Calcium economy in human pregnancy and lactation

Hypoparathyroidism and assisted reproductive technology: considerations while undergoing ovarian hyperstimulation

PURPOSE OF REVIEW

Hypoparathyroidism (hypoPTH) is a rare disease that requires diligent adherence to treatment regimens to prevent hypocalcemia but also treatment-induced hypercalcemia and hypercalciuria. The menstrual cycle, pregnancy, and lactation can all impact calcium homeostasis but there is little known regarding the impact of ovarian stimulation. Furthermore, the limited reports suggest no clear association between menstrual phase and calcium balance among those with hypoPTH. With increasing patient utilization of assisted reproductive technology (ART), there is a need for better understanding the care required for patients with hypoparathyroidism pursuing fertility technology.

RECENT FINDINGS

There is currently no literature available on patients with hypoparathyroidism and the impact of controlled ovarian stimulation on calcium homeostasis. We present information regarding physiologic changes in pregnancy that impact calcium homeostasis and the first case presentation of a patient with hypoparathyroidism pursuing ART.

SUMMARY

This article provides the first insights and guidance when providing fertility care for patients with hypoparathyroidism.

Consideration of hormonal changes for orthodontic treatment during pregnancy and lactation - a review

Hormonal changes in pregnant and lactating women significantly affect bone metabolism and overall stress levels, positioning them as a unique group within the orthodontic population. Fluctuations in estrogen, progesterone, prolactin, and other hormones are closely linked to bone remodeling and the periodontal tissue's response to inflammation caused by dental plaque. Hormones such as thyrotropin, leptin, and melatonin also play crucial roles in pregnancy and bone remodeling, with potential implications for orthodontic tooth movement. Additionally, adverse personal behaviors and changes in dietary habits worsen periodontal conditions and complicate periodontal maintenance during orthodontic treatment. Notably, applying orthodontic force during pregnancy and lactation may trigger stress responses in the endocrine system, altering hormone levels. However, these changes do not appear to adversely affect the mother or fetus. This review comprehensively examines the interaction between hormone levels and orthodontic tooth movement in pregnant and lactating women, offering insights to guide clinical practice.

Urinary Silicon Excretion in Relation to Lactation and Bone Mineral Density - a Longitudinal Study Post-partum

Silicon (Si) may be a mineral beneficial for bone health. Pregnancy and lactation have major impacts on maternal bone metabolism as bone minerals, including calcium (Ca), are required for growth of the foetus and for milk production. Like urinary Ca excretion, Si excretion has been reported to be high in pregnant women, but there are no data post-partum and during lactation. The aim of the present study was to investigate the urinary excretion of Si (U-Si), from the third trimester of pregnancy until 18 months post-partum, and in relation to the length of lactation, to determine if changes in U-Si are associated with changes in areal bone mineral density (aBMD). This longitudinal study included 81 pregnant women, of whom 56 completed the study. Spot urine samples were collected at the third trimester and at 0.5, 4, 12, and 18 months post-partum and were analysed for Si and Ca by ICP-OES. The aBMD was measured post-partum at lumbar spine and femoral neck by dual-energy x-ray absorptiometry. Women lactating for 4-8.9 and ≥ 9 months had significantly higher U-Si at 4 months post-partum, compared with the third trimester. No significant longitudinal differences in U-Si were found after correcting for creatinine. Changes in U-Si and in aBMD were not correlated, except at the lumbar spine from 0.5 to 12 months post-partum in the women lactating for 4-8.9 months. Taken together, our results suggest that there is a possibility that U-Si increases post-partum in women lactating for 4 months or longer, although it is not related to changes in aBMD.

Biochemical Markers of Calcium and Bone Metabolism during and after Lactation in Ugandan Women with HIV on Universal Maternal Antiretroviral Therapy

We reported accentuated lactational decreases in areal bone mineral density and only partial skeletal recovery after lactation in Ugandan women with HIV (WWH) initiated on tenofovir disoproxil fumarate-based antiretroviral therapy (TDF-based ART) during pregnancy compared to women without HIV (REF). WWH also had higher breast milk calcium in the first months of lactation. To investigate the mechanisms, we measured bone turnover markers (bone resorption: C-terminal telopeptide [CTX]; bone formation: procollagen type 1 N-terminal propeptide [P1NP], bone-specific and total alkaline phosphatase [BALP, TALP]), hormones (parathyroid hormone [PTH], intact fibroblast growth factor 23 [FGF23], 1,25-dihydroxyvitamin D [1,25(OH)2 D]), vitamin D status (25-hydroxyvitamin D [25OHD]), and indices of mineral metabolism and renal function. Blood and urine samples collected at 36 weeks of gestation, 14 and 26 weeks of lactation, and 3-6 months after lactation were analyzed. Mean 25OHD was >50 nmol/L throughout. Both groups experienced similar biochemical changes during pregnancy and lactation to women in other settings, but within these patterns, the two groups differed significantly. Notably, WWH had higher PTH (+31%) and lower 1,25(OH)2 D (-9%) and TmP/GFR (-9%) throughout, lower P1NP (-27%) and plasma phosphate (-10%) in pregnancy, higher CTX (+15%) and BALP (+19%), and lower eGFR (-4%) during and after lactation. P1NP/CTX ratio was lower in WWH than REF in pregnancy (-21%), less so in lactation (-15%), and similar after lactation. Additionally, WWH had lower plasma calcium (-5%), lower FGF23 (-16%) and fasting urinary calcium (-34%) at one or both lactation timepoints, and higher fasting urinary phosphate (+22%) at 26 weeks of lactation and after lactation. These differences resemble reported TDF effects, especially raised PTH, increased bone resorption, decreased bone formation, and decreased renal function, and may explain the observed differences in bone mineral density and breast milk calcium. Further studies are needed to determine whether HIV and TDF-based ART have long-term consequences for maternal bone health and offspring growth. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

The role of dietary calcium in the etiology of childhood rickets in the past and the present

For more than two centuries, lack of sunlight has been understood to cause vitamin D deficiency and documented as a primary cause of rickets. As such, evidence of rickets in the archeological record has been used as a proxy for vitamin D status in past individuals and populations. In the last decade, a clinical global consensus has emerged wherein it is recognized that dietary calcium deficiency also plays a role in the manifestation of rickets and classic skeletal deformities may not form if dietary calcium is normal even if vitamin D is deficient. This disease is now clinically called "nutritional rickets" to reflect the fact that rickets can take calcium deficiency-predominant or vitamin D deficiency-predominant forms. However, there are currently no paleopathological studies wherein dietary calcium deficiency is critically considered a primary etiology of the disease. We review here the interplay of calcium, vitamin D, and phosphorous in bone homeostasis, examine the role of dietary calcium in human health, and critically explore the clinical literature on calcium deficiency-predominant rickets. Finally, we report a case of rickets from the late Formative Period (~2500-1500 years ago) of the Atacama Desert and argue the disease in this infant is likely an example of calcium deficiency-predominant rickets. We conclude that most archeological cases of rickets are the result of multiple micronutrient deficiencies that compound to manifest in macroscopic skeletal lesions. For clinicians, these factors are important for implementing best treatment practice, and for paleopathologists they are necessary for appropriate interpretation of health in past communities.

Milk Calcium and Phosphorus in Ugandan Women with HIV on Tenofovir-Based Antiretroviral Therapy

BACKGROUND

Breastfed infants depend on human milk calcium and phosphorus for bone mineral accretion and growth. We reported greater mobilization of bone mineral and delayed skeletal recovery in lactating Ugandan women with HIV initiated on tenofovir-based antiretroviral therapy during pregnancy compared to HIV-uninfected counterparts in the Gumba Study. However, it is unknown if these disruptions in maternal bone metabolism affect milk mineral concentrations.

RESEARCH AIM

To compare concentrations and patterns of change in milk calcium and phosphorus between lactating women with and without HIV.

METHODS

A longitudinal observational study was conducted to compare milk mineral concentrations between women with HIV receiving tenofovir-based ART and uninfected women in the Gumba Study. Milk collected at 2, 14, 26, and 52 weeks lactation was analyzed for calcium and phosphorus. Sodium and potassium were measured at 2 and 14 weeks to detect sub-clinical mastitis. Differences in milk composition between 84 women with HIV and 81 uninfected women were investigated.

RESULTS

Women with HIV had higher milk calcium than uninfected women at 14 weeks. The percent difference was +10.2% (SE = 3.0, p = .008) and there was a tendency to greater values at 2 and 26 weeks. Milk calcium decreased in both groups during lactation (p ≤ .001) but was more pronounced in women with HIV. The magnitude of change within individuals in the 1st year of lactation from 2 to 52 weeks was -28.3% (SE 3.9) versus -16.5% (SE 3.5), p for interaction = .05. Differences in milk phosphorus and calcium-to-phosphorus ratio were smaller and mostly not significant.

