Investigating maternal and neonatal health outcomes associated with continuing or ceasing dexamphetamine treatment for women with attention-deficit hyperactivity disorder during pregnancy: a retrospective cohort study.

PURPOSE: Attention-deficit hyperactivity disorder (ADHD) is becoming more commonly diagnosed in women, consequently, more women of reproductive age are taking ADHD medication, such as dexamphetamine. However, the safety associated with continuing or ceasing dexamphetamine during pregnancy is unclear. This study investigates outcomes associated with the continuation of dexamphetamine during pregnancy compared to those who ceased or were unexposed. METHODS: A population-based retrospective cohort of women from Western Australia who had been dispensed dexamphetamine during pregnancy and gave birth between 2003 and 2018. Women had either continued to take dexamphetamine throughout pregnancy (continuers, n = 547) or ceased dexamphetamine before the end of the second trimester (ceasers, n = 297). Additionally, a matched (1:1) comparison group of women who were dispensed an ADHD medication prior to pregnancy but not during pregnancy (unexposed) was included in the study (n = 844). Multivariable generalised linear models were used to compare maternal and neonatal health outcomes. RESULTS: Compared to continuers, ceasers had greater odds of threatened abortion (OR: 2.28; 95%CI: 1.00, 5.15; p = 0.049). The unexposed had some benefits compared to the continuers, which included lower risk of preeclampsia (OR: 0.58; 95%CI: 0.35, 0.97; p = 0.037), hypertension (OR: 0.32; 95%CI: 0.11, 0.93; p = 0.036), postpartum haemorrhage (OR: 0.57; 95%CI: 0.41, 0.80; p = 0.001), neonatal special care unit admittance (OR: 0.16; 95%CI: 0.12, 0.20; p < 0.001) and fetal distress (OR: 0.73; 95%CI: 0.54, 0.99; p = 0.042). CONCLUSION: Continuing dexamphetamine throughout pregnancy was not associated with an increase in adverse neonatal and maternal health outcomes compared to ceasing. Ceasing dexamphetamine during pregnancy was associated with increased odds of threatened abortion compared with continuing dexamphetamine. However, this is something that requires further investigation due to the small sample size, difficulties examining timing, and the inability to examine spontaneous abortions. The unexposed showed some benefits compared to the continuers, suggesting that where possible the cessation of dexamphetamine prior to pregnancy may be advisable.

Prenatal Opioid Exposure and Immune-Related Conditions in Children.

Importance: Prenatal opioid exposure (POE) may alter with fetal development of the immune system, which may influence long-term health and susceptibility to immune-related conditions. Objective: To compare the risk of hospitalization and emergency department presentation for immune-related conditions in children with and without POE. Design, Setting, and Participants: This retrospective, population-based cohort study used linked administrative health records of all children born in Western Australia between January 1, 2003, and December 31, 2018 (N = 401 462). Exposure: Prenatal exposure to prescription opioids (overall and by trimester), neonatal abstinence syndrome diagnosis, and opioid indication (pain or opioid use disorder [OUD]). Main Outcomes and Measures: The main outcome was hospital admissions and emergency department presentations during which a child was diagnosed with an immune-related condition, including infections, conditions associated with an overactive immune system (eg, asthma, eczema, and allergy and anaphylaxis), and autoimmune diseases diagnosed before age 5 years or June 30, 2020. Data were analyzed between August 30, 2022, and February 27, 2023. Results: Neonates with POE (1656 [0.4%]; mean [SD] gestational age, 37.7 [2.1] weeks; 836 females [50.5%]; 820 males [49.5%]) were more likely to be born preterm, have low birth weight for gestational age, and be coexposed to cigarette smoke compared with nonexposed neonates. Perinatal opioid exposure was associated with an increased risk of perinatal infection (adjusted odds ratio [AOR], 1.62; 95% CI, 1.38-1.90) and eczema and dermatitis (AOR, 11.91; 95% CI, 9.84-14.41) compared with nonexposure. Neonatal abstinence syndrome was also associated with both conditions (AOR, 2.91 [95% CI, 2.36-3.57] and 31.11 [95% CI, 24.64-39.28], respectively). Prenatal opioid exposure was also associated with an increased risk of childhood asthma (adjusted hazard ratio [AHR], 1.44; 95% CI, 1.16-1.79), but not allergies and anaphylaxis. It was also associated with an increased risk of childhood eczema and dermatitis, but only in children with POE from opioids used to treat OUD (AHR, 1.47; 95% CI, 1.08-1.99) rather than pain. In contrast, POE from opioids used for pain was associated with an increased risk of infection (AHR, 1.44; 95% CI, 1.32-1.58), but POE to opioids used to treat OUD was not. Autoimmune conditions were rare and were not observed to be associated with POE. Conclusions and Relevance: In this cohort study, POE was associated with an increased risk of infection, eczema and dermatitis, and asthma, but not allergies and anaphylaxis or autoimmune conditions. These findings highlight the importance of further study of opioid-induced immune changes during pregnancy, the potential impact on long-term health in exposed children, and the mechanisms of opioid-induced immune dysregulation.

