Maternal hypomagnesemia causes placental abnormalities and fetal and postnatal mortality

Gene-nutrient interactions that impact magnesium homeostasis increase risk for neural tube defects in mice exposed to dolutegravir

In 2018, data from a surveillance study in Botswana evaluating adverse birth outcomes raised concerns that women on antiretroviral therapy (ART) containing dolutegravir (DTG) may be at increased risk for neural tube defects (NTDs). The mechanism of action for DTG involves chelation of Mg2+ ions in the active site of the viral integrase. Plasma Mg2+ homeostasis is maintained primarily through dietary intake and reabsorption in the kidneys. Inadequate dietary Mg2+ intake over several months results in slow depletion of plasma Mg2+ and chronic latent hypomagnesemia, a condition prevalent in women of reproductive age worldwide. Mg2+ is critical for normal embryonic development and neural tube closure. We hypothesized that DTG therapy might slowly deplete plasma Mg2+ and reduce the amount available to the embryo, and that mice with pre-existing hypomagnesemia due to genetic variation and/or dietary Mg2+ insufficiency at the time of conception and initiation of DTG treatment would be at increased risk for NTDs. We used two different approaches to test our hypothesis: 1) we selected mouse strains that had inherently different basal plasma Mg2+ levels and 2) placed mice on diets with different concentrations of Mg2+. Plasma and urine Mg2+ were determined prior to timed mating. Pregnant mice were treated daily with vehicle or DTG beginning on the day of conception and embryos examined for NTDs on gestational day 9.5. Plasma DTG was measured for pharmacokinetic analysis. Our results demonstrate that hypomagnesemia prior to conception, due to genetic variation and/or insufficient dietary Mg2+ intake, increases the risk for NTDs in mice exposed to DTG. We also analyzed whole-exome sequencing data from inbred mouse strains and identified 9 predicted deleterious missense variants in Fam111a that were unique to the LM/Bc strain. Human FAM111A variants are associated with hypomagnesemia and renal Mg2+ wasting. The LM/Bc strain exhibits this same phenotype and was the strain most susceptible to DTG-NTDs. Our results suggest that monitoring plasma Mg2+ levels in patients on ART regimens that include DTG, identifying other risk factors that impact Mg2+ homeostasis, and correcting deficiencies in this micronutrient might provide an effective strategy for mitigating NTD risk.

Calcium, Potassium, Sodium, and Magnesium Concentrations in the Placenta, Umbilical Cord, and Fetal Membrane from Women with Multiple Pregnancies