CONCLUSIONS

Participants with HIV on tenofovir-based antiretroviral therapy had altered milk mineral composition. Studies are needed to investigate mechanisms and health implications for the woman and infant.

Individualized high dairy protein + walking program supports bone health in pregnancy: a randomized controlled trial

BACKGROUND

Pregnancy induces bone mineral mobilization, which may be further compromised if diet and physical activity are suboptimal.

OBJECTIVES

We aimed to determine the effects of a Nutrition + Exercise intervention during pregnancy on maternal calciotropic and bone biomarker profiles throughout pregnancy and the postpartum.

METHODS

In the Be Healthy in Pregnancy (BHIP) randomized controlled trial, 203 of 225 participants who consented to the bone health substudy were, randomly assigned at 12-17 weeks gestation to receive either usual care (control) or a structured and monitored Nutrition + Exercise plan (intervention) providing an individualized high dairy protein diet and a walking program throughout pregnancy. Maternal serum total procollagen type 1 N-terminal propeptide (P1NP; bone formation), C-terminal telopeptide of type I collagen (CTX; bone resorption), and insulin-like growth factor-1 (IGF-1) were measured by ELISA, and vitamin D metabolites by ultra-performance LC tandem MS at early and late pregnancy, 6 mo postpartum, and in cord blood.

RESULTS

In 187 participants completing all measures, significantly higher intakes were observed in the intervention than in the control group for total protein (P < 0.0001), protein intake from dairy foods (P < 0.0001), and calcium (P < 0.0001), whereas vitamin D intake was similar between treatment groups in both the second and third trimesters. The intervention group had significantly lower serum CTX at end of pregnancy (mean ± SD: 0.78 ± 0.31 ng/mL; n = 91 compared with 0.89 ± 0.33 ng/mL; n = 96, P = 0.034) and in cord serum (0.58 ± 0.13 ng/mL; n = 31 compared with 0.69 ± 0.18 ng/mL; n = 22, P < 0.025). Serum concentrations of P1NP rose significantly (P < 0.02) from early pregnancy to 6 mo postpartum for the intervention group only. Serum 25-hydroxyvitamin D status was >50 nmol/L for 97% of all participants.

CONCLUSIONS

Higher maternal dietary protein and calcium intakes than usual care in concert with normal vitamin D status minimized bone resorption and maintained bone formation and may protect bone health during pregnancy.This trial was registered at clinicaltrials.gov as NCT01689961.

Human milk: From complex tailored nutrition to bioactive impact on child cognition and behavior

Human milk is a highly complex liquid food tailor-made to match an infant's needs. Beyond documented positive effects of breastfeeding on infant and maternal health, there is increasing evidence that milk constituents also impact child neurodevelopment. Non-nutrient milk bioactives would contribute to the (long-term) development of child cognition and behavior, a process termed 'Lactocrine Programming'. In this review we discuss the current state of the field on human milk composition and its links with child cognitive and behavioral development. To promote state-of-the-art methodologies and designs that facilitate data pooling and meta-analytic endeavors, we present detailed recommendations and best practices for future studies. Finally, we determine important scientific gaps that need to be filled to advance the field, and discuss innovative directions for future research. Unveiling the mechanisms underlying the links between human milk and child cognition and behavior will deepen our understanding of the broad functions of this complex liquid food, as well as provide necessary information for designing future interventions.

Pr-AKI: Acute Kidney Injury in Pregnancy – Etiology, Diagnostic Workup, Management

Despite significant improvements in inpatient and outpatient management, pregnancy-related acute kidney injury (Pr-AKI) remains an important risk factor for early and late maternal and fetal morbidity and mortality. There is a discrepancy between the incidence of Pr-AKI in developing and in developed countries, with the former experiencing a decrease and the latter an increase in Pr-AKI in recent decades. Whereas septic and hemorrhagic complications predominated in the past, nowadays hypertensive disorders and thrombotic microangiopathy are the leading causes of Pr-AKI. Modern lifestyles and the availability and widespread use of in-vitro fertilization techniques in industrialized countries have allowed more women of advanced age to become pregnant. This has led to a rise in the percentage of high-risk pregnancies due to the disorders and comorbidities inherent to or accompanying aging, such as diabetes, arterial hypertension and preexisting chronic kidney disease. Last but not least, the heterogeneity of symptoms, the often overlapping clinical and laboratory characteristics and the pathophysiological changes related to pregnancy make the diagnosis and management of Pr-AKI a difficult and challenging task for the treating physician. In addition to general supportive management strategies such as volume substitution, blood pressure control, prevention of seizures or immediate delivery, each disease entity requires a specific therapy to reduce maternal and fetal complications. In this review, we used the current literature to provide a summary of the physiologic and pathophysiologic changes in renal physiology which occur during pregnancy. In the second part, we present common and rare disorders which lead to Pr-AKI and provide an overview of the available treatment options.

No effect of calcium and vitamin D intake on maternal blood pressure in a healthy pregnant population

OBJECTIVES

Clinical studies have reported an inverse relationship between calcium and vitamin D intake and hypertensive disorders of pregnancy (HDP). The aim of this study was to investigate if there was an association between calcium/vitamin D intake, and vitamin D (25OHD) status, and maternal blood pressure (BP), during pregnancy and at 5-year follow-up.

STUDY DESIGN

This was an observational study of 415 women who participated in the ROLO (Randomised cOntrolled trial of LOw glycaemic index diet for the prevention of recurrence of macrosomia) study. Maternal BP measurements were taken during each trimester and at 5-year follow-up. Calcium and vitamin D intake were determined at each trimester and 25OHD was measured in early and late pregnancy.

RESULTS

Over two-thirds of the cohort were vitamin D sufficient (25OHD > 30 nmol/L) and had adequate calcium intake (>750 mg/day). There was no correlation between calcium intake or vitamin D intake and maternal BP in trimester 1 to 3 or at 5-year follow-up. Vitamin D status at 13 weeks' gestation negatively correlated with mean arterial pressure in trimester 1 (r = -0.152, p = 0.044). There was no correlation however between 25OHD at 28 weeks' gestation and BP at 28 or 34 weeks' gestation or 25OHD and BP at 5-year follow-up.

CONCLUSIONS

In a healthy population of women with adequate calcium and vitamin D intake, no clinically significant correlation existed between calcium and vitamin D and maternal BP.

Pregnancy-Related Change in pQCT and Bone Biochemistry in a Population With a Habitually Low Calcium Intake

In pregnancy, changes in maternal calcium (Ca) economy occur to satisfy fetal Ca demand. It is unclear whether maternal mineral reserves facilitate these requirements and no data exist from sub-Saharan Africa. The aim was to determine skeletal changes with peripheral quantitative computed tomography (pQCT) and bone biochemistry between early second and third trimesters. Pregnant rural Gambians aged 18 to 45 years (n = 467) participating in a trial of antenatal nutritional supplements (ISRCTN49285450) had pQCT scans and blood collections at mean (SD) 14 (3) and 31 (1) weeks' gestation. Outcomes were pQCT: radius/tibia 4% total volumetric bone mineral density (vBMD), trabecular vBMD, total cross-sectional area (CSA), 33%/38% radius/tibia cortical vBMD, bone mineral content (BMC), total CSA; biochemistry: collagen type 1 cross-linked β-C-telopeptide (β-CTX), type 1 procollagen N-terminal (P1NP), parathyroid hormone (PTH), and 1,25(OH)₂ D. Independent t tests tested whether pooled or within-group changes differed from 0. Multiple regression was performed adjusting for age. Data for change are expressed as mean (confidence interval [CI] 2.5, 97.5%). Radius trabecular vBMD, cortical vBMD, and BMC increased by 1.15 (0.55, 1.75)%, 0.41 (0.24, 0.58)%, and 0.47 (0.25, 0.69)%. Tibia total and trabecular vBMD increased by 0.34 (0.15, 0.54)% and 0.46 (0.17, 0.74)%, while tibia cortical vBMD, BMC, and cortical CSA increased by 0.35 (0.26, 0.44)%, 0.55 (0.41, 0.68)% and 0.20 (0.09, 0.31)%, respectively. CTX, PTH, and 1,25(OH)₂ D increased by 23.0 (15.09, 29.29)%, 13.2 (8.44, 19.34)%, and 21.0 (17.67, 24.29)%, while P1NP decreased by 32.4 (-37.19, -28.17)%. No evidence of mobilization was observed in the peripheral skeleton. Resorption, although higher in late versus early gestation, was lower throughout pregnancy compared with non-pregnant non-lactating (NPNL) in the same community. Formation was lower in late pregnancy than in early, and below NPNL levels. This suggests a shift in the ratio of resorption to formation. Despite some evidence of change in bone metabolism, in this population, with habitually low Ca intakes, the peripheral skeleton was not mobilized as a Ca source for the fetus. © 2021 crown copyright . Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). The article published with the permission of the Controller of HMSO and the Queen's Printer of Scotland..