RISING STARS: The heat is on: how does heat exposure cause pregnancy complications?

The incidence and severity of heatwaves are increasing globally with concomitant health complications. Pregnancy is a critical time in the life course at risk of adverse health outcomes due to heat exposure. Dynamic physiological adaptations, which include altered thermoregulatory pathways, occur in pregnancy. If heat dissipation is ineffective, maternal and neonate health outcomes can be compromised. Indeed, epidemiological studies and animal models reveal that exposure to heat in pregnancy likely elicits an array of health complications including miscarriage, congenital anomalies, low birth weight, stillbirth, and preterm birth. Despite these associations, the reasons for why these complications occur are unclear. An array of physiological and endocrine changes in response to heat exposure in pregnancy likely underpin the adverse health outcomes, but currently, conclusive evidence is sparse. Accompanying these fundamental gaps in knowledge is a poor understanding of what exact climatic conditions challenge pregnant physiology. Moreover, the overlay of thermoregulatory-associated behaviours such as physical activity needs to be taken into consideration when assessing the risks to human health and identifying critical populations at risk. While the health impacts from heat are largely preventable through strategic interventions, for the related clinical practice, public health, and policy approaches to be effective, the gaps in basic science understanding urgently need to be addressed.

"Well, what can I do?": An examination of the role supervisors, peers and scientific societies can play in the multicultural student experience.

International graduate students are a multi-cultural and diverse demographic of researchers that are integral to higher education globally. Although their contributions to research and innovation are acknowledged, the experiences of international students overseas are influenced by structural inequalities and challenges, some similar, and some unique to their domestic colleagues, that are often compounded by a "deficit narrative". This paper was defined by the inaugural 'Pressure Cooker' workshop held at the Australian and New Zealand Placental Association (ANZPRA) conference in 2022, and discusses some of the major institutional and social structures that can define an international student's graduate degree trajectory. Further, we provide examples of collaborative programs and methods for academics, scientific societies and domestic graduate peer groups to promote an equitable and accessible environment for all researchers.

Exploring sex differences in fetal programming for childhood emotional disorders.

