0% to 24.1% (45-327 kcal), and from 6.4% to 29.6% (93-416 kcal) between early and mid-, mid- and late, and early and late pregnancy, respectively. Increases in total EE ranged from 4.0% to 17.7% (84-363 kcal), from 0.2% to 30.2% (5-694 kcal), and from 7.9% to 33.2% (179-682 kcal) between early and mid-, mid- and late, and early and late pregnancy, respectively. Participants were mainly of normal weight, although many studies did not report important covariates such as prepregnancy body mass index and gestational weight gain adequacy.

CONCLUSIONS

Additional high-quality longitudinal studies (ie, with multiple objective measurements of EE in all periods of pregnancy while considering important confounding variables, like gestational weight gain) are required.

National guidelines on nutrient reference values for the healthy adult population and for pregnant or lactating women are based on heterogeneous sources of evidence: review of guidelines

Many countries provide dietary guidelines for health practitioners and/or the general population. However, there is no general, international guideline serving as a template for national dietary guidelines, and there is little to no consensus regarding reference values for different nutrients. The present review compared 27 national dietary guidelines for healthy adults as well as for pregnant and/or breastfeeding women, and analysed their quality and the evidence behind their recommendations. The guidelines were evaluated for their quality using the instrument Agree II, and found to be heterogeneous (overall quality score 14%-100%) and often insufficient (quality score < 50%) due to missing information about their methodology and sources of evidence. We analysed the evidence (number of studies, study types and publication years) of reference values of a number of nutrients using the five guidelines that provided the highest scores in the Agree II assessment. The reference values varied among guidelines, were rarely based on up-to-date meta-analyses, and were often based on insufficiently reported evidence (22/27 guidelines with quality score < 50%). We recommend systematic reviews of high quality studies to formulate future guidelines, and to use guidelines on how to write guidelines.

Central actions of insulin during pregnancy and lactation

Pregnancy and lactation are highly metabolically demanding states. Maternal glucose is a key fuel source for the growth and development of the fetus, as well as for the production of milk during lactation. Hence, the maternal body undergoes major adaptations in the systems regulating glucose homeostasis to cope with the increased demand for glucose. As part of these changes, insulin levels are elevated during pregnancy and lower in lactation. The increased insulin secretion during pregnancy plays a vital role in the periphery; however, the potential effects of increased insulin action in the brain have not been widely investigated. In this review, we consider the impact of pregnancy on brain access and brain levels of insulin. Moreover, we explore the hypothesis that pregnancy is associated with site-specific central insulin resistance that is adaptive, allowing for the increases in peripheral insulin secretion without the consequences of increased central and peripheral insulin functions, such as to stimulate glucose uptake into maternal tissues or to inhibit food intake. Conversely, the loss of central insulin actions may impair other functions, such as insulin control of the autonomic nervous system. The potential role of low insulin in facilitating adaptive responses to lactation, such as hyperphagia and suppression of reproductive function, are also discussed. We end the review with a list of key research questions requiring resolution.

Maternal production of milk for infants in the neonatal intensive care unit

Mother's own milk (MOM) feeding is a cost-effective strategy to reduce risks of comorbidities associated with prematurity and improve long-term health of infants hospitalized in the Neonatal Intensive Care Unit (NICU). Significant racial and socioeconomic disparities exist in MOM provision in the NICU, highlighting the importance of developing strategies to reduce these disparities. Mothers of infants in the NICU experience many health concerns which may negatively impact lactation physiology. Objective measures of lactation physiology are limited but may assist in identifying mothers at particular risk. Several strategies to assist mothers of hospitalized infants are essential, including maternal education, qualified lactation professionals, early and frequent milk expression with a hospital-grade double electric breast pump, and providing support for transitioning to direct breastfeeding prior to discharge from the NICU.

Effect of breastfeeding on metabolic-related outcomes in women with previous gestational diabetes mellitus: A protocol for systematic review and meta-analysis

BACKGROUND

This meta-analysis was to systematically investigate the effect of breastfeeding on metabolic-related outcomes in women with previous gestational diabetes mellitus (GDM).

METHODS

We will search the online databases of Relevant studies were searched in Pubmed, Embase, Cochrane Library, Web of Science. Relative risk and weighted mean difference with 95% confidence interval will pooled using Stata14.0 software.

CONCLUSION

Our meta-analysis will explore the effect of breastfeeding on metabolic-related outcomes in women with previous GDM and may provide effective treatment options of GDM.

OSF REGISTRATION NUMBER

10.17605/OSF.IO/HA5U8.

Season of birth and biomarkers of early-life environment

OBJECTIVE

Early-life conditions play an important role in human development, affecting health status and survival. Conditions in utero partly depend on the external environment and thus vary in relation to the season of birth. The aim of this study was to investigate if people born in different seasons of the year differ in values of biomarkers that reflect conditions during fetal development.