Calcium (Ca), potassium (K), sodium (Na), and magnesium (Mg) are the elements responsible for the fundamental metabolic and biochemical processes in the cells of the body. The demand for these elements increases significantly during pregnancy, where an adequate supply protects women from the hypertension common in pre-eclampsia and preterm labor. This study aimed to evaluate the association between macro-elements (Ca, Mg, Na, and K) in the placenta, fetal membrane, and umbilical cord and the morphometric parameters of newborns from multiple pregnancies. The study involved 57 pregnant European women with healthy uncomplicated twin pregnancies (n = 52) and triple pregnancies (n = 5); 40 pairs of dichorionic diamniotic twins, 11 pairs of monochorionic diamniotic twins, 1 pair of monochorionic monoamniotic twins, 3 trichorionic triamniotic triplets, and 2 dichorionic triamniotic triplets. Placentas (n = 107), umbilical cords (n = 114), and fetal membranes (n = 112) were collected immediately following delivery, and then weighed and measured. The levels of Ca, K, Na, and Mg were determined using inductively coupled plasma atomic emission spectroscopy (ICP-OES) in a Thermo Scientific ICAP 7400 Duo (Waltham, MA, USA). The respective mean concentrations of Ca, K, Na, and Mg (mg/kg^-1 dry mass) were: 2466, 8873, 9323, and 436 in the placenta; 957, 6173, 26,757, and 326 in the umbilical cord, and 1252, 7460, 13,562, and 370 in the fetal membrane. In the studied materials from northwestern Poland, we found strong positive correlations between Ca and Mg concentrations in both the umbilical cord (r = 0.81, p = 0.00) and the fetal membrane (r = 0.73, p = 0.00); between K and Mg concentrations in the umbilical cord (r = 0.73, p = 0.00); between Ca and K concentrations in the fetal membrane (r = 0.73, p = 0.00), and we found moderately positive correlations between placental Ca concentration and placental weight (ρ = 0.42, p = 0.00) and between umbilical cord Mg concentrations and the length of the pregnancy (ρ = 0.42, p = 0.00). Negative correlations were found between Na and Ca concentrations in the fetal membrane (r = -0.40, p = 0.00) and Na concentrations in the fetal membrane and Mg concentrations in the placenta (r = -0.16, p = 0.02). Negative correlations were confirmed between the length of pregnancy and head circumference (ρ = -0.42; p = 0.00), infant weight (ρ = -0.42; p = 0.00), infant length (ρ = -0.49; p = 0.00), shoulder width (ρ = -0.49; p = 0.00); and between the infant weight and head circumference (ρ = -0.62; p = 0.00), weight before delivery (ρ = -0.36; p = 0.00), infant length (ρ = -0.45; p = 0.00), shoulder width (ρ = -0.63; p = 0.00), and weight gain during pregnancy (ρ = -0.31; p = 0.01). We found statistically significant correlations between cigarette smoking before pregnancy and the women's weight before delivery (ρ = 0.32, p = 0.00), and a negative correlation between the women's ages and infant head circumference (ρ = -0.20, p = 0.02). This is probably the first study to evaluate Ca, Na, K, and Mg concentrations in the afterbirth tissues of multiple pregnancies. It adds to the knowledge of elemental concentrations in multiple pregnancies and their possible effects on fetal morphometric parameters.

PREGNANCY DURING A PANDEMIC: PERINATAL EFFECTS OF PROLONGED STRESS AND WAYS OF CORRECTION (LITERATURE REVIEW)

Relevance: The article presents current evidence on the perinatal effects of prolonged stress on pregnancy during the COVID-19 pandemic.The currently known features of the post-covidsyndrome in general and in the female population in particular are indicated. The purposewas to determine the perinatal effects of prolonged stress during a pandemic and ways to correct them. Materials and method sincludedan analysis of the scientific literature on the topic available in the public domain. Results: The article reviews the peculiarities of the course of pregnancy and perinatal outcomes after suffering a coronavirus infection, as well as the manifestations of post-covid syndrome in this cohort of women. An increase in the frequency of anxiety-depressive disorders in pregnant women and women in labor during a pandemic and their effect on the further mental state of the fetus and the development of its brain has been noted. The specific consequences of prolonged stress were determined.It became known that pregnant women during a pandemic are exposed to prolonged stress, which affects the course of their gestational period. One should note an increase in the frequency of the threat of termination of pregnancy, premature birth and delivery in 17-28% cases; exacerbation of chronic somatic diseases during pregnancy; an increase in BMI on the eve of pregnancy and a pathological increase in body weight during pregnancy. The article also discusses the timely detection and possible ways to correct these conditions despite a transition to remote monitoring of pregnant women in quarantine; offers organizational, treatment, and preventive measures with the use of preparations of micronized progesterone, magnesium citrate, folates (metafoline) and vitamin D, as well as psychoprophylaxis and psychotherapy methods. Particular attention is paid to the role of magnesium in pregnancy and its neuroprotective and metabolic effects, in particular when used in the form of citrate in a soluble form. The authors state the main directions of rehabilitation for pregnant women and women in labor after suffering COVID-19. Conclusion: So, our current knowledge about the course and consequences of COVID-19 in pregnant women and women in childbirth is not yet perfect and not final, but it allows determining the directions of scientific and practical research for the next period.