In examining maternal depression, placental 11ß-HSD2 mRNA expression and offspring cortisol regulation as a potential fetal programming pathway in relation to later child emotional disorders, it has become clear that sex differences may be important to consider. This study reports on data obtained from 209 participants in the Mercy Pregnancy and Emotional Wellbeing Study (MPEWS) recruited before 20 weeks of pregnancy. Maternal depressive disorders were diagnosed using the SCID-IV and maternal childhood trauma using the Childhood Trauma Questionnaire. Placental 11ß-HSD2 mRNA was measured using qRT-PCR. For assessment of stress-induced cortisol reactivity, salivary cortisol samples were taken at 12 months of age. At 4 years of age, measurement of Childhood Emotional Disorders (depression and anxiety) was based on maternal report using the Preschool Age Psychiatric Assessment (PAPA) and internalizing symptoms using the Child Behavior Checklist (CBCL). Maternal depression in pregnancy and postpartum, and infant cortisol reactivity, was associated with internalizing symptoms for females only. For female offspring only, increased 12-month cortisol reactivity was also associated with increased emotional disorders at 4 years of age; however, there was no association with placental 11ß-HSD2 mRNA expression. In females only, the combination of lower placental 11ß-HSD2 mRNA expression and higher cortisol reactivity at 12 months of age predicted increased internalising problems. These findings suggest there may be sex differences in prenatal predictors and pathways for early childhood depression and anxiety symptoms and disorder.

Long-term exposure of mice to 890 ppm atmospheric CO2 alters growth trajectories and elicits hyperactive behaviours in young adulthood.

Atmospheric carbon dioxide (CO2 ) levels are currently at 418 parts per million (ppm), and by 2100 may exceed 900 ppm. The biological effects of lifetime exposure to CO2 at these levels is unknown. Previously we have shown that mouse lung function is altered by long-term exposure to 890 ppm CO2 . Here, we assess the broader systemic physiological responses to this exposure. Mice were exposed to either 460 or 890 ppm from preconception to 3 months of age, and assessed for effects on developmental, renal and osteological parameters. Locomotor, memory, learning and anxiety-like behaviours of the mice were also assessed. Exposure to 890 ppm CO2 increased birthweight, decreased female body weight after weaning, and, as young adults, resulted in reduced engagement in memory/learning tasks, and hyperactivity in both sexes in comparison to controls. There were no clear anxiety, learning or memory changes. Renal and osteological parameters were minimally affected. Overall, this study shows that exposure of mice to 890 ppm CO2 from preconception to young adulthood alters growth and some behaviours, with limited evidence of compensatory changes in acid-base balance. These findings highlight the potential for a direct effect of increased atmospheric CO2 on mammalian health outcomes. KEY POINTS: Long-term exposure to elevated levels of atmospheric CO2 is an uncontrolled experiment already underway. This is the first known study to assess non-respiratory physiological impacts of long-term (conception to young adulthood) exposure of mice to CO2 at levels that may arise in the atmosphere due to global emissions. Exposure to elevated CO2 , in comparison to control mice, altered growth patterns in early life and resulted in hyperactive behaviours in young adulthood. Renal and bone parameters, which are important to balance acid-base levels to compensate for increased CO2 exposure, remained relatively unaffected. This work adds to the body of evidence regarding the effects of carbon emissions on mammalian health and highlights a potential future burden of disease.

Mouse Lung Structure and Function after Long-Term Exposure to an Atmospheric Carbon Dioxide Level Predicted by Climate Change Modeling.

BACKGROUND: Climate change models predict that atmospheric carbon dioxide [CO2] levels will be between 700 and 900 ppm within the next 80 y. Despite this, the direct physiological effects of exposure to slightly elevated atmospheric CO2 (as compared with ∼410 ppm experienced today), especially when exposures extend from preconception to adulthood, have not been thoroughly studied. OBJECTIVES: In this study we aimed to assess the respiratory structure and function effects of long-term exposure to 890 ppm CO2 from preconception to adulthood using a mouse model. METHODS: We exposed mice to CO2 (∼890 ppm) from prepregnancy, through the in utero and early life periods, until 3 months of age, at which point we assessed respiratory function using the forced oscillation technique, and lung structure. RESULTS: CO2 exposure resulted in a range of respiratory impairments, particularly in female mice, including higher tissue elastance, longer chord length, and lower lung compliance. Importantly, we also assessed the lung function of the dams that gave birth to our experimental subjects. Even though these mice had been exposed to the same level of increased CO2 for a similar amount of time (∼8wk), we measured no impairments in lung function. This suggests that the early life period, when lungs are undergoing rapid growth and development, is particularly sensitive to CO2. DISCUSSION: To the best of our knowledge, this study, for the first time, shows that long-term exposure to environmentally relevant levels of CO2 can impact respiratory function in the mouse. https://doi.org/10.1289/EHP7305.