METHODS

The study was conducted among Polish rural women recruited at the Mogielica Human Ecology Study Site. The participants were 234 women aged 45 to 92 (mean = 60.2; SD = 10.44). The indicators of early-life environment analyzed in the study were: Absolute Finger Ridge Count (AFRC), the difference between mean number of ridge counts in both thumbs and both little fingers (Md15), overall facial fluctuating asymmetry (OFA), central facial asymmetry (CFA), right and left hand 2D:4D.

RESULTS

Values of biomarkers of fetal development did not vary among groups of women born in different seasons of the year.

CONCLUSIONS

Lack of differences in values of biomarkers according to birth season may indicate that: (a) season of birth is not a good indicator of early-life conditions; (b) tested biomarkers do not reliably reflect the prenatal environment; (c) season of birth does not fully overlap with the sensitive periods of biomarker development and thus fails to capture differences in developmental conditions.

Body composition helps: Differences in energy expenditure between pregnant and nonpregnant females

OBJECTIVES

Human pregnancy is associated with important physiological changes that usually increase energetic requirements. However, great variability exists in the costs and mechanisms required to bear pregnancy. Since body mass (BM) and composition are modified during gestation, it is of great interest to compare the influence of BM on energy expenditure (EE) in pregnant and nonpregnant females.

METHODS

BM, body composition, and EE of 77 volunteers (35 pregnant and 42 nonpregnant females) were measured. The pregnant volunteers completed two measurement rounds at 28 and 32 gestation weeks. Differences on the measured parameters were sought, and comparison of regression lines was computed to test how BM affected the EE of the volunteers.

RESULTS

BM and body composition parameters are significantly higher in pregnant females, but EE is not statistically different. Pregnant females have a larger percentage of fat mass, but lower percentage of fat-free mass (FFM). The EE per kg of FFM is similar in both groups. Comparison of regression lines shows that pregnancy does not change the relationship between BM and EE, but for similar BM pregnant females expend less energy than nonpregnant females.

CONCLUSIONS

We propose that their larger percentage of passive body tissues is the reason why pregnant females expend less energy than nonpregnant females of similar BM, without changing the scaling of EE on BM. Thus, pregnancy could not be as energetically constraining as usually assumed, with important consequences for human reproductive ecology.

Breastfeeding and Postpartum Glucose Regulation Among Women With Prior Gestational Diabetes: A Systematic Review

BACKGROUND

Gestational diabetes mellitus is associated with adverse maternal and fetal outcomes and increases subsequent risk of Type 2 diabetes. Researchers have shown that breastfeeding may reduce diabetes risk in women with recent gestational diabetes.

RESEARCH AIM

To assess association between infant feeding and postpartum glucose tolerance in mothers with recent gestational diabetes within 1 year postpartum.

METHODS

A literature search was performed up to December 31, 2019, retrieving articles related to infant feeding, gestational diabetes, and postpartum glucose regulation in four major databases (PubMed, Cochrane, CINAHL, and Embase). Methodological quality was assessed using tools from the United States National Institutes of Health and the National Heart, Lung, and Blood Institute.

RESULTS

The search yielded 15 cohort studies meeting the selection criteria. Of the 15 studies, 13 (86.7%) examined the influence of breastfeeding on postpartum glycemic status, and eight (53.4%) compared the mean blood glucose values between breastfeeding and non-breastfeeding participants. Of the 13 studies that compared postpartum glycemic status, nine (60%) of the research teams found that breastfeeding lowered rates of impaired glucose tolerance, and four (26.7%) showed no significant change. In eight of the studies reporting mean blood glucose values, six (75%) reported significantly lower fasting plasma glucose in breastfeeding participants, with reductions ranging from 3.7 to 7.4 mg/dL (0.2-0.4 mmol/L).

CONCLUSION

Breastfeeding has been associated with improved postpartum glucose regulation in mothers with gestational diabetes. In pregnant women with gestational diabetes, breastfeeding may reduce the risk of Type 2 diabetes, and women with gestational diabetes should be strongly encouraged and supported to breastfeed.