Evaluation of Fetal Exposures to Metals and Metalloids through Meconium Analyses: A Review

This paper surveys the existing scientific literature on metals concentrations in meconium. We examine some 32 papers that analyzed meconium for aluminum, arsenic, barium, calcium, chromium, copper, iron, lithium, magnesium, manganese, zinc, lead, mercury, manganese, molybdenum, nickel, phosphorus, lead, antimony, selenium, tin, vanadium, and zinc. Because of the lack of detail in the statistics it is not possible to do a rigorous meta-analysis. What stands out is that almost every study had subjects with seemingly large amounts of at least one of the metals. The significance of metals in meconium is not clear beyond an indication of exposure although some studies have correlated metals in meconium to a number of adverse outcomes. A number of outstanding questions have been identified that, if resolved, would greatly increase the utility of meconium analysis for assessment of long-term gestational metals exposures. Among these are questions of the developmental and long-term significance of metals detected in meconium, the kinetics and interactions among metals in maternal and fetal compartments and questions on best methods for meconium analyses.

The prevalence of serum magnesium and iron deficiency anaemia among Sudanese women in early pregnancy: a cross-sectional study

Background

Anaemia during pregnancy is associated with adverse maternal and child health. Investigations of anaemia and its predictors among pregnant women are needed for preventive measures.

Methods

A cross-sectional study was conducted to investigate the prevalence and determinants of anaemia in early pregnancy in Khartoum, Sudan. Clinical characteristics were gathered using a questionnaire. Serum ferritin, magnesium and high-sensitivity C-reactive protein (hs-CRP) were measured using different laboratory methods.

Results

Of the 180 women in the study, 65.0% had anaemia (haemoglobin [Hb] <11 g/dl), 0.6% had severe anaemia (Hb <7 g/dl), 38.9% had iron deficiency (serum ferritin <15 μg/l), 30.6% had iron deficiency anaemia (<11 g/dl and serum ferritin <15 μg/l) and 57.2% had magnesium deficiency (<1.80 mg/dl). There was no significant difference in the age, parity, gestational age, body mass index (BMI) and hs-CRP between anaemic and non-anaemic pregnant women. Anaemic pregnant women had significantly lower levels of serum ferritin and serum magnesium. While age, parity, gestational age, BMI and hs-CRP were not associated with anaemia, low serum ferritin (odds ratio [OR] 0.97 [95% confidence interval {CI} 0.96 to 0.99]) and low serum magnesium (OR 0.91 [95% CI 0.84 to 0.99]) were associated with anaemia. There were significant positive correlations between Hb and serum ferritin (r=0.382, p<0.001) and serum magnesium (r=0.192, p=0.010).

Conclusion

The role of magnesium as a possible contributing factor to anaemia in pregnancy has important implications for prevention and treatment of these women.

Advanced maternal age compromises fetal growth and induces sex-specific changes in placental phenotype in rats

Advanced maternal age is associated with an increased risk of pregnancy complications. It programmes sex-specific cardiovascular dysfunction in rat offspring, however the intrauterine mechanisms involved remain unknown. This study in the rat assessed the impact of advanced maternal age on placental phenotype in relation to the growth of female and male fetuses. We show that relative to young (3-4 months) dams, advanced maternal age (9.5-10 months) compromises growth of both female and male fetuses but affects the placental phenotype sex-specifically. In placentas from aged versus young dams, the size of the placental transport and endocrine zones were increased and expression of Igf2 (+41%) and placental lactogen (Prl3b1: +59%) genes were upregulated in female, but not male fetuses. Placental abundance of IGF2 protein also decreased in the placenta of males only (-95%). Moreover, in placentas from aged versus young dams, glucocorticoid metabolism (11β-hsd2: +63% and 11β-hsd1: -33%) was higher in females, but lower in males (11β-hsd2: -50% and 11β-hsd1: unaltered). There was however, no change in the placental abundance of 11β-HSD2 protein in aged versus young dams regardless of fetal sex. Levels of oxidative stress in the placenta were increased in female and male fetuses (+57% and +90%, respectively) and apoptosis increased specifically in the placenta of males from aged rat dams (+700%). Thus, advanced maternal age alters placental phenotype in a sex-specific fashion. These sexually-divergent changes may play a role in determining health outcomes of female and male offspring of aged mothers.