Maternal, Placental, and Fetal Responses to Intermittent Heat Exposure During Late Gestation in Mice.

Physiological adaptations during heat exposure are critical in pregnancy. Maternal thermoregulation has to accommodate the increased metabolic load of the developing fetus. Here, we assess the consequences of intermittent heat exposure, as occurs in heat waves, for maternal adaptations during pregnancy, and chronic feto-placental outcomes. Following timed mating, C57BL/6J mice were allocated to either standard animal housing temperature conditions (SH) or housing at a temperature within the thermoneutral zone (TNZ). A subset of the TNZ group was exposed to 37 °C for 8 h a day from E15.5 to E17.5 to simulate a heat wave (HW). Maternal weight gain, food intake, rectal temperature, and nesting behaviors were measured across gestation. Fetal and placental tissues were collected at E18.5. With heat exposure, maternal rectal temperature increased while food intake and nest complexity decreased. Maternal daily weight gain initially decreased due to heat exposure, but on the last day of exposure, it was comparable to the other experimental groups. These maternal responses during heat exposure impacted on the fetus, with restrictions in placental and fetal development evident just before birth. Thus, the vascular portion of the placenta, and the relative fetal head size, was smaller. Furthermore, SH and TNZ animals demonstrated distinct differences in food intake and nesting behavior during pregnancy, reinforcing the need for caution in extrapolating from animal models to humans when housing occurs outside of thermoneutral zone conditions. This study highlights the direct effects of temperature conditions on health in pregnancy and provides a foundation for future studies to investigate fetal health consequences that are associated with intermittent heat exposure.

Maternal vitamin D deficiency during rat gestation elicits a milder phenotype compared to the mouse model: Implications for the placental glucocorticoid barrier.

Maternal vitamin D deficiency disturbs fetal development and programmes neurodevelopmental complications in offspring, possibly through increased fetal glucocorticoid exposure. We aimed to determine whether prenatal exposure to excess glucocorticoids underlies our rat model of early-life vitamin D deficiency, leading to altered adult behaviours. Vitamin D deficiency reduced the expression of the glucocorticoid-inactivating enzyme Hsd11b2 in the female placenta, but did not alter maternal glucocorticoid levels, feto-placental weights, or placental expression of other glucocorticoid-related genes at mid-gestation. This differs to the phenotype previously observed in vitamin D deficient mice, and highlights important modelling considerations.

The Role of 11ß-Hydroxy Steroid Dehydrogenase Type 2 in Glucocorticoid Programming of Affective and Cognitive Behaviours.

Developmental exposure to stress hormones, i.e. glucocorticoids, is central to the process of prenatal programming of later-life health. Glucocorticoid overexposure, through stress or exogenous glucocorticoids, results in a reduced birthweight, as well as affective and neuropsychiatric outcomes in adults, combined with altered hypothalamus-pituitary-adrenal (HPA) axis activity. As such, glucocorticoids are tightly regulated during development through the presence of the metabolizing enzyme 11ß-hydroxysteroid dehydrogenase type 2 (HSD2). HSD2 is highly expressed in 2 hubs during development, i.e. the placenta and the fetus itself, protecting the fetus from inappropriate glucocorticoid exposure early in gestation. Through manipulation of HSD2 expression in the mouse placenta and fetal tissues, we are able to determine the relative contribution of glucocorticoid exposure in each compartment. Feto-placental HSD2 deletion resulted in a reduced birthweight and the development of anxiety- and depression-like behaviours in adult mice. The placenta itself is altered by glucocorticoid overexposure, which causes reduced placental weight and vascular arborisation. Furthermore, altered flow and resistance in the umbilical vessels and modification of fetal heart function and development are observed. However, brain-specific HSD2 removal (HSD2BKO) also generated adult phenotypes of depressive-like behaviour and memory deficits, demonstrating the importance of fetal brain HSD2 expression in development. In this review we will discuss potential mechanisms underpinning early-life programming of adult neuropsychiatric disorders and the novel therapeutic potential of statins.