Regulation of maternal-fetal metabolic communication

Pregnancy may be the most nutritionally sensitive stage in the life cycle, and improved metabolic health during gestation and early postnatal life can reduce the risk of chronic disease in adulthood. Successful pregnancy requires coordinated metabolic, hormonal, and immunological communication. In this review, maternal-fetal metabolic communication is defined as the bidirectional communication of nutritional status and metabolic demand by various modes including circulating metabolites, endocrine molecules, and other secreted factors. Emphasis is placed on metabolites as a means of maternal-fetal communication by synthesizing findings from studies in humans, non-human primates, domestic animals, rabbits, and rodents. In this review, fetal, placental, and maternal metabolic adaptations are discussed in turn. (1) Fetal macronutrient needs are summarized in terms of the physiological adaptations in place to ensure their proper allocation. (2) Placental metabolite transport and maternal physiological adaptations during gestation, including changes in energy budget, are also discussed. (3) Maternal nutrient limitation and metabolic disorders of pregnancy serve as case studies of the dynamic nature of maternal-fetal metabolic communication. The review concludes with a summary of recent research efforts to identify metabolites, endocrine molecules, and other secreted factors that mediate this communication, with particular emphasis on serum/plasma metabolomics in humans, non-human primates, and rodents. A better understanding of maternal-fetal metabolic communication in health and disease may reveal novel biomarkers and therapeutic targets for metabolic disorders of pregnancy.

Perinatal depression: Heterogeneity of disease and in animal models

Perinatal depression (PND) can have either an antepartum or postpartum onset. Although the greatest risk factor for PND is previous depression history,de novoPND occurs with the majority of cases occurring in the postpartum. Timing of depression can impact etiology, prognosis, and response to treatment. Thus, it is crucial to study the impact of the heterogeneity of PND for better health outcomes. In this review, we outline the differences between antepartum and postpartum depression onset of PND. We discuss maternal physiological changes that differ between pregnancy and postpartum and how these may differentially impact depression susceptibility. We highlight changes in the maternal steroid and peptide hormone levels, immune signalling, serotonergic tone, metabolic factors, brain morphology, and the gut microbiome. Finally, we argue that studying the heterogeneity of PND in clinical and preclinical models can lead to improved knowledge of disease etiopathology and treatment outcomes.

Lactation Versus Formula Feeding: Insulin, Glucose, and Fatty Acid Metabolism During the Postpartum Period

Milk production may involve a transient development of insulin resistance in nonmammary tissues to support redistribution of maternal macronutrients to match the requirements of the lactating mammary gland. In the current study, adipose and liver metabolic responses were measured in the fasting state and during a two-step (10 and 20 mU/m²/min) hyperinsulinemic-euglycemic clamp with stable isotopes, in 6-week postpartum women who were lactating (n = 12) or formula-feeding (n = 6) their infants and who were closely matched for baseline characteristics (e.g., parity, body composition, and intrahepatic lipid). When controlling for the low insulin concentrations of both groups, the lactating women exhibited a fasting rate of endogenous glucose production (EGP) that was 2.6-fold greater and a lipolysis rate that was 2.3-fold greater than the formula-feeding group. During the clamp, the groups exhibited similar suppression rates of EGP and lipolysis. In the lactating women only, higher prolactin concentrations were associated with greater suppression rates of lipolysis and lower intrahepatic lipid and plasma triacylglycerol concentrations. These data suggest that whole-body alterations in glucose transport may be organ specific and facilitate nutrient partitioning during lactation. Recapitulating a shift toward noninsulin-mediated glucose uptake could be an early postpartum strategy to enhance lactation success in women at risk for delayed onset of milk production.

Inuit metabolism revisited: what drove the selective sweep of CPT1a L479?

This article reassesses historical studies of Inuit metabolism in light of recent developments in evolutionary genetics. It discusses the possible selective advantage of a variant of CPT1a, which encodes the rate limiting enzyme in hepatic fatty acid oxidation. The L479 variant of CPT1a underwent one of the strongest known selective sweeps in human history and is specific to Inuit and Yu'pik populations. Recent hypotheses predict that this variant may have been selected in response to possible detrimental effects of chronic ketosis in communities with very low carbohydrate consumption. Assessing these hypotheses alongside several alternative explanations of the selective sweep, this article challenges the notion that the selection of L479 is linked to predicted detrimental effects of ketosis. Bringing together for the first time data from biochemical, metabolic, and physiological studies inside and outside the Inuit sphere, it aims to provide a broader interpretative framework and a more comprehensive way to understand the selective sweep. It suggests that L479 may have provided a selective advantage in glucose conservation as part of a metabolic adaptation to very low carbohydrate and high protein consumption, but not necessarily a ketogenic state, in an extremely cold environment. A high intake of n-3 fatty acids may be linked to selection through the mitigation of a detrimental effect of the mutation that arises in the fasted state. The implications of these conclusions for our broader understanding of very low carbohydrate metabolism, and for dietary recommendations for Inuit and non-Inuit populations, are discussed.