Biomarkers of oxidative stress in pregnant women with recurrent miscarriages

Background

The aim of this study was to evaluate the markers of oxidative stress (OS), as well as the magnesium (Mg) concentration, pregnancy-associated plasma protein A (PAPP-A) and human chorionic gonadotropin (β-hCG) values in patients with previous recurrent miscarriages, with the purpose of comparing the level of OS with normal pregnancy.

Methods

The study was conducted as a prospective study, which included a total of 95 pregnant women divided into two groups. In the study group (n = 35), there were women with at least three consecutive previous miscarriages. The control group (n = 60) consisted of healthy pregnant women without previous miscarriages and complications in pregnancy. Blood samples were taken between the 11th and 14th weeks of gestation, and the values of superoxide dismutase (SOD-1), glutathione peroxidase (GSH-Px) and total antioxidant status (TAS) in the serum, as well as the Mg concentration, PAPP-A and β-hCG values were determined.

Results

The values of SOD and GHS-Px were statistically higher in the study group, while the values of TAS were statistically significantly higher in the control group. The values of the Mg concentration were statistically significantly higher in the control group, while the values of β-hCG were statistically significantly higher in the study group. When the study group was divided into subgroups according to the outcome of pregnancy, there were statistical differences in the level of GSH-Px, SOD between miscarriages and the term delivery group, as well as in the Mg concentration between miscarriages and the term delivery group and between the term and preterm delivery groups. Higher values of SOD and GHS-Px, and lower values of TAS and Mg concentration could be used as markers for the prediction of spontaneous miscarriages.

Conclusions

The results of this research indicated higher OS and exhaustion of antioxidant mechanisms in early pregnancy in a group with recurrent miscarriages. Also, lower values of serum Mg concentration could be one of the markers for the prediction of spontaneous miscarriages.

Associations between the Level of Trace Elements and Minerals and Folate in Maternal Serum and Amniotic Fluid and Congenital Abnormalities

Congenital birth defects may result in a critical condition affecting the baby, including severe fetal/neonatal handicap and mortality. Several studies have shown that genetic, nutritional, and environmental factors may have an impact on fetal development and neonatal health. The relevance of essential and toxic elements on fetal development has not yet been fully investigated, and the results of recent research indicate that these elements may be crucial in the assessment of the risk of malformations in neonates. We determined the association between essential and toxic elements and the level of folate in maternal serum (MS) and amniotic fluid (AF), along with neonatal abnormalities. A total of 258 pregnant Polish women in the age group of 17⁻42 years participated in this study. AF and MS were collected during vaginal delivery or during cesarean section. An inductively coupled plasma mass spectrometry technique was used to determine the levels of various elements in AF and MS. The results of this exploratory study indicate that the levels of essential and toxic elements are associated with fetal and newborn anatomical abnormalities and growth disorders.

Rural and urban differences in prenatal exposure to essential and toxic elements

Excess or inadequate levels of inorganic ions may induce significant acute and long-term irreversible dysfunction in humans. The fetus and placenta are particularly vulnerable to toxins due to the immaturity of the blood-brain barrier and diminished biotransformation enzymatic activity. A comparative cross-sectional study was conducted on 172 pregnant women, 79 rural, and 93 urban. Umbilical cord blood was collected at the time of delivery and analyzed for 20 inorganic elements. Significant differences were found between urban and rural samples for two elements where copper (Cu) and molybdenum (Mo) were higher in urban samples. No marked differences between groups occurred for: arsenic, barium, cadmium, calcium, cobalt, lead, lithium, magnesium, manganese, mercury, selenium, strontium, or zinc. All samples were devoid of platinum, silver, thallium or uranium. Data demonstrated significant differences in urban and rural prenatal exposure to Cu and Mo. Further study is needed to determine if there is a causal link between neonatal outcomes and prenatal exposure to these elements.