Hard facts and misfits: essential ingredients of public health nutrition research

Policy decisions and the practice of public health nutrition need to be based on solid evidence, developed through rigorous research studies where objective measures are used and results that run counter to dogma are not dismissed but investigated. In recent years, enhancements in study designs, and methodologies for systematic reviews and meta-analysis, have improved the evidence-base for nutrition policy and practice. However, these still rely on a full appreciation of the strengths and limitations of the measures on which conclusions are drawn and on the thorough investigation of outcomes that do not fit expectations or prevailing convictions. The importance of ‘hard facts’ and ‘misfits’ in research designed to advance knowledge and improve public health nutrition is illustrated in this paper through a selection of studies from different stages in my research career, focused on the nutritional requirements of resource-poor populations in Africa and Asia.

Reduction in Bone Loss from 5 to 20 Weeks Postpartum in Adolescents Supplemented with Calcium Plus Vitamin D during Pregnancy Is Not Sustained at 1 Year Postpartum: Follow-up Study of a Randomized Controlled Trial

BACKGROUND

Calcium plus vitamin D supplementation of pregnant Brazilian adolescents with habitually low calcium intake (∼600 mg/d) reduced bone loss during the first 20 wk postpartum.

OBJECTIVE

We investigated maternal bone mass changes during the first year postpartum as a follow-up of the clinical trial.

METHODS

Pregnant adolescents (14-19 y) received calcium (600 mg/d) plus cholecalciferol (200 IU/d) supplementation (n = 30) or placebo (n = 26) from 26 wk of gestation until parturition. Bone area and bone mineral content and bone mineral density (BMD) at total body, lumbar spine, and hip (total and femoral neck) were assessed by DXA at 3 time points postpartum (5 wk, 20 wk, and 56 wk). Intervention group, time postpartum, and group × time interaction effects were tested by repeated-measures mixed-effects models adjusting for calcium intake, return of menses, breastfeeding practices, and body weight.

RESULTS

Time (P < 0.05) but not group affected several absolute bone measurements. There was a group × time interaction for femoral neck BMD (P = 0.045). Mean ± SE values (g/cm2) at 5 wk, 20 wk, and 56 wk were, respectively, 1.025 ± 0.026, 0.980 ± 0.026, and 1.022 ± 0.027 for the placebo group and 1.057 ± 0.025, 1.030 ± 0.024, and 1.055 ± 0.025 for the supplemented group. An interaction also was observed for percentage change in femoral neck BMD relative to 5 wk (P = 0.049), with a more pronounced decrease in the placebo group (-4.58 ± 0.42%) than in the supplemented group (-3.15% ± 0.42%) at 20 wk (P = 0.019), and no difference between groups at 56 wk (-0.44% ± 0.71% in the placebo and -0.76% ± 0.62% in the supplemented group; P = 0.65).

CONCLUSIONS

Calcium plus vitamin D supplementation of the adolescent mothers reduces the magnitude of bone loss at the femoral neck from 5 to 20 wk postpartum without an effect on bone changes after 1 y postpartum, indicating that there is no sustained effect of the supplement tested.

Sex differences in requirements for micronutrients across the lifecourse

For many people, micronutrient requirement means the amount needed in the diet to ensure adequacy. Dietary reference values (DRV) provide guidance on the daily intake of vitamins and minerals required to ensure the needs of the majority in the population are covered. These are developed on estimates of the quantity of each micronutrient required by the average person, the bioavailability of the micronutrient from a typical diet and the interindividual variability in these amounts. Sex differences are inherent in the requirements for many micronutrients because they are influenced by body size or macronutrient intake. These are reflected in different DRV for males and females for some micronutrients, but not all, either when data from males and females are combined or when there is no evidence of sex differences. Pregnancy and lactation represent times when micronutrient requirements for females may differ from males, and separate DRV are provided. For some micronutrients, no additional requirement is indicated during pregnancy and lactation because of physiological adaptations. To date, little account has been taken of more subtle sex differences in growth and maturation rates, health vulnerabilities and in utero and other programming effects. Over the years, the MRC Nutrition and Bone Health Group has contributed data on micronutrient requirements across the lifecourse, particularly for calcium and vitamin D, and shown that supplementation can have unexpected sex-specific consequences that require further investigation. The present paper outlines the current issues and the need for future research on sex differences in micronutrient requirements.

Antenatal iron supplementation, FGF23, and bone metabolism in Kenyan women and their offspring: secondary analysis of a randomized controlled trial

BACKGROUND

Fibroblast growth factor-23 (FGF23) regulates body phosphate homeostasis primarily by increasing phosphaturia. It also acts as a vitamin D-regulating hormone. Maternal iron deficiency is associated with perturbed expression and/or regulation of FGF23 and hence might be implicated in the pathogenesis of hypophosphatemia-driven rickets in their offspring.

OBJECTIVES

We aimed to determine the effect of antenatal oral iron supplementation on FGF23 concentration and maternal and infant markers of bone-mineral regulation.

METHODS

We performed a secondary analysis of a trial in which 470 rural Kenyan women with singleton pregnancies and hemoglobin concentrations ≥ 90 g/L were randomly allocated to daily, supervised supplementation with 60 mg elemental iron as ferrous fumarate or placebo from 13-23 weeks of gestation until 1 mo postpartum. As previously reported, iron supplementation improved iron status in mothers and neonates. For the present study, we reanalyzed all available plasma samples collected in mothers and neonates at birth, with primary outcomes being concentrations of FGF23, measured by 2 assays: 1 that detects intact hormone and C-terminal cleavage products (total-FGF23) and another that detects the intact hormone only (intact-FGF23).

RESULTS

Analysis was performed on 433 women (n = 216, iron group; n = 217, placebo group) and 414 neonates (n = 207, iron group; n = 207, placebo group). Antenatal iron supplementation reduced geometric mean total-FGF23 concentrations in mothers and neonates by 62.6% (95% CI: 53.0%, 70.3%) and 15.2% (95% CI: -0.3%, 28.4%, P = 0.06), respectively. In addition, it increased geometric mean neonatal intact-FGF23 concentrations by 21.6% (95% CI: 1.2%, 46.1%), increased geometric mean maternal hepcidin concentrations by 136.4% (95% CI: 86.1%, 200.3%), and decreased mean maternal 25-hydroxyvitamin D concentrations by 6.1 nmol/L (95% CI: -11.0, -1.2 nmol/L).

CONCLUSIONS

Analysis of this randomized trial confirms that iron supplementation can reverse elevated FGF23 production caused by iron deficiency in iron-deficient mothers and their neonates. Further investigations are warranted to assess to what extent iron supplementation can prevent FGF23-mediated hypophosphatemic rickets or osteomalacia.

Vegetarian diets during pregnancy: effects on the mother's health. A systematic review

While interest in vegetarian nutrition has been steadily increasing, some aspects have not yet been consistently investigated. One topic requiring evidence-based confirmation is the adoption of a vegetarian diet during pregnancy and lactation. Maternal diet is not only correlated with the fetus's and infant's health, but appears relevant for that of the mother as well. Not only is an adequate delivery of nutrients to the fetus and infant mandatory, but the increased physiological needs of the maternal body require an adequate supply of nutrients and can represent harmful stress events that may lead to well-defined pathological conditions. In this review, we aim to systematically investigate state-of-the-art of vegetarian diets during pregnancy and lactation, focusing on maternal nutritional status and pregnancy outcomes. Data are scarce, often inconsistent and not homogeneous for many of the topics we considered, mainly because only a few studies have been performed in developed countries, whereas other studies have derived from developing countries, where vegetarianism can be a proxy indicator of malnutrition. For this reason, we did not find sufficient data to provide evidence-based information and recommendations. To date, the available literature does not clearly support a negative impact on the mother's health and pregnancy outcomes, but, analogously with the findings in the vegetarian adult population, an improvement in the quality of studies might facilitate finding more information on the possible positive impact of well-planned vegetarian diets during pregnancy and lactation. More epidemiological and interventional studies are warranted, in order to address the question as to whether vegetarian nutrition represents an advantage for the mother or poses nutritional issues that need further attention.

Hypocalcaemia and calcium intake in pregnancy: A research protocol for critical analysis of risk factors, maternofoetal outcomes and evaluation of diagnostic methods in a third-category health facility, Cameroon

INTRODUCTION

Hypocalcaemia in pregnancy remains a major health issue, particularly in the developing world where daily calcium intakes are suboptimal. This electrolyte imbalance can lead to severe maternofoetal and childhood consequences. Calcium supplementation, amongst others, contributes significantly to meeting calcium demands in pregnancy. With ionised calcaemia as the gold standard for diagnosis, total calcaemia and albumin-corrected calcaemia in other pathological states have been found to overestimate the burden of hypocalcaemia. The main objectives of this study are to describe the blood calcium level (total, albumin corrected, and ionised calcaemia) and associated maternofoetal outcomes while identifying determinants of calcium supplementation and ionised hypocalcaemia. This study will also evaluate the sensitivity and specificity of albumin corrected calcaemia as a diagnostic tool for hypocalcaemia (ionised calcaemia as the gold standard) among pregnant women in the Nkongsamba Regional Hospital, Cameroon.