Associations of appetite sensations and metabolic characteristics with weight retention in postpartum women

Postpartum weight retention (PPWR) is an important risk factor for long-term obesity. Appetite may be a key factor regulating PPWR. The objectives of this study were to determine the associations between (i) PPWR and appetite; and (ii) appetite, lactation, and metabolic characteristics. Data from 49 women at 9 months postpartum contributed to this cross-sectional analysis. Energy expenditure was assessed in a whole-body calorimetry unit for 24 h. Appetite sensations were rated using visual analogue scales. Lactation (min/day) was measured using a 3-day breastfeeding diary. PPWR was negatively associated with fullness (β ± SE; R² = -2.97 ± 0.72; 0.661; P < 0.001), and satiety (-2.75 ± 0.81; 0.617; P = 0.002), and was positively associated with hunger (2.19 ± 1.02; 0.548; P = 0.039), prospective food consumption (PFC; 2.19 ± 0.91; 0.562; P = 0.021), and composite appetite score (CAS; 0.34 ± 0.09; 0.632; P = 0.001). Lactation was associated with higher CAS (39.68 ± 15.56; 0.365; P = 0.015), hunger (3.56 ± 1.61; 0.308; P = 0.033), and PFC (4.22 ± 1.78; 0.314; P = 0.023), and with reduced sensations of fullness (-4.18 ± 1.94; 0.358; P = 0.038) and satiety (-3.83 ± 1.87; 0.295; P = 0.048). Lactation was associated with appetite, which in turn was related to PPWR. Appetite control should be explored to support postpartum weight management strategies. Novelty Postpartum weight retention was associated with appetite sensations, which were assessed throughout the day under conditions in which energy intake and expenditure were precisely matched. Lactation and other maternal metabolic factors, including carbohydrate oxidation and physical activity level may play a role in controlling appetite during the postpartum period.

Clinical insights gained through metabolomic analysis of human breast milk

Introduction: Among the OMICS technologies, that have emerged in recent years, metabolomics has allowed relevant step forwards in clinical research. Several improvements in disease diagnosis and clinical management have been permitted, even in neonatology. Among potentially evaluable biofluids, breast milk (BM) results are highly interesting, representing a fluid of conjunction between mothers newborns, describing their interaction.Areas covered: in this review, updating a previous review article, we discuss research articles and reviews on BM metabolomics and found in MEDLINE using metabolomics, breast milk, neonatal nutrition, breastfeeding, human milk composition, and preterm neonates as keywords.Expert opinion: Our research group has a profound interest in metabolomics research. In 2012, we published the first metabolomic analysis on BM samples, reporting interesting data on its composition and relevant differences with formula milk (FM), useful to improve FM composition. As confirmed by successive studies, such technology can detect the specific BM composition and its dependence on several variables, including lactation stage, gestational age, maternal or environmental conditions. Moreover, since BM contaminants or drug levels can be detected, metabolomics also results useful to determine BM safety. These are only a few practical applications of BM analysis, which will be reviewed in this paper.

Dramatic Remodeling of the Gut Microbiome Around Parturition and Its Relationship With Host Serum Metabolic Changes in Sows

Perinatal care is important in mammals due to its contribution to fetal growth, maternal health, and lactation. Substantial changes in host hormones, metabolism, and immunity around the parturition period may be accompanied by alterations in the gut microbiome. However, to our knowledge, changes in the gut microbiome and their contribution to the shifts in host metabolism around parturition have not been investigated in pigs. Furthermore, pigs are an ideal biomedical model for studying the interactions of the gut microbiota with host metabolism, due to the ease of controlling feeding conditions. Here we report dramatic remodeling of the gut microbiota and the potential functional capacity during the late stages of pregnancy (5 days before parturition, LP) to postpartum (within 6 h after delivery, PO) in both experimental and validated populations of sows (n = 107). The richness of bacteria in the gut of both pregnant and delivery sows significantly decreased, whilst the β-diversity dramatically expanded. The ratio of Bacteroidetes to Firmicutes, and the relative abundance of Prevotella significantly decreased, whilst the relative abundance of the predominant genus Lactobacillus significantly increased from LP to PO state. The predicted functional capacities of the gut microbiome related to amino acid metabolism, the metabolism of cofactors and vitamins, and glycan biosynthesis were significantly decreased from LP to PO state. However, the abundance of the functional capacities associated with carbohydrate and lipid metabolism were increased. Consistent with these changes, serum metabolites enriched at the LP stage were associated with the metabolism of amino acids and vitamins. In contrast, metabolites enriched at the PO stage were related to lipid metabolism. We further identified that the richness and β-diversity of the gut microbiota and the abundance of Lactobacillus accounted for shifts in the levels of bile acid metabolites associated with lipid metabolism. The results suggest that host-microbiota interactions during the perinatal period impact host metabolism. These benefit the lactation of sows by providing energy from lipid metabolism for milk production.