Reduced Uteroplacental Perfusion Pressure (RUPP) causes altered trophoblast differentiation and pericyte reduction in the mouse placenta labyrinth

This study characterized the effect of the reduced utero-placental perfusion pressure (RUPP) model of placental insufficiency on placental morphology and trophoblast differentiation at mid-late gestation (E14.5). Altered trophoblast proliferation, reduced syncytiotrophoblast gene expression, increased numbers of sinusoidal trophoblast giant cells, decreased Vegfa and decreased pericyte presence in the labyrinth were observed in addition to changes in maternal blood spaces, the fetal capillary network and reduced fetal weight. Further, the junctional zone was characterized by reduced spongiotrophoblast and glycogen trophoblast with increased trophoblast giant cells. Increased Hif-1α and TGF-β-3 in vivo with supporting hypoxia studies in trophoblast stem (TS) cells in vitro, support hypoxia as a contributing factor to the RUPP placenta phenotype. Together, this study identifies altered cell populations within the placenta that may contribute to the phenotype, and thus support the use of RUPP in the mouse as a model of placenta insufficiency. As such, this model in the mouse provides a valuable tool for understanding the phenotypes resulting from genetic manipulation of isolated cell populations to further understand the etiology of placenta insufficiency and fetal growth restriction. Further this study identifies a novel relationship between placental insufficiency and pericyte depletion in the labyrinth layer.

Hypomagnesaemia and pregnancy

Hypomagnesaemia is common in pregnancy, particularly in developing countries and low-income communities. Despite the frequent therapeutic use of magnesium in pregnancy, and the evidence regarding the association of hypomagnesaemia with adverse pregnancy outcomes in animal studies, it remains unclear whether hypomagnesaemia is associated with complications in human pregnancy. Three case reports of pregnancies complicated by moderate-severe hypomagnesaemia are presented and magnesium physiology in pregnancy is discussed. The evidence as to whether hypomagnesaemia may represent a direct cause, a consequence of other disease processes or an epiphenomenon in adverse pregnancies outcomes is reviewed.

Placental adaptations to micronutrient dysregulation in the programming of chronic disease

Poor nutrition during pregnancy is known to impair foetal development and increase the risk of chronic disease in offspring. Both macronutrients and micronutrients are required for a healthy pregnancy although significantly less is understood about the role of micronutrients in the programming of chronic disease. This is despite the fact that modern calorie rich diets are often also deficient in key micronutrients. The importance of micronutrients in gestational disorders is clearly understood but how they impact long term disease in humans requires further investigation. In contrast, animal studies have demonstrated how diets high or low in specific micronutrients influence offspring physiology. Many of these studies highlight the importance of the placenta in determining disease risk. This review will explore the effects of individual vitamins, minerals and trace elements on offspring disease outcomes and discuss several key placental adaptations that are affected by multiple micronutrients. These placental adaptations include micronutrient induced dysregulation of oxidative stress, altered methyl donor availability and its impact on epigenetic mechanisms as well as endocrine dysfunction. Critical gaps in our current knowledge and the relative importance of different micronutrients at different gestational ages will also be highlighted. Finally, this review will discuss the need for further studies to characterise the micronutrient status of Australian women of reproductive age and correlate micronutrient status to placental adaptations, pregnancy complications and offspring disease.