Vitamin D is crucial for maternal care and offspring social behaviour in rats.

Early life vitamin D plays a prominent role in neurodevelopment and subsequent brain function, including schizophrenic-like outcomes and increasing evidence for an association with autism spectrum disorder (ASD). Here, we investigate how early life vitamin D deficiency during rat pregnancy and lactation alters maternal care and influences neurodevelopment and affective, cognitive and social behaviours in male adult offspring. Sprague-Dawley rats were placed on either a vitamin D control (2195 IU/kg) or deficient diet (0 IU/kg) for five weeks before timed mating, and diet exposure was maintained until weaning of offspring on postnatal day (PND) 23. MRI scans were conducted to assess brain morphology, and plasma corticosterone levels and neural expression of genes associated with language, dopamine and glucocorticoid exposure were characterised at PND1, PND12 and 4 months of age. Compared to controls, vitamin D-deficient dams exhibited decreased licking and grooming of their pups but no differences in pup retrieval. Offspring neurodevelopmental markers were unaltered, but vitamin D-deficient pup ultrasonic vocalisations were atypical. As adults, males that had been exposed to vitamin D deficiency in early life exhibited decreased social behaviour, impaired learning and memory outcomes and increased grooming behaviour, but unaltered affective behaviours. Accompanying these behavioural changes was an increase in lateral ventricle volume, decreased cortical FOXP2 (a protein implicated in language and communication) and altered neural expression of genes involved in dopamine and glucocorticoid-related pathways. These data highlight that early life levels of vitamin D are an important consideration for maternal behavioural adaptations as well as offspring neuropsychiatry.

Viscosity and haemodynamics in a late gestation rat feto-placental arterial network.

The placenta is a transient organ which develops during pregnancy to provide haemotrophic support for healthy fetal growth and development. Fundamental to its function is the healthy development of vascular trees in the feto-placental arterial network. Despite the strong association of haemodynamics with vascular remodelling mechanisms, there is a lack of computational haemodynamic data that may improve our understanding of feto-placental physiology. The aim of this work was to create a comprehensive 3D computational fluid dynamics model of a substructure of the rat feto-placental arterial network and investigate the influence of viscosity on wall shear stress (WSS). Late gestation rat feto-placental arteries were perfused with radiopaque Microfil and scanned via micro-computed tomography to capture the feto-placental arterial geometry in 3D. A detailed description of rat fetal blood viscosity parameters was developed, and three different approaches to feto-placental haemodynamics were simulated in 3D using the finite volume method: Newtonian model, non-Newtonian Carreau-Yasuda model and Fåhræus-Lindqvist effect model. Significant variability in WSS was observed between different viscosity models. The physiologically-realistic simulations using the Fåhræus-Lindqvist effect and rat fetal blood estimates of viscosity revealed detailed patterns of WSS throughout the arterial network. We found WSS gradients at bifurcation regions, which may contribute to vessel enlargement, and sprouting and pruning during angiogenesis. This simulation of feto-placental haemodynamics shows the heterogeneous WSS distribution throughout the network and demonstrates the ability to determine physiologically-relevant WSS magnitudes, patterns and gradients. This model will help advance our understanding of vascular physiology and remodelling in the feto-placental network.

Vitamin D deficiency and impaired placental function: potential regulation by glucocorticoids?