The effect of different amounts of vitamin D supplementation on serum calcidiol, anthropometric status, and body composition in overweight or obese nursing women: a study protocol for a randomized placebo-controlled clinical trial

Background

The optimal vitamin D intake for nursing mothers with overweight or obesity has not been defined. Vitamin D concentrations are associated with body composition indices, particularly body fat mass. Few studies have investigated the relationship between hypovitaminosis D, obesity, anthropometric status, and body composition in nursing women. Thus, the present study aims to investigate whether vitamin D supplementation during lactation will improve vitamin D status, reduce body fat mass, and improve body composition.

Methods/design

In a double-blind, randomized, placebo-controlled, parallel-group trial, after term delivery, 90 healthy women with overweight or obesity will be selected and randomly allocated into three groups to receive 2000 IU/d cholecalciferol (vitamin D3), 4000 IU/d cholecalciferol, or placebo (lactose) for 12 weeks while nursing. Measurements of height, weight, waist circumference, and body composition (fat mass (kg), lean mass (kg), body fat (%), fat mass index, and relative fat mass index) will be taken for all subjects at baseline and after 12 weeks of intervention. In addition, serum 25-hydroxyvitamin D (25(OH)D), parathyroid hormone, calcium, and phosphorus will be measured.

Discussion

This study is the first investigating the effect of different amounts of vitamin D supplementation on serum calcidiol, anthropometric status, and body composition in nursing women with overweight or obesity. Our findings will contribute to the growing body of knowledge regarding the role of vitamin D supplementation in obesity, anthropometric status, and body composition in nursing women.

Trial registration

Iranian Registry of Clinical Trials IRCT20140413017254N6. Registered on 11 April 2018.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3622-y) contains supplementary material, which is available to authorized users.

The influence of energy metabolism on postpartum weight retention

BACKGROUND

Profiling postpartum energy metabolism may assist in optimizing weight management following childbirth.

OBJECTIVES

The aims of this study were to profile total energy expenditure (TEE), resting energy expenditure (REE), exercise energy expenditure, sleep energy expenditure, and respiratory quotient in women at 3 and 9 mo postpartum (3M-PP, 9M-PP, respectively), and to examine the association between energy metabolism and postpartum weight retention (PPWR).

METHODS

In this cohort study, 1-h REE (measured in a whole body calorimetry unit, WBCU) and body composition (BC, measured by dual-energy X-ray absorptiometry) were measured at 3M-PP and 9M-PP (n = 49). Cardiorespiratory fitness [measured by the predicted maximal volume of oxygen consumption (p$\dot{V}$O2 max), n = 47] and 24-h TEE (WBCU, n = 43) were assessed only at 9M-PP. Women were stratified as high (>4.8 kg) or low (≤ 4.8 kg) weight retainers. Two-way mixed repeated-measures ANOVA and longitudinal regression models were applied. Linear regression was used to generate an equation at 3M-PP from the BC data, to predict the REE at 9M-PP.

RESULTS

The fat mass at 3M-PP was positively associated with PPWR at 3M-PP (mean ± SE β: 0.09 ± 0.03; P = 0.005) and 9M-PP (β: 0.11 ± 0.04; P = 0.008), and negatively associated with REE at 3M-PP (β: -0.16 ± 0.02; P < 0.001) and TEE at 9M-PP (β: -0.15 ± 0.03; P < 0.001). REE was negatively associated with PPWR (β: -0.74; 95% CI: -1.29, -0.19; P = 0.0087). REE was 2 kcal/kg higher in low- vs. high-retainers at 3M-PP, and REE and TEE were both 4 kcal/kg higher in low- vs. high-retainers at 9M-PP. Low-retainers demonstrated an increase in REE greater than expected for changes in BC. PPWR was negatively associated with TEE (β: -0.08 ± 0.02; P = 0.0009) and p$\dot{V}$O2 max (β: -0.02 ± 0.01; P = 0.047); p$\dot{V}$O2 max was 7 mL · kg-1 · min-1 higher in low- vs. high-retainers (P = 0.047).

CONCLUSIONS

Energy metabolism, BC, and cardiorespiratory fitness may be associated with weight regulation and its trajectory during the postpartum period. This provides the foundation for future strategies to promote appropriate postpartum weight management.

[Risk factors analysis of gestational diabetes mellitus based on International Association of Diabetes Pregnancy Study Groups criteria]

OBJECTIVE

To study the risk factors for gestational diabetes mellitus (GDM).