Genetic causes of hypomagnesemia, a clinical overview

Magnesium is essential to the proper functioning of numerous cellular processes. Magnesium ion (Mg2+) deficits, as reflected in hypomagnesemia, can cause neuromuscular irritability, seizures and cardiac arrhythmias. With normal Mg2+ intake, homeostasis is maintained primarily through the regulated reabsorption of Mg2+ by the thick ascending limb of Henle's loop and distal convoluted tubule of the kidney. Inadequate reabsorption results in renal Mg2+ wasting, as evidenced by an inappropriately high fractional Mg2+ excretion. Familial renal Mg2+ wasting is suggestive of a genetic cause, and subsequent studies in these hypomagnesemic families have revealed over a dozen genes directly or indirectly involved in Mg2+ transport. Those can be classified into four groups: hypercalciuric hypomagnesemias (encompassing mutations in CLDN16, CLDN19, CASR, CLCNKB), Gitelman-like hypomagnesemias (CLCNKB, SLC12A3, BSND, KCNJ10, FYXD2, HNF1B, PCBD1), mitochondrial hypomagnesemias (SARS2, MT-TI, Kearns-Sayre syndrome) and other hypomagnesemias (TRPM6, CNMM2, EGF, EGFR, KCNA1, FAM111A). Although identification of these genes has not yet changed treatment, which remains Mg2+ supplementation, it has contributed enormously to our understanding of Mg2+ transport and renal function. In this review, we discuss general mechanisms and symptoms of genetic causes of hypomagnesemia as well as the specific molecular mechanisms and clinical phenotypes associated with each syndrome.

Maternal hypomagnesemia alters hippocampal NMDAR subunit expression and programs anxiety-like behaviour in adult offspring

It is well established that maternal undernutrition and micronutrient deficiencies can lead to altered development and behaviour in offspring. However, few studies have explored the implications of maternal Mg deficiency and programmed behavioural and neurological outcomes in offspring. We used a model of Mg deficiency (prior to and during pregnancy and lactation) in CD1 mice to investigate if maternal Mg deficiency programmed changes in behaviour and NMDAR subunit expression in offspring. Hippocampal tissue was collected at postnatal day 2 (PN2), PN8, PN21 and 6 months, and protein expression of NMDAR subunits GluN1, GluN2A and GluN2B was determined. At 6 months of age, offspring were subject to behavioural tasks testing aspects of anxiety-like behaviour, memory, and neophobia. Maternal hypomagnesemia was associated with increased GluN1, GluN2A and GluN2B subunit expression in female offspring at 6 months, but decreased GluN1 and GluN2A expression in males. The GluN2B:GluN2A expression ratio was increased in both sexes. Male (but not female) offspring from Mg-deficient dams showed anxiety-like behaviour, with reduced head dips (Suok test), and reduced exploration of open arms (elevated plus maze). Both male and female offspring from Mg-deficient dams also showed impaired recognition memory (novel object test). These findings suggest that maternal Mg deficiency can result in behavioural deficits in adult life, and that these changes may be related to alterations in hippocampal NMDA receptor expression.

Review: Alterations in placental glycogen deposition in complicated pregnancies: Current preclinical and clinical evidence

Normal placental function is essential for optimal fetal growth. Transport of glucose from mother to fetus is critical for fetal nutrient demands and can be stored in the placenta as glycogen. However, the function of this glycogen deposition remains a matter of debate: It could be a source of fuel for the placenta itself or a storage reservoir for later use by the fetus in times of need. While the significance of placental glycogen remains elusive, mounting evidence indicates that altered glycogen metabolism and/or deposition accompanies many pregnancy complications that adversely affect fetal development. This review will summarize histological, biochemical and molecular evidence that glycogen accumulates in a) placentas from a variety of experimental rodent models of perturbed pregnancy, including maternal alcohol exposure, glucocorticoid exposure, dietary deficiencies and hypoxia and b) placentas from human pregnancies with complications including preeclampsia, gestational diabetes mellitus and intrauterine growth restriction (IUGR). These pregnancies typically result in altered fetal growth, developmental abnormalities and/or disease outcomes in offspring. Collectively, this evidence suggests that changes in placental glycogen deposition is a common feature of pregnancy complications, particularly those associated with altered fetal growth.