METHODS

Our study will target a total of 1067 term pregnant women who shall be included consecutively into the study as they arrive the maternity of the Nkongsamba Regional Hospital for their last antenatal care visit. Data shall be collected using a semi-structured interview-administered questionnaire and blood samples collected for total plasma calcium, albumin and serum ionized calcium assays. Additional data will be collected at birth (maternal and foetal variables; foetal outcomes evaluated as secondary outcomes). Total calcaemia and albuminemia shall be measured by atomic absorption spectrophotometry, while ionised calcaemia will be measured by ion-selective electrode potentiometry(using MSLEA15-H electrolyte analyzer) per standard BIOLABO and MSLEA15 protocols, respectively. Data will be analysed using the statistical softwares epi-Info version 7.2.2.16 and STATA version 16.

EXPECTED RESEARCH OUTCOME

This study will present a more precise estimate of the burden of hypocalcaemia in late pregnancy as well as identify and analyse the different factors associated with calcium supplementation and ionised hypocalcaemia among term pregnant women in a developing world setting. Maternofoetal outcomes associated with hypocalcaemia will be determined as well as the sensitivity and specificity of total and albumin-corrected calcaemia in diagnosing hypocalcaemia. Our findings will contribute significantly to designing or strengthening interventions to control this electrolyte imbalance.

Kidney Physiology in Pregnancy

A woman's body undergoes a myriad of changes throughout the course of a normal gestation. The kidneys play a central role in driving adjustments that guarantee maternal and fetal well-being, including a dramatic increase in glomerular filtration rate, alterations in tubular function, and changes in electrolyte and acid/base handling. Early in gestation, systemic vasodilation, driven by both a change in quantity of and response to various hormones, leads to increased renal blood flow and glomerular filtration rate. Vasodilation also results in activation of the renin-angiotensin-aldosterone axis, which combined with changing tubular handling causes alterations in total body stores of electrolytes and total body water, resulting in a lower serum sodium concentration. In addition, mild proteinuria, glucosuria, and a decrease in serum calcium and magnesium are common. The primary acid/base change seen in pregnancy is a mild respiratory alkalosis due to progesterone effects. This article provides an overview of the current understanding of the healthy response of the kidneys to pregnancy, an understanding of which is key to caring for the pregnant patient, and early identification of alterations that may indicate underlying kidney pathology in pregnancy.

Changes in Bone Mineral Density During and After Lactation in Ugandan Women With HIV on Tenofovir-Based Antiretroviral Therapy

Antiretroviral therapy (ART) in people living with human immunodeficiency virus (HIV) is associated with bone loss, but data are limited in lactation, when physiological bone mineral mobilization is occurring. This research charted changes in areal bone mineral density (aBMD) during and after lactation in Ugandan women with HIV (WWH) initiated onto ART in pregnancy, compared to women without HIV (REF). One-hundred WWH on tenofovir-based ART and 100 REF were enrolled in pregnancy. Lumbar spine (LS), total hip (TH), and whole-body-less-head (WBLH) aBMD were measured by dual-energy X-ray absorptiometry (DXA) at 2, 14, and 26 weeks of lactation, and at 3 months postlactation. The primary outcome was the difference between groups in mean percent change in LS aBMD between 2 and 14 weeks. Statistical analysis was performed in hierarchical repeated measures ANOVA models that corrected for multiple testing. Median age was 23.4 (IQR, 21.0 to 26.8) years. WWH had lower body weight. aBMD decreased in both groups during lactation, but WWH had greater decreases at TH (2-to-26 weeks: WWH [n = 63] -5.9% [95% CI, -6.4 to -5.4] versus REF [n = 64] -4.3% [95% CI, -4.8 to -3.8]; group*time point interaction p = .008). Decreases in LS aBMD were similar in WWH and REF (2-to-26 weeks: -2.0% [95% CI, -2.5 to -1.5]), although there was a tendency toward a smaller decrease in WWH between 2 and 14 weeks (WWH [n = 77] -1.8% [95% CI, -2.2 to -1.4] versus REF [n = 69] -2.9% [95% CI, -3.3 to -2.5]; group*time point interaction p = .08). Postlactation, LS aBMD was higher relative to week 2 in both groups. TH and WBLH aBMD did not return to week 2 values in WWH but did in REF (TH postlactation versus week 2: WWH [n = 61] -3.1% [95% CI, -3.6 to -2.6]; REF [n = 29] +0.1% [95% CI, -0.9 to +1.1]). These data show accentuated bone loss during lactation and only partial skeletal recovery by 3 months postlactation in Ugandan WWH on tenofovir-based ART. Studies are ongoing to understand longer-term consequences for bone health. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

Nutritional and Non-nutritional Composition of Human Milk Is Modulated by Maternal, Infant, and Methodological Factors

Human milk (HM) is dynamic and shows a high inter- and intra-individual variability. To characterize HM with precision, it is necessary to understand the factors that modulate its composition. The objective of this narrative review is to summarize the maternal, infant and methodological factors that affect HM composition. We searched SCOPUS and PubMed databases for articles related to factors that are known to or could potentially influence HM composition and volume across lactation periods. Our comprehensive review encompasses various maternal-, infant-related, and methodological factors that modulate aspects of HM composition including macro- and micronutrients, vitamins and minerals, as well as volume. The most profound changes were observed in HM lipids and lipophiles. Evidence exists for many of the infant-related factors known to affect the nutritive and non-nutritive components of HM (e.g., birth weight, gestational age, infant age/stage of lactation). In contrast, less is known with respect to maternal factors; where there is either limited research or conflicting evidence (e.g., maternal lifestyle, obstetric history, medical conditions), except for the mother's diet, for which there is a relatively well-established understanding. Equally, although many of the methodological factors (e.g., HM sampling, handling and analytics) are known to impact HM composition, few studies have investigated this as a primary outcome, making it an important area of future research in HM. Here we propose a systematic capture of numerous maternal- and infant-related characteristics to facilitate associative comparisons of HM data within and across studies. Additionally, it would be prudent to standardize the methodological aspects known to affect HM composition in analytics, not only for HM lipids and lipophiles, but also for those nutrients whose variability is yet less well-understood. Defining the factors determining HM composition with accuracy will open perspectives for maternal intervention to optimize milk composition for specific needs of infants.

Low protein intake during reproduction compromises the recovery of lactation-induced bone loss in female mouse dams without affecting skeletal muscles

Lactation-induced bone loss occurs due to high calcium requirements for fetal growth but skeletal recovery is normally achieved promptly postweaning. Dietary protein is vital for fetus and mother but the effects of protein undernutrition on the maternal skeleton and skeletal muscles are largely unknown. We used mouse dams fed with normal (N, 20%) or low (L, 8%) protein diet during gestation and lactation and maintained on the same diets (NN, LL) or switched from low to normal (LN) during a 28 d skeletal restoration period post lactation. Skeletal muscle morphology and neuromuscular junction integrity was not different between any of the groups. However, dams fed the low protein diet showed extensive bone loss by the end of lactation, followed by full skeletal recovery in NN dams, partial recovery in LN and poor bone recovery in LL dams. Primary osteoblasts from low protein diet fed mice showed decreased in vitro bone formation and decreased osteogenic marker gene expression; promoter methylation analysis by pyrosequencing showed no differences in Bmpr1a, Ptch1, Sirt1, Osx, and Igf1r osteoregulators, while miR-26a, -34a, and -125b expression was found altered in low protein fed mice. Therefore, normal protein diet is indispensable for maternal musculoskeletal health during the reproductive period.

Calcium supplementation for improving bone density in lactating women: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Clinical trials evaluating the effect of calcium supplementation on bone loss in lactating women have been small, with inconsistent results.

OBJECTIVES

We aimed to determine the effect of calcium supplementation on bone mineral density (BMD) in lactating women.

METHODS

An electronic search of databases was conducted from inception to January 2020. Two authors screened studies, extracted data, and assessed the risk of bias of eligible studies. Percentage change in BMD was pooled using random-effects models and reported as weighted mean differences (WMDs) with 95% CIs. Risk of bias was assessed using the Cochrane risk of bias tool.

RESULTS

Five randomized controlled trials including 567 lactating women were included. All had a high risk of bias. Mean baseline calcium intake ranged from 562 to 1333 mg/d. Compared with control groups (placebo/no intervention), calcium supplementation (600/1000 mg/d) had no significant effect on BMD at the lumbar spine (WMD: 0.74%; 95% CI: -0.10%, 1.59%; I2 = 47%; 95% CI: 0%, 81%; n = 527 from 5 trials) or the forearm (WMD: 0.53%; 95% CI: -0.35%, 1.42%; I2 = 55%; 95% CI: 0%, 85%; n = 415 from 4 trials). BMD at other sites was assessed in single trials: calcium supplementation had a small to moderate effect on total-hip BMD (WMD: 3.3%; 95% CI: 1.5%, 5.1%) but no effect on total body or femoral neck BMD.