METHODS

This retrospective case-control study was conducted among women registered at the Department of Obstetrics of West China Second University Hospital between March, 2016 and May, 2018. The women were divided into case group (GDM) and control group (Non- GDM) according to the diagnosis of GDM based on the International Association of Diabetes Pregnancy Study Groups (IADPSG) criteria. The data including age, education level, ethnicity and other socio-demographic data, as well as the gestational week, parity, polycystic ovary syndrome, family history of diabetes, fat mass, total body water, minerals and other clinical characteristics were collected. Univariate Logistic regression analysis was performed and the variables with statistical difference and clinical significance were included in multivariate Logistic regression analysis to identify the risk factors of GDM.

RESULTS

A total of 3608 pregnant women were included in the study. Univariate logistic analysis revealed that age, previous GDM, intracellular/extracellular water, fat mass, arm circumference, skeletal muscle mass were risk factors for GDM. Multivariate logistic analysis showed that age, previous GDM, family history of DM, and an arm circumference ≥28.5 cm were independent risk factors for GDM after controlling pre-pregnancy BMI. The risk of GDM in pregnant women aged 30-35 years and 36 years or older was 1.883 (P < 0.001) and 2.883 (P < 0.001) times of that in women aged 20-29 years, respectively. Women with a history of GDM had a 6.604 (P < 0.001) greater risk of developing GDM than women without a history of GDM. Compared with those without a family history of diabetes, those with a family history of diabetes were 2.518 times more likely to develop GDM (P < 0.001). Compared with those with an arm circumference no greater than 25.5 cm, pregnant women with an arm circumference over 28.5 cm had an increased risk of GDM by 2.815 times (P < 0.001). High fat free mass was a protective factor for GDM, and compared with a fat free mass below 35.1 kg, a fat free mass over 40.1 kg was associated with a lowered risk of GDM by 0.515 times (P < 0.001).

CONCLUSIONS

The onset of GDM was affected by multiple factors. Age, history of GDM, family history of diabetes, and a large arm circumference are all independent risk factors of GDM and should be controlled to reduce the incidence of GDM.

Longer lactation duration is associated with decreased prevalence of non-alcoholic fatty liver disease in women

BACKGROUND & AIMS

Lactation lowers blood glucose and triglycerides, and increases insulin sensitivity. We hypothesized that a longer duration of lactation would be associated with lower prevalence of non-alcoholic fatty liver disease (NAFLD), which is the leading cause of chronic liver disease in the United States.

METHODS

Participants from the Coronary Artery Risk Development in Young Adults cohort study who delivered ≥ 1 child post-baseline (Y0: 1985-1986), and underwent CT quantification of hepatic steatosis 25 years following cohort entry (Y25: 2010-2011) were included (n = 844). The duration of lactation was summed for all post-baseline births, and NAFLD at Y25 was assessed by central review of CT images and defined by liver attenuation ≤ 40 Hounsfield Units after exclusion of other causes of hepatic steatosis. Unadjusted and multivariable logistic regression analyses were performed using an a priori set of confounding variables; age, race, education, and baseline body mass index.

RESULTS

Of 844 women who delivered after baseline (48% black, 52% white, mean age 49 years at Y25 exam), 32% reported lactation duration of 0 to 1 month, 25% reported >1 to 6 months, 43% reported more than 6 months, while 54 (6%) had NAFLD. Longer lactation duration was inversely associated with NAFLD in unadjusted logistic regression. For women who reported >6 months lactation compared to those reporting 0-1 month, the odds ratio for NAFLD was 0.48 (95% CI 0.25-0.94; p = 0.03) and the association remained after adjustment for confounders (adjusted odds ratio 0.46; 95% CI 0.22-0.97; p = 0.04).

CONCLUSIONS

A longer duration of lactation, particularly greater than 6 months, is associated with lower odds of NAFLD in mid-life and may represent a modifiable risk factor for NAFLD.

LAY SUMMARY

A longer duration of breastfeeding has been associated with multiple potential health benefits for the mother including reduction in heart disease, diabetes and certain cancers. In this study we found that breastfeeding for longer than 6 months was associated with a lower risk of non-alcoholic fatty liver disease in mid-life.

Life history trade-offs and the partitioning of maternal investment: Implications for health of mothers and offspring