Maternal vitamin D deficiency has been implicated in a range of pregnancy complications including preeclampsia, preterm birth and intrauterine growth restriction. Some of these adverse outcomes arise from alterations in placental function. Indeed, vitamin D appears critical for implantation, inflammation, immune function and angiogenesis in the placenta. Despite these associations, absence of the placental vitamin D receptor in mice provokes little effect. Thus, interactions between maternal and fetal compartments are likely crucial for instigating adverse placental changes. Indeed, maternal vitamin D deficiency elicits changes in glucocorticoid-related parameters in pregnancy, which increase placental and fetal glucocorticoid exposure. As in utero glucocorticoid excess has a well-established role in eliciting placental dysfunction and fetal growth restriction, this review proposes that glucocorticoids are an important consideration when understanding the impact of vitamin D deficiency on placental function and fetal development.

Pregnancy Suppresses the Daily Rhythmicity of Core Body Temperature and Adipose Metabolic Gene Expression in the Mouse.

Maternal adaptations in lipid metabolism are crucial for pregnancy success due to the role of white adipose tissue as an energy store and the dynamic nature of energy needs across gestation. Because lipid metabolism is regulated by the rhythmic expression of clock genes, it was hypothesized that maternal metabolic adaptations involve changes in both adipose clock gene expression and the rhythmic expression of downstream metabolic genes. Maternal core body temperature (Tc) was investigated as a possible mechanism driving pregnancy-induced changes in clock gene expression. Gonadal adipose tissue and plasma were collected from C57BL/6J mice before and on days 6, 10, 14, and 18 of pregnancy (term 19 d) at 4-hour intervals across a 24-hour period. Adipose expression of clock genes and downstream metabolic genes were determined by quantitative RT-PCR, and Tc was measured by intraperitoneal temperature loggers. Adipose clock gene expression showed robust rhythmicity throughout pregnancy, but absolute levels varied substantially across gestation. Rhythmic expression of the metabolic genes Lipe, Pnpla2, and Lpl was clearly evident before pregnancy; however, this rhythmicity was lost with the onset of pregnancy. Tc rhythm was significantly altered by pregnancy, with a 65% decrease in amplitude by term and a 0.61°C decrease in mesor between days 6 and 18. These changes in Tc, however, did not appear to be linked to adipose clock gene expression across pregnancy. Overall, our data show marked adaptations in the adipose clock in pregnancy, with an apparent decoupling of adipose clock and lipolytic/lipogenic gene rhythms from early in gestation.

Pregnancy-induced changes in the circadian expression of hepatic clock genes: implications for maternal glucose homeostasis.

Adaptations in maternal carbohydrate metabolism are particularly important in pregnancy because glucose is the principal energy substrate used by the fetus. As metabolic homeostasis is intricately linked to the circadian system via the rhythmic expression of clock genes, it is likely that metabolic adaptations during pregnancy also involve shifts in maternal circadian function. We hypothesized that maternal adaptation in pregnancy involves changes in the hepatic expression of clock genes, which drive downstream shifts in circadian expression of glucoregulatory genes. Maternal liver and plasma (n = 6-8/group) were collected across 24-h periods (0800, 1200, 1600, 2000, 0000, 0400) from C57Bl/6J mice under isoflurane-nitrous oxide anesthesia prior to and on days 6, 10, 14 and 18 of pregnancy (term = day 19). Hepatic expression of clock genes and glucoregulatory genes was determined by RT-qPCR. Hepatic clock gene expression was substantially altered across pregnancy, most notably in late gestation when the circadian rhythmicity of several clock genes was attenuated (≤64% reduced amplitude on day 18). These changes were associated with a similar decline in rhythmicity of the key glucoregulatory genes Pck1, G6Pase, and Gk, and by day 18, Pck1 was no longer rhythmic. Overall, our data show marked adaptations in the liver clock during mouse pregnancy, changes that may contribute to the altered circadian variation in glucoregulatory genes near term. We propose that the observed reduction of daily oscillations in glucose metabolism ensure a sustained supply of glucose to meet the high demands of fetal growth.