CONCLUSIONS

Overall, the meta-analysis indicates that calcium supplementation does not provide clinically important benefits for BMD in lactating women. However, there was adequate dietary intake before supplementation in some studies, and others did not measure baseline calcium intake. Advising lactating women to meet the current recommended calcium intakes (with supplementation if dietary intake is low) is warranted unless new high-certainty evidence to the contrary from robust clinical trials becomes available. More research needs to be done in larger samples of women from diverse ethnic and racial groups.This systematic review was registered at www.crd.york.ac.uk/prospero as CRD42015022092.

Foods to Avoid While Breastfeeding? Experiences and Opinions of Polish Mothers and Healthcare Providers

Popular beliefs regarding a mother’s diet during lactation have a significant impact on breastfeeding practices among mothers, as well on breastfeeding counseling among healthcare providers worldwide. The objective of this study was to assess mothers’ and medical professionals’ knowledge and opinions on the “lactating mother’s diet”. An electronic survey, prepared in Polish, was administered to healthcare providers, as well as mothers who have breastfed a child. The chi-square test, logistic regression, and Mann Whitney U test were used for statistical calculations. Out of a total of 1180 responses received, 1159 were analyzed, and 21 were excluded because they did not meet the inclusion criteria. The survey was completed by 407 (35%) medical healthcare providers and 752 (65%) lactating mothers in non-medical professions. In total, the study included 1074 mothers who have breastfed a child, and 29.14% of them reported that they eliminated certain foods from their diet when breastfeeding. There was no statistically significant difference in the responses received from mothers and medical staff providing maternal care (for each of 17 products, e.g., steak tartare, sushi, legumes, dairy products, p > 0.05 by the Mann-Whitney test). However, a logistic regression revealed some significant correlations with other variables (e.g., duration of lactation). The respondents revealed an appropriate level of knowledge on nutrition during lactation and the majority of participants neither adhered to nor recommended a prophylactic elimination diet. Among other evaluated factors, the experience of following an elimination diet affected respondents’ knowledge of nutrition during breastfeeding. Both mothers and healthcare providers require good nutritional education.

Gestational hypercalcemia: Prevalence and biochemical profile

Gestational hypercalcemia is associated with an increased risk of maternal, fetal and neonatal morbidity and mortality. Hypercalcemia may develop during pregnancy in individuals who were previously asymptomatic. The increased sensitivity during pregnancy may be related to physiological, gestational alterations in vitamin D and calcium metabolism and may be influenced by gene variants. The prevalence is unknown. We investigated the prevalence of hypercalcemia in trimester 3 (T3) in a population representative prospective cohort study (n = 1832) in South-West Sweden. Women with serum albumin (Alb) adjusted calcium (Ca_Alb) ≥ 2.65 mmol/L in T3 (n = 30) were matched to normo-calcemic controls, and markers of calcium and vitamin D metabolism were investigated in trimester 1 (T1) and T3. Serum concentrations of Ca, phosphate (P), Magnesium (Mg), Alb and creatinine (Cr), parathyroid hormone (PTH; T3 only), vitamin D metabolites (total 25(OH)D, 1,25(OH)₂D, 24,25(OH)₂D, and free 25(OH)D) were analysed in T1 and T3. Ca_Alb (Payne; inter-laboratory difference: UEA = 0.15 + 0.9*UGOT; UEA 2.54 = UGOT 2.65) and estimated glomerular filtration rate (eGFR; modified 4-variable MDRD) and vitamin D metabolites ratios (VMR) were calculated. Normally and non-normally distributed data were presented as mean (SD) or median (95 %CI). Group differences in relationships between vitamin D metabolites and with PTH were investigated with multiple regression analyses. Hypercalcemia in T3 was found in 1.7 % of women. PTH concentrations suggestive of primary hyperparathyroidism was found in 1 woman and none had 25(OH)D or 24,25(OH)₂D concentrations in the toxicity range or suggestive of mutations in the CYP24A1 gene. Ca_Alb was significantly higher in hypercalcemic cases compared to controls in T1 (2.44 (2.30-2.80) vs 2.37 (2.25-2.49) mmol/L) and T3 (2.63 (2.52-2.78) vs 2.46 (2.31-2.58) mmol/L). Serum P was higher among cases than controls in T3 (1.12 (0.16) vs 1.07 (0.18) mmol/L) but not in T1 (1.12 (0.18) and 1.12 (0.16) mmol/L). PTH in T3 was lower in cases (1.6 (1.6-2.8) vs 2.3 (2.1-2.8) pmol/L) but 1,25(OH)₂D concentrations were similar. There were no significant group differences in serum 25(OH)D, free 25(OH)D, 24,25(OH)₂D, Mg, Alb, Cr and eGFR. Regression analyses did not show significant differences between cases and controls in relationships between vitamin D metabolites and with PTH, except for the free 25(OH)D-PTH relationship and a higher free:total 25(OH)D ratio in cases at T1. In conclusion, most common causes of hypercalcemia were excluded in the majority of women. Hypercalcemic women had a relatively high serum 1,25(OH)₂D concentration despite an appropriately suppressed PTH, suggestive of abnormal gestational adaptions.

Systematic Review and Meta-Analysis of the Effect of Nutrients on Blood Lead Levels in Pregnancy

OBJECTIVE

To synthesize experimental and nonexperimental research on the relationship between nutrients and blood lead levels in pregnant women. We also performed a meta-analysis on a subgroup of studies on calcium and blood lead levels.

DATA SOURCES

PubMed, Embase, and CINAHL databases were searched in July 2019.

STUDY SELECTION

We included articles published in English in any year that reported the results of experimental or observational studies on the effect of nutrients on blood lead levels in pregnancy.

DATA EXTRACTION

Three nurse reviewers extracted data and appraised the studies using tools from the Joanna Briggs Institute.

DATA SYNTHESIS AND META-ANALYSIS

We included 28 studies from 16 countries. Study authors examined 14 distinct nutrients, with calcium being the most frequent. The metaregression included nine analyses of the effect of calcium on blood lead levels and showed a small but significant inverse relationship. The quality of evidence for the effect of calcium on lead levels was high. Eleven analyses were related to the effect of iron on blood lead levels. The quality of evidence was high, and we found mostly negative associations between iron intake and blood lead levels. The quality of evidence for the remaining nutrients was moderate, with few significant findings.

CONCLUSION

Targeted nutritional interventions may be beneficial for pregnant women with current lead exposure or a history of elevated lead levels, particularly those with calcium- or iron-deficient diets. More rigorously designed studies are needed in this area.

Gestational Age and Maternal Serum 25-hydroxyvitamin D Concentration Interact to Affect the 24,25-dihydroxyvitamin D Concentration in Pregnant Adolescents

Background

Interpretation of serum vitamin D biomarkers across pregnancy is complex due to limited understanding of pregnancy adaptations in vitamin D metabolism. During pregnancy, both gestational age and serum 25-hydroxyvitamin D [25(OH)D] concentrations may influence the concentrations of 1,25-dihydroxyvitamin D [1,25(OH)2D], 24,25-dihydroxyvitamin D [24,25(OH)2D], and parathyroid hormone (PTH).

Objective

We aimed to identify predictors of change in serum 25(OH)D across gestation in pregnant adolescents and to assess the contribution made by cholecalciferol (vitamin D3) supplementation. We sought to determine whether gestational age and 25(OH)D concentration interacted to affect serum 1,25(OH)2D, 24,25(OH)2D, or PTH.

Methods

Pregnant adolescents (n = 78, 59% African American, mean ± SD age: 17 ± 1 y) living in Rochester, NY (latitude 43°N) were supplemented with 200 IU or 2000 IU vitamin D3/d and allowed to continue their daily prenatal supplement that contained 400 IU vitamin D3. Serum was collected at study entry (18 ± 5 wk of gestation), halfway through study participation, and at delivery (40 ± 2 wk). Serum concentrations of the biochemical markers were modeled with linear mixed-effects regression models.

Results

Vitamin D3 supplement intake and season of delivery determined change in 25(OH)D across pregnancy. Fall-winter delivery was associated with a decline in 25(OH)D unless vitamin D3 supplement intake was >872 IU/d. The interaction of gestational age and 25(OH)D affected 24,25(OH)2D concentrations. For a given 25(OH)D concentration, model-predicted serum 24,25(OH)2D increased across gestation except when 25(OH)D was <13 ng/mL. Below this threshold, 24,25(OH)2D was predicted to decline over time. Mean serum 1,25(OH)2D was elevated (>100 pg/mL) throughout the study.