Lay Summary: This review sets out the hypothesis that life history trade-offs in the maternal generation favour the emergence of similar trade-offs in the offspring generation, mediated by the partitioning of maternal investment between pregnancy and lactation, and that these trade-offs help explain widely reported associations between growth trajectories and NCD risk. Growth patterns in early life predict the risk of non-communicable diseases (NCDs), but adaptive explanations remain controversial. It is widely assumed that NCDs occur either because of physiological adjustments to early constraints, or because early ecological cues fail to predict adult environmental conditions (mismatch). I present an inter-generational perspective on developmental plasticity, based on the over-arching hypothesis that a key axis of variability in maternal metabolism derives from life history trade-offs, which influence how individual mothers partition nutritional investment in their offspring between pregnancy and lactation. I review evidence for three resulting predictions: (i) Allocating relatively more energy to growth during development promotes the capacity to invest in offspring during pregnancy. Relevant mechanisms include greater fat-free mass and metabolic turnover, and a larger physical space for fetal growth. (ii) Allocating less energy to growth during development constrains fetal growth of the offspring, but mothers may compensate by a tendency to attain higher adiposity around puberty, ecological conditions permitting, which promotes nutritional investment during lactation. (iii) Since the partitioning of maternal investment between pregnancy and lactation impacts the allocation of energy to 'maintenance' as well as growth, it is expected to shape offspring NCD risk as well as adult size and body composition. Overall, this framework predicts that life history trade-offs in the maternal generation favour the emergence of similar trade-offs in the offspring generation, mediated by the partitioning of maternal investment between pregnancy and lactation, and that these trade-offs help explain widely reported associations between growth trajectories and NCD risk.

Energy homeostasis and running wheel activity during pregnancy in the mouse

Pregnancy and lactation are metabolically challenging states, where the mother must supply all the energy requirements for the developing fetus and growing pups respectively. The aim of the current study was to characterize many aspects of energy homeostasis before and during pregnancy in the mouse, and to examine the role of voluntary activity on changes in energy expenditure during pregnancy. In a secondary aim, we evaluate measures of energy homeostasis during pregnancy in mice that successfully reared their litter or in mice that went on to abandon their litter, to determine if an impairment in pregnancy-induced adaptation of energy homeostasis might underlie the abandonment of pups soon after birth. During pregnancy, food intake was increased, characterized by increased meal size and duration but not number of meals per day. The duration of time spent inactive, predicted to indicate sleep behaviour, was increased both early and late in pregnancy compared to pre-pregnancy levels. Increased x + y beam breaks, as a measure of activity increased during pregnancy and this reflected an increase in ambulatory behaviour in mid pregnancy and an increase in non-ambulatory movement in late pregnancy. Energy expenditure, as measured by indirect calorimetry, increased across pregnancy, likely due to the growth and development of fetal tissue. There was also a dramatic reduction in voluntary wheel running as soon as the mice became pregnant. Compared with successful pregnancies and lactations, pregnancies where pups were abandoned soon after birth were associated with reduced body weight gain and an increase in running wheel activity at the end of pregnancy, but no difference in food intake or energy expenditure. Overall, during pregnancy there are multiple adaptations to change energy homeostasis, resulting in partitioning of provisions of energy to the developing fetus and storing energy for future metabolic demands.

Lactation Duration and Progression to Diabetes in Women Across the Childbearing Years: The 30-Year CARDIA Study

Importance

Lactation duration has shown weak protective associations with incident diabetes (3%-15% lower incidence per year of lactation) in older women based solely on self-report of diabetes, studies initiated beyond the reproductive period are vulnerable to unmeasured confounding or reverse causation from antecedent biochemical risk status, perinatal outcomes, and behaviors across the childbearing years.

Objective

To evaluate the association between lactation and progression to diabetes using biochemical testing both before and after pregnancy and accounting for prepregnancy cardiometabolic measures, gestational diabetes (GD), and lifestyle behaviors.

Design, Setting, and Participants

For this US multicenter, community-based 30-year prospective cohort study, there were 1238 women from the Coronary Artery Risk Development in Young Adults (CARDIA) study of young black and white women ages 18 to 30 years without diabetes at baseline (1985-1986) who had 1 or more live births after baseline, reported lactation duration, and were screened for diabetes up to 7 times during 30 years after baseline (1986-2016).

Exposures

Time-dependent lactation duration categories (none, >0 to 6 months, >6 to <12 months, and ≥12 months) across all births since baseline through 30 years.

Main Outcomes and Measures

Diabetes incidence rates per 1000 person-years and adjusted relative hazards (RH) with corresponding 95% CIs, as well as proportional hazards regression models adjusted for biochemical, sociodemographic, and reproductive risk factors, as well as family history of diabetes, lifestyle, and weight change during follow-up.

Results

Overall 1238 women were included in this analysis (mean [SD] age, 24.2 [3.7] years; 615 black women). There were 182 incident diabetes cases during 27 598 person-years for an overall incidence rate of 6.6 cases per 1000 person-years (95% CI, 5.6-7.6); and rates for women with GD and without GD were 18.0 (95% CI, 13.3-22.8) and 5.1 (95% CI, 4.2-6.0), respectively (P for difference < .001). Lactation duration showed a strong, graded inverse association with diabetes incidence: adjusted RH for more than 0 to 6 months, 0.75 (95% CI, 0.51-1.09); more than 6 months to less than 12 months, 0.52 (95% CI, 0.31-0.87), and 12 months or more 0.53 (0.29-0.98) vs none (0 days) (P for trend = .01). There was no evidence of effect modification by race, GD, or parity.