Review: Sexual dimorphism in the formation, function and adaptation of the placenta

Exposure of the embryo or fetus to perturbations in utero can result in intrauterine growth restriction, a primary risk factor for the development of adult disease. However, despite similar exposures, males and females often have altered disease susceptibility or progression from different stages of life. Fetal growth is largely mediated by the placenta, which, like the fetus is genetically XX or XY. The placenta and its associated trophoblast lineages originate from the trophectoderm (TE) of the early embryo. Rodent models (rat, mouse, spiny mouse), have been used extensively to examine placenta development and these have demonstrated the growth trajectory of the placenta in females is generally slower compared to males, and also shows altered adaptive responses to stressful environments. These placental adaptations are likely to depend on the type of stressor, duration, severity and the window of exposure during development. Here we describe the divergent developmental pathways between the male and female placenta contributing to altered differentiation of the TE derived trophoblast subtypes, placental growth, and formation of the placental architecture. Our focus is primarily genetic or environmental perturbations in rodent models which show altered placental responsiveness between sexes. We suggest that perturbations during early placental development may have greater impact on viability and growth of the female fetus whilst those occurring later in gestation may preferentially affect the male fetus. This may be of great relevance to human pregnancies which result from assisted reproductive technologies or complications such as pre-eclampsia and diabetes.

Programming of maternal and offspring disease: impact of growth restriction, fetal sex and transmission across generations

Babies born small are at an increased risk of developing myriad adult diseases. While growth restriction increases disease risk in all individuals, often a second hit is required to unmask 'programmed' impairments in physiology. Programmed disease outcomes are demonstrated more commonly in male offspring compared with females, with these sex-specific outcomes partly attributed to different placenta-regulated growth strategies of the male and female fetus. Pregnancy is known to be a major risk factor for unmasking a number of conditions and can be considered a 'second hit' for women who were born small. As such, female offspring often develop impairments of physiology for the first time during pregnancy that present as pregnancy complications. Numerous maternal stressors can further increase the risk of developing a maternal complication during pregnancy. Importantly, these maternal complications can have long-term consequences for both the mother after pregnancy and the developing fetus. Conditions such as preeclampsia, gestational diabetes and hypertension as well as thyroid, liver and kidney diseases are all conditions that can complicate pregnancy and have long-term consequences for maternal and offspring health. Babies born to mothers who develop these conditions are often at a greater risk of developing disease in adulthood. This has implications as a mechanism for transmission of disease across generations. In this review, we discuss the evidence surrounding long-term intergenerational implications of being born small and/or experiencing stress during pregnancy on programming outcomes.

Maternal hypomagnesemia alters renal function but does not program changes in the cardiovascular physiology of adult offspring

Maternal undernutrition is known to adversely impact fetal health and development. Insults experienced in utero alter development of the fetus as it adapts to microenvironment stressors, leading to growth restriction and subsequent low birth weight. Infants born small for gestational age have significantly increased risk of developing cardiovascular and renal disease in later life, an effect that is often characterized by hypertension and reduced glomerular number. Maternal magnesium (Mg2+) deficiency during pregnancy impairs fetal growth, however, the long-term health consequences for the offspring remain unknown. Here, we used a mouse model of dietary Mg2+ deficiency before and during pregnancy to investigate cardiovascular and renal outcomes in male and female adult offspring at 6 months of age. There were no differences between groups in 24-h mean arterial pressure or heart rate as measured by radiotelemetry. Cardiovascular responses to aversive (restraint, dirty cage switch) and non-aversive (feeding response) stressors were also similar in all groups. There were no differences in nephron number, however, Mg2+-deficient offspring had increased urine flow (in both males and females) and reduced Mg2+ excretion (in males only). Despite evidence suggesting that maternal nutrient restriction programs for hypertension in adult offspring, we found that a moderate level of maternal dietary Mg2+ deficiency did not program for a nephron deficit, or alter cardiovascular function at 6 months of age. These data suggest there are no long-term adverse outcomes for the cardiovascular health of offspring of Mg2+ deficient mothers.