Conclusion

Our results suggest that when maternal serum 25(OH)D was low, its catabolism into 24,25(OH)2D decreased or remained stable as pregnancy progressed in order to maintain persistently elevated serum 1,25(OH)2D. Furthermore, in adolescents living at latitude 43°N, standard prenatal supplementation did not prevent a seasonal decline in 25(OH)D during pregnancy. This study was registered at clinicaltrials.gov as NCT01815047.

The relationship between maternal and child bone density in Nigerian children with and without nutritional rickets

We found a positive relationship between bone density in Nigerian children with and without rickets and that of their mothers. After treatment, children with rickets had greater bone density than children without rickets, indicating that children genetically programmed to have greater bone density may have a higher risk of rickets.

INTRODUCTION

To determine the relationship between bone density in children with and without rickets and that of their mothers METHODS: Using an unmatched case-control design, forearm areal bone mineral density (aBMD) was measured in 52 and 135 Nigerian children with and without rickets and their mothers, respectively. We performed multivariate linear regression analyses to assess the relationship between maternal and child aBMD Z-scores.

RESULTS

Forearm aBMD Z-scores in children were associated with maternal aBMD Z-scores at metaphyseal (effect estimate 0.23; 95% CI 0.08 to 0.37) and diaphyseal (effect estimate 0.16; 0.01 to 0.30) sites, after adjustment for rickets in the child, child's age and sex, height-for-age Z-score, and weight-for-age Z-score. In the adjusted model, rickets was inversely associated with child's aBMD Z-score at the diaphyseal site only (- 0.45, - 0.65 to - 0.24). The positive relationship between maternal and child aBMD Z-scores was marginally greater in children with rickets (slope 0.56, r = 0.47) than without rickets (slope 0.19, r = 0.20) at the diaphyseal site only (P = 0.06 for interaction) but not at the metaphyseal site (slopes 0.35 and 0.30, respectively, P = 0.48). After treatment with calcium for 6 months, metaphyseal aBMD Z-scores were greater in children with treated rickets (effect estimate 0.26; 95% CI 0.02 to 0.49) than in those without rickets.

CONCLUSION

In Nigerian children with and without rickets, forearm aBMD Z-scores were positively associated with maternal aBMD Z-scores. Active rickets in the child marginally modified the relationship at the diaphyseal site only. After treatment, children with rickets had greater metaphyseal aBMD Z-scores than children without rickets.

Limitations of the Evidence Base Used to Set Recommended Nutrient Intakes for Infants and Lactating Women

Reported values for concentrations of micronutrients in human milk form the basis of the majority of micronutrient intake recommendations for infants and the additional maternal requirements for lactation. The infant recommendations may also be extrapolated to provide estimates for young children. The purpose of this review is to evaluate the adequacy of the milk micronutrient concentration data used by the Institute of Medicine to set recommendations for the United States and Canada, by FAO/WHO, the United Kingdom, and the European Food Safety Authority. The concentrations accepted by each agency are presented for each micronutrient accompanied by the source of information and comments on the number, location, status, and stage of lactation of the sample population, where known. These summaries show the small number of participants from which samples were collected in most studies, the wide range of concentrations within studies, the lack of longitudinal data, and the variability in collection methods. These factors contribute to the variability in nutrient intake recommendations among committees, although this variability is reduced by some committees that accept milk-composition values proposed by others. Values are also summarized from milk collected in studies in which mothers or infants were known to be deficient on the basis of clinical symptoms, biomarkers of inadequacy, or both, to show the extent to which milk micronutrients can be reduced by poor maternal nutritional status. We conclude that a new, multicenter study is needed to establish reference values for milk constituents across lactation.

Changes in bone turnover and calcium homeostasis during pregnancy and lactation in mammals: a meta-analysis

Large amounts of calcium are required during pregnancy and lactation to support fetal and neonatal bone growth and calcification. An inadequate supply of calcium during these stages can lead to unsuccessful reproduction or impaired offspring fitness. During reproduction, female mammals undergo numerous physiological changes, including adaptations to allow an adequate supply of calcium. The lack of quantitative studies analysing these physiological changes from a comparative perspective limits our ability to explain and understand these adaptations. Herein, we present our meta-analysis of studies reporting changes in bone turnover and calcium homeostasis during pregnancy and lactation in 14 species of mammals. Our meta-analysis of 60 studies showed that all species have a similar pattern of physiological changes during pregnancy and lactation, which include: (1) decreased serum calcium concentrations; (2) bone tissue loss; (3) decreased serum calcitonin and parathyroid hormone concentrations; and (4) increased serum calcitriol concentration, regardless of changes in parathyroid hormone concentrations. In addition, we found a negative relationship between: (1) serum calcium concentrations and the number of teats; and (2) serum parathyroid hormone concentrations and litter mass.

Iron status of North American pregnant women: an update on longitudinal data and gaps in knowledge from the United States and Canada

Pregnant women are particularly vulnerable to iron deficiency due to the high iron demands of pregnancy. To avoid the adverse birth outcomes that are associated with maternal iron deficiency anemia, both Canada and the United States recommend universal iron supplementation for pregnant women. Although the benefits of iron supplementation in anemic women are well recognized, insufficient data are currently available on the maternal and neonatal benefits and harms of universal iron supplementation in developed countries as evidenced by the recent conclusions of the US Preventive Services Task Force on the need for further data that address existing gaps. As part of an effort to evaluate the impact of the current North American prenatal iron supplementation policy, this review highlights the lack of national data on longitudinal changes in iron status in pregnant North American women, emphasizes possible limitations with the original longitudinal hemoglobin data used to inform the current CDC reference hemoglobin values, and presents additional normative data from recent longitudinal research studies of iron status in North American pregnant women. Further longitudinal data in North American pregnant women are needed to help identify those who may benefit most from supplementation as well as to help determine whether there are adverse effects of iron supplementation in iron-replete women.

A case of refeeding syndrome in pregnancy with anorexia nervosa

Refeeding syndrome very rarely develops during pregnancy. A 35-year-old primiparous woman pregnant with twins complained of severe fatigue at 19 weeks' gestation. She was admitted to our hospital in a malnourished condition because of repeated self-induced vomiting due to anorexia nervosa. Just after hospitalization, she voluntarily increased her caloric intake significantly above the recommended prescribed diet, without medical permission. Nine days later, she developed refeeding syndrome. Electrolyte replacement and calorie restriction were started and her condition gradually improved. The healthy twin babies were born by cesarean section at 36 weeks' gestation. Acute increases in caloric intake by previously malnourished pregnant women with anorexia nervosa may induce refeeding syndrome. Women with the binge eating/purging subtype of anorexia nervosa may be at additional risk due to alternating phases of starvation and overeating.

Vitamin D and its impact on maternal-fetal outcomes in pregnancy: A critical review

The role of vitamin D beyond its classical function in calcium homeostasis has been of significant interest in recent years. There has been expanding research on the pleiotropic role of vitamin D in pregnancy and the implications of its deficiency on maternal-fetal outcomes. Several studies have associated low maternal vitamin D status to adverse outcomes in pregnancy, including preeclampsia, gestational diabetes, preterm births, low birth weight, and others. Several randomized controlled clinical trials of Vitamin D supplementation during pregnancy have also been conducted. Though some of the studies found improvement in pregnancy outcomes with vitamin D supplementation, others have not shown any association. In this article, we have critically reviewed the observational and interventional studies, published primarily within the past two years (January 2014 to February 2016) on the influence of vitamin D deficiency on pregnancy and the impact of its supplementation. The potential underlying mechanisms of vitamin D in regulating each of the outcomes have also been discussed.

The relationship of maternal bone density with nutritional rickets in Nigerian children

Factors that affect maternal bone mineral density may be related to the risk of nutritional rickets in their offspring. Our aim was to determine the relationship between maternal areal bone mineral density (aBMD) and rickets in Nigerian children. Using a case-control design, we measured forearm aBMD in 56 and 135 mothers of children with and without nutritional rickets, respectively. Active rickets was confirmed or excluded in all children radiographically. Using logistic regression, we assessed the association of maternal aBMD, adjusted for parity, pregnancy and lactation status, duration of most recent completed lactation, age of menarche, height, body mass index, and maternal age with nutritional rickets. The median (range) age of all mothers was 30years (17-47years), and parity was 4 (1-12). A total of 36 (19%) were pregnant and 55 (29%) were currently breast feeding. Mean (±SD) metaphyseal forearm aBMDs were 0.321±0.057 and 0.316±0.053g/cm² in mothers of children with and without rickets, respectively (P=0.60). Diaphyseal forearm aBMDs were 0.719±0.071 and 0.715±0.072g/cm², respectively (P=0.69). In an adjusted analysis, maternal forearm aBMD, bone mineral content and bone area at metaphyseal and diaphyseal sites were not associated with rickets in the child. In the adjusted analysis, rickets was associated with shorter duration of most recently completed lactation (aOR 0.91 for each additional month; 95% CI 0.83-0.99), older maternal age (aOR 1.07 for each additional year; 1.00-1.14), and less frequent maternal use of lead-containing eye cosmetics (aOR 0.20; 95% CI 0.05-0.64), without any difference in maternal blood lead levels. Maternal age, parity, age of menarche, height, and body mass index were not associated with having had a child with rickets in multivariate analysis. Nutritional rickets in Nigerian children was not associated with maternal forearm aBMD. Other unidentified maternal characteristics and practices likely contribute to the risk of rickets in Nigerian children.