Conclusions and Relevance

This study provides longitudinal biochemical evidence that lactation duration is independently associated with lower incidence of diabetes. Further investigation is required to elucidate mechanisms that may explain this relationship.

Maternal Responses to Aerobic Exercise in Pregnancy

Exercise is one of the most physiologically challenging stressors requiring the coordination of metabolic, respiratory, and cardiovascular responses to meet increased energy requirements of the working muscle. During pregnancy, all women without contraindication are encouraged to exercise as part of a healthy lifestyle. Pregnancy itself is associated with profound physiological adaptations to the maternal cardiovascular, respiratory, and metabolic systems, which serve to support the needs of the growing fetus. Therefore the physiological adaptations to exercise during pregnancy are more pronounced and critically important. This review provides an overview of our current understanding of the physiological adaptations to acute prenatal exercise.

Metabolic effects of breastfeeding in women with previous gestational diabetes diagnosed according to the IADPSG criteria

BACKGROUND

Some studies have already investigated about the short-term favorable metabolic effects of breastfeeding in women with previous gestational diabetes mellitus (GDM).

AIM

The aim of our study is to confirm whether the positive effects reported are maintained in the larger cohorts of patients with mild form of gestational diabetes mellitus (GDM) because recently diagnosed according to IADPSG criteria.

MATERIALS AND METHODS

This retrospective study includes 97 evaluable consecutive women with prior GDM who have the follow-up oral glucose tolerance test at least 3 months after delivery. Fasting and 2-h plasma glucose values, homeostasis model assessment (HOMA-IR), total cholesterol, and triglycerides were obtained in pregnancy and during the post-partum control.

RESULTS

These patients were divided in 81 (83.5%) who lactate until 3 months and 16 (16.5%) who did not lactate. During pregnancy, there are no significant differences between the two groups for age, BMI, fasting and 2-h plasma glucose values, HOMA-IR, total cholesterol and triglycerides. At the postpartum control, we have at univariate analysis significant differences for all these parameters except total cholesterol. After adjustment for confounders we still have, in the breastfeeding group, HOMA-IR reduction (OR 0.370; 95% CI 0.170-0.805; p < .01) as significant independent variable, whose improvement is the most acknowledged important factor for the prevention of abnormal glucose tolerance later in life.

CONCLUSION

These encouraging results confirm our determination to warmly advice the women affected by GDM to breastfeeding at least for 3 months.

The effect of high-intensity breastfeeding on postpartum glucose tolerance in women with recent gestational diabetes

BACKGROUND

Although breastfeeding is expected to reduce the incidence of diabetes in women with gestational diabetes, the effect has not been clearly confirmed. We examined whether or not high-intensity breastfeeding reduces the incidence of abnormal glucose tolerance and investigated the effect of high-intensity breastfeeding on insulin resistance during the first year postpartum in Japanese women with current gestational diabetes.

METHODS

In this retrospective study, we included women with gestational diabetes who underwent postpartum 75 g oral glucose tolerance test during the first year (12-14 months) postpartum from 2009 to 2011 at a single tertiary perinatal care center in Japan. High-intensity breastfeeding was defined as the condition in which infants were fed by breastfeeding alone or 80% or more of the volume. We investigated the effect of high-intensity breastfeeding on the prevalence of postpartum abnormal glucose tolerance and the postpartum homeostasis model of assessment of insulin resistance (HOMA-IR), after controlling for confounders, including prepregnancy obesity and weight changes during pregnancy and postpartum.

RESULTS

Among 88 women with gestational diabetes, 46 (52%) had abnormal glucose tolerance during the postpartum period. High-intensity breastfeeding women (n = 70) were significantly less likely to have abnormal glucose tolerance than non-high-intensity breastfeeding women (n = 18) (46% vs. 78%, p = 0.015). High-intensity breastfeeding was also associated with a lower HOMA-IR at 12-14 months postpartum than non-high-intensity breastfeeding (1.41 ± 1.02 vs. 2.28 ± 1.05, p = 0.035). Those associations remained significant after controlling for confounders. At least six months of high-intensity breastfeeding had a significant effect on lowering both the abnormal glucose tolerance prevalence and HOMA-IR compared with non-high-intensity breastfeeding.

CONCLUSIONS

In Japanese women with gestational diabetes, high-intensity breastfeeding ≥6 months had a protective effect against the development of abnormal glucose tolerance during the first year postpartum through improving insulin resistance, independent of obesity and postpartum weight change.