Maternal vitamin D biomarkers are associated with maternal and fetal bone turnover among pregnant women consuming controlled amounts of vitamin D, calcium, and phosphorus

Vitamin D plays a central role in calcium homeostasis; however, its relationship with bone turnover during pregnancy remains unclear due to a lack of studies that have rigorously controlled for vitamin D and other nutrients known to influence bone metabolism. Similarly, prior investigations of the effect of pregnancy on bone turnover relative to the nonpregnant state may have been confounded by varying intakes of these nutrients. Nested within a controlled intake study, the present investigation sought to quantify associations between maternal vitamin D biomarkers and biochemical markers of bone turnover among pregnant (versus nonpregnant) women and their fetuses under conditions of equivalent and adequate intakes of vitamin D and related nutrients. Changes in markers of bone turnover across the third trimester were also examined. Healthy pregnant (26-29 wk gestation; n=26) and nonpregnant (n=21) women consumed 511IU vitamin D/d, 1.6g calcium/d, and 1.9g phosphorus/d for 10weeks while participating in a controlled feeding study featuring two choline doses. Based on linear mixed models adjusted for influential covariates (e.g., BMI, ethnicity, and season), pregnant women had 50-150% higher (P<0.001) concentrations of bone resorption markers than nonpregnant women. Among pregnant women, increases in maternal 25(OH)D across the study period were associated (P<0.020) with lower osteocalcin and deoxypyridinoline at study-end, and higher fetal osteocalcin. In addition, maternal free 25(OH)D, 1,25(OH)₂D and 24,25(OH)₂D tended to be negatively associated (P≤0.063) with maternal NTx at study-end, and maternal free 25(OH)D and 24,25(OH)₂D were positively associated (P≤0.021) with fetal CTx. Similarly, maternal 3-epi-25(OH)D₃ was negatively related (P≤0.037) to maternal NTx and deoxypyridinoline at study-end. These declines in bone resorption markers resulting from higher vitamin D biomarker concentrations among pregnant women coincided with increases in their albumin-corrected serum calcium concentrations, indicating that calcium transfer to the fetus was uncompromised. Notably, none of these associations achieved statistical significance among nonpregnant women. Overall, our study findings suggest that achieving higher maternal concentrations of vitamin D biomarkers might attenuate third-trimester bone resorption while ensuring sufficient calcium delivery to the fetus.

Maternal Diet and Nutrient Requirements in Pregnancy and Breastfeeding. An Italian Consensus Document

The importance of lifestyle and dietary habits during pregnancy and breastfeeding, for health of mothers and their offspring, is widely supported by the most recent scientific literature. The consumption of a varied and balanced diet from the preconceptional period is essential to ensure both maternal well-being and pregnancy outcomes. However, the risk of inadequate intakes of specific micronutrients in pregnancy and lactation is high even in the most industrialized countries. This particularly applies to docosahexaenoic acid (DHA), iron, iodine, calcium, folic acid, and vitamin D, also in the Italian population. Moreover, the risk of not reaching the adequate nutrient supply is increased for selected groups of women of childbearing age: those following exclusion diets, underweight or overweight/obese, smokers, adolescents, mothers who have had multiple or close pregnancies, and those with previous unfavorable pregnancy outcomes.

Increased Calcium Supplementation Postpartum Is Associated with Breastfeeding among Chinese Mothers: Finding from Two Prospective Cohort Studies

The calcium supplementation status during the postpartum period among Chinese lactating women is still unclear. The objective of this study is to utilize data from two population-based prospective cohort studies to examine the calcium supplementation status and to identify whether breastfeeding is associated with increased calcium supplementation among Chinese mothers after child birth. Information from 1540 mothers on breastfeeding and calcium supplementation measured at discharge, 1, 3, and 6 months postpartum were extracted to evaluate the association between breastfeeding and calcium supplementation postpartum. A generalized linear mixed model was applied to each study initially to account for the inherent correlation among repeated measurements, adjusting for socio-demographic, obstetric factors and calcium supplementation during pregnancy. In addition, breastfeeding status measured at different follow-up time points was treated as a time dependent variable in the longitudinal analysis. Furthermore, the effect sizes of the two cohort studies were pooled using fixed effect model. Based on the two cohort studies, the pooled likelihood of taking calcium supplementation postpartum among breastfeeding mothers was 4.02 times (95% confidence interval (2.30, 7.03)) higher than that of their non-breastfeeding counterparts. Dietary supplementation intervention programs targeting different subgroups should be promoted in Chinese women, given currently a wide shortage of dietary calcium intake and calcium supplementation postpartum.

The Calcium-Sensing Receptor and the Reproductive System

Active placental transport of maternal serum calcium (Ca²⁺) to the offspring is pivotal for proper development of the fetal skeleton as well as various organ systems. Moreover, extracellular Ca²⁺ levels impact on distinct processes in mammalian reproduction. The calcium-sensing receptor (CaSR) translates changes in extracellular Ca²⁺-concentrations into cellular reactions. This review summarizes current knowledge on the expression of CaSR and its putative functions in reproductive organs. CaSR was detected in placental cells mediating materno-fetal Ca²⁺-transport such as the murine intraplacental yolk sac (IPYS) and the human syncytiotrophoblast. As shown in casr knock-out mice, ablation of CaSR downregulates transplacental Ca²⁺-transport. Receptor expression was reported in human and rat ovarian surface epithelial (ROSE) cells, where CaSR activation stimulates cell proliferation. In follicles of various species a role of CaSR activation in oocyte maturation was suggested. Based on studies in avian follicles, the activation of CaSR expressed in granulosa cells may support the survival of follicles after their selection. CaSR in rat and equine sperms was functionally linked to sperm motility and sperm capacitation. Implantation involves complex interactions between the blastocyst and the uterine epithelium. During early pregnancy, CaSR expression at the implantation site as well as in decidual cells indicates that CaSR is important for blastocyst implantation and decidualization in the rat uterus. Localization of CaSR in human extravillous cytotrophoblasts suggests a role of CaSR in placentation. Overall, evidence for functional involvement of CaSR in physiologic mammalian reproductive processes exists. Moreover, several studies reported altered expression of CaSR in cells of reproductive tissues under pathologic conditions. However, in many tissues we still lack knowledge on physiological ligands activating CaSR, CaSR-linked G-proteins, activated intracellular signaling pathway, and functional relevance of CaSR activation. Clearly, more work is required in the future to decode the complex physiologic and pathophysiologic relationship of CaSR and the mammalian reproductive system.

Calcium plus vitamin D supplementation during pregnancy interacts with polymorphisms in the promoter region of the VDR gene to affect postpartum bone mass of Brazilian adolescent mothers: A randomized controlled trial

OBJECTIVE

We investigated whether calcium plus vitamin D supplementation interacts with polymorphisms in the VDR gene promoter region to affect changes on maternal bone mass from 5 to 20 wk postpartum in Brazilian adolescent mothers.

METHODS

Pregnant adolescents (14-19 y) randomly received calcium plus cholecalciferol (600 mg/d + 200 IU/d, n = 30) or placebo (n = 26) from 26 wk of pregnancy until parturition. Bone mineral content (BMC), bone area (BA), and bone mineral density (BMD) at total body, lumbar spine, total hip, and femoral neck were evaluated at 5 and 20 wk postpartum. Serum 25-hydroxyvitamin D (25[OH]D) and parathyroid hormone concentrations were measured. Real-time polymerase chain reaction was used for genotyping rs7139166 (1521 pb G > C) and rs4516035 (1012 pb A > G). Interactions between supplementation and polymorphisms were adjusted for significant covariates.

RESULTS

Changes in serum 25(OH)D from pregnancy to postpartum differed between supplemented and placebo groups for mothers carrying 1521 GG/1012 AA genotypes (P = 0.004). Only in the placebo group, mothers carrying 1521 GG/1012 AA had greater reduction in total BMD z score, femoral neck BMC, and BMD from 5 to 20 wk postpartum compared with those with 1521 GC/1012 AG (P < 0.05). In the placebo group, total hip BA decreased from 5 to 20 wk postpartum in adolescents with 1521 GG/1012 AA, but increased in those with 1521 GC/1012 AG (P < 0.05), in contrast to the supplemented group.

CONCLUSION

Calcium plus vitamin D supplementation during pregnancy interacted with polymorphisms in the VDR gene promoter region affecting postpartum bone loss. The increased supply of calcium and vitamin D appeared to minimize postpartum bone loss particularly in adolescents with 1521 GG/1012 AA.

Rankings of iron, vitamin D, and calcium intakes in relation to maternal characteristics of pregnant Canadian women

Iron, vitamin D, and calcium intakes in the prenatal period are important determinants of maternal and fetal health. The objective of this study was to examine iron, vitamin D, and calcium intakes from diet and supplements in relation to maternal characteristics. Data were collected in a subsample of 1186 pregnant women from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a cohort study including pregnant women recruited from 10 Canadian sites between 2008 and 2011. A food frequency questionnaire was administered to obtain rankings of iron, calcium, and vitamin D intake (16-21 weeks of pregnancy). Intakes from supplements were obtained from a separate questionnaire (6-13 weeks of pregnancy). Women were divided into 2 groups according to the median total intake of each nutrient. Supplement intake was an important contributor to total iron intake (median 74%, interquartile range (IQR) 0%-81%) and total vitamin D intake (median 60%, IQR 0%-73%), while the opposite was observed for calcium (median 18%, IQR 0%-27%). Being born outside of Canada was significantly associated with lower total intakes of iron, vitamin D, and calcium (p ≤ 0.01 for all). Consistent positive indicators of supplement use (iron, vitamin D, and calcium) were maternal age over 30 years and holding a university degree. In conclusion, among Canadian women, the probability of having lower iron, vitamin D, and calcium intakes is higher among those born outside Canada; supplement intake is a major contributor to total iron and vitamin D intakes; and higher education level and age over 30 years are associated with supplement intake.

Effects of Dairy Products Consumption on Health: Benefits and Beliefs--A Commentary from the Belgian Bone Club and the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases

Dairy products provide a package of essential nutrients that is difficult to obtain in low-dairy or dairy-free diets, and for many people it is not possible to achieve recommended daily calcium intakes with a dairy-free diet. Despite the established benefits for bone health, some people avoid dairy in their diet due to beliefs that dairy may be detrimental to health, especially in those with weight management issues, lactose intolerance, osteoarthritis, rheumatoid arthritis, or trying to avoid cardiovascular disease. This review provides information for health professionals to enable them to help their patients make informed decisions about consuming dairy products as part of a balanced diet. There may be a weak association between dairy consumption and a possible small weight reduction, with decreases in fat mass and waist circumference and increases in lean body mass. Lactose intolerant individuals may not need to completely eliminate dairy products from their diet, as both yogurt and hard cheese are well tolerated. Among people with arthritis, there is no evidence for a benefit to avoid dairy consumption. Dairy products do not increase the risk of cardiovascular disease, particularly if low fat. Intake of up to three servings of dairy products per day appears to be safe and may confer a favourable benefit with regard to bone health.

The effects of different levels of calcium supplementation on the bone mineral status of postpartum lactating Chinese women: a 12-month randomised, double-blinded, controlled trial

Increasing dietary Ca intake may prevent the excessive mobilisation of bone mineral in nursing mothers. We aimed to investigate whether higher Ca intake could positively modulate the bone mineral changes in Chinese postpartum lactating women. The study was a 12-month randomised, double-blinded, parallel group trial conducted over 12 months. A total of 150 postpartum women were randomly selected to receive either 40 g of milk powder containing 300 mg of Ca and 5 μg of vitamin D (Low-Ca group) or same milk powder additionally fortified with 300 mg of Ca (Mid-Ca group) or 600 mg of Ca (High-Ca group). Bone mineral density (BMD) for the whole body, the lumbar spine, the total left hip and its sub-regions was measured using dual-energy X-ray absorptiometry. A total of 102 subjects completed the whole trial. The duration of total lactating time was 7·9 (sd 2·8) months on average. The intention-to-treat analysis yielded the following mean percentage changes in BMD for the whole body, the lumbar spine and the total left hip, respectively: −0·93 (sd 1·97), 2·11 (sd 4·90) and −1·60 (sd 2·65) % for the Low-Ca group; −0·56 (sd 1·89), 2·21 (sd 3·77) and −1·43 (sd 2·30) % for the Mid-Ca group; and −0·44 (sd 1·67), 2·32 (sd 4·66) and −0·95 (sd 4·08) % for the High-Ca group. The differences between the groups were not statistically significant (P: 0·5–0·9). The results of the complete case analysis were similar. In sum, we found no significant differences in the bone mineral changes from baseline to 12 months in postpartum lactating women consuming milk powder fortified with different levels of Ca.

Calcium Plus Vitamin D Supplementation During the Third Trimester of Pregnancy in Adolescents Accustomed to Low Calcium Diets Does Not Affect Infant Bone Mass at Early Lactation in a Randomized Controlled Trial

BACKGROUND

Pregnancy and lactation in adolescents with low calcium intake may impair fetal growth and infant bone mass.

OBJECTIVE

We investigated the effects of calcium plus vitamin D supplementation during pregnancy in Brazilian adolescent mothers consuming low calcium diets (∼600 mg/d) on fetal biometry and infant bone mass, and the relation between infant and maternal bone mass during early lactation.

METHODS

Infants of mothers who received calcium (600 mg/d) plus cholecalciferol (200 IU/d) supplementation (n = 30) or placebo (n = 26) from 26 wk of gestation until parturition were studied. Fetal biometric measurements at 23 and 36 wk of gestation were obtained from medical records. Infant anthropometric and total body bone measurements [bone mineral content (BMC), bone area (BA), and bone mineral density (BMD)] at 5 wk postpartum were assessed by dual-energy X-ray absorptiometry. Maternal BMD z scores for total body, lumbar spine, total hip, and femoral neck at 5 wk postpartum were obtained. Group comparisons were adjusted for significant covariates.

RESULTS

Maternal mean serum 25-hydroxyvitamin D was 59 nmol/L at baseline in both groups. No differences in fetal measurements at 36 wk of gestation were observed between the groups, except for body weight and its increment from 23 to 36 wk, which were higher in the supplemented group (6.8%, P = 0.014 and 10.5%, P = 0.07, respectively). Infant BMC (61.1 ± 21.7 g), BA (167 ± 79 cm(2)), and BMD (0.385 ± 0.069 g/cm(2)) did not significantly differ between the groups. In the placebo group, infant BMC and BA were negatively correlated with maternal BMD z scores for total body (r = -0.40 and r = -0.47; P < 0.05) and hip (r = -0.41 and r = -0.46; P < 0.05). In contrast, no correlations were observed in the supplemented group.

CONCLUSIONS

Calcium and vitamin D supplementation of the adolescents studied resulted in higher fetal body weight at 36 wk of gestation and had no effect on infant bone mass at 5 wk postpartum. Because correlations between maternal and infant bone mass were evident only in the placebo group, infant bone mass appeared to be more dependent on maternal skeletal mass when calcium intake was low. This trial was registered at clinicaltrials.gov as NCT01732328.

Changes in cortical volumetric bone mineral density and thickness, and trabecular thickness in lactating women postpartum

CONTEXT

Lactation is associated with decreased areal bone mineral density (aBMD). Replenishment occurs especially after ceased lactation. Changes in volumetric bone mineral density (vBMD), microstructure, and dimensional parameters are unknown and may clarify the role of lactation for skeletal health. OBJECTIVE AND MAIN OUTCOMES: The objective of the study was to test the hypothesis that lactation is associated with changes in aBMD, vBMD, microstructure, and dimensional parameters.

DESIGN

At baseline (0.5 mo after delivery) and 4, 12, and 18 months thereafter, bone was assessed using dual-energy x-ray absorptiometry and high-resolution peripheral quantitative computed tomography.

PARTICIPANTS AND SETTING

Eighty-one fair-skinned postpartum women and 21 controls aged 25-40 years were recruited. The completion ratio was 73%. Postpartum women were categorized depending on duration of lactation: 0-3.9, 4-8.9, and 9 months or longer.

RESULTS

During the first 4 months, aBMD decreased at several sites (geometric mean ± SE; -0.73% ± 0.21% to -3.98% ± 0.76%) in women lactating at least 4 months. During the same time, cortical vBMD at the ultradistal tibia decreased in women lactating 4-8.9 months (-0.26% ± 0.08%) and 9 months or longer (-0.49% ± 0.10%). At 12 months postpartum, cortical thickness (≥ 9 mo, -2.48% ± 0.41%) and trabecular thickness (4-8.9 mo, -2.14% ± 0.92%; ≥ 9 mo, -2.56% ± 1.21%) also were lower than baseline. No decreases were found in women lactating less than 4 months or in controls in these parameters. At 18 months postpartum, both cortical vBMD (≥ 9 mo, -0.77% ± 0.17%) and trabecular thickness (4-8.9 mo, -2.25% ± 1.25%; ≥ 9 mo, -3.21% ± 1.41%) were lower in women with long lactation.

CONCLUSIONS

Decreases in cortical vBMD, thickness, and trabecular thickness at the ultradistal tibia were found in women lactating 4 months or longer. Longer follow-up is needed to confirm whether women with extended lactation recover fully or whether the changes could potentially lead to an increased risk of fracture in later life.