Pravastatin ameliorates placental vascular defects, fetal growth, and cardiac function in a model of glucocorticoid excess.

Fetoplacental glucocorticoid overexposure is a significant mechanism underlying fetal growth restriction and the programming of adverse health outcomes in the adult. Placental glucocorticoid inactivation by 11ß-hydroxysteroid dehydrogenase type 2 (11ß-HSD2) plays a key role. We previously discovered that Hsd11b2(-/-) mice, lacking 11ß-HSD2, show marked underdevelopment of the placental vasculature. We now explore the consequences for fetal cardiovascular development and whether this is reversible. We studied Hsd11b2(+/+), Hsd11b2(+/-), and Hsd11b2(-/-) littermates from heterozygous (Hsd11b(+/-)) matings at embryonic day (E)14.5 and E17.5, where all three genotypes were present to control for maternal effects. Using high-resolution ultrasound, we found that umbilical vein blood velocity in Hsd11b2(-/-) fetuses did not undergo the normal gestational increase seen in Hsd11b2(+/+) littermates. Similarly, the resistance index in the umbilical artery did not show the normal gestational decline. Surprisingly, given that 11ß-HSD2 absence is predicted to initiate early maturation, the E/A wave ratio was reduced at E17.5 in Hsd11b2(-/-) fetuses, suggesting impaired cardiac function. Pravastatin administration from E6.5, which increases placental vascular endothelial growth factor A and, thus, vascularization, increased placental fetal capillary volume, ameliorated the aberrant umbilical cord velocity, normalized fetal weight, and improved the cardiac function of Hsd11b2(-/-) fetuses. This improved cardiac function occurred despite persisting indications of increased glucocorticoid exposure in the Hsd11b2(-/-) fetal heart. Thus, the pravastatin-induced enhancement of fetal capillaries within the placenta and the resultant hemodynamic changes correspond with restored fetal cardiac function. Statins may represent a useful therapeutic approach to intrauterine growth retardation due to placental vascular hypofunction.

Pregnancy-induced adaptations of the central circadian clock and maternal glucocorticoids.

Maternal physiological adaptations, such as changes to the hypothalamic-pituitary-adrenal (HPA) axis, are central to pregnancy success. Circadian variation of the HPA axis is dependent on clock gene rhythms in the hypothalamus, but it is not known whether pregnancy-induced changes in maternal glucocorticoid levels are mediated via this central clock. We hypothesized that hypothalamic expression of clock genes changes across mouse pregnancy and this is linked to altered HPA activity. The anterior hypothalamus and maternal plasma were collected from C57Bl/6J mice prior to pregnancy and on days 6, 10, 14 and 18 of gestation (term=d19), across a 24-h period (0800, 1200, 1600, 2000, 0000, 0400 h). Hypothalamic expression of clock genes and Crh was determined by qPCR, plasma ACTH concentration measured by Milliplex assay and plasma corticosterone concentration by LC-MS/MS. Expression of all clock genes varied markedly across gestation, most notably at mid-gestation when levels of each gene were elevated. The pregnancy-induced increase in maternal corticosterone levels (by up to 14-fold on day 14) was not accompanied by a parallel shift in plasma ACTH (28% lower on day 14 compared with non-pregnant levels). Moreover, while circadian rhythmicity in corticosterone was maintained up to day 14 of gestation, this was effectively lost by day 18. Overall, our data show that the central circadian clock undergoes marked adaptations throughout mouse pregnancy, changes that are likely to contribute to maternal physiological adaptations. Importantly, however, neither hypothalamic clock genes nor plasma ACTH levels appear to drive the marked increase in maternal corticosterone after mid-gestation.

Vitamin D Deficiency in BALB/c Mouse Pregnancy Increases Placental Transfer of Glucocorticoids.

The prevalence of vitamin D deficiency in pregnancy is increasing and implicated in adverse consequences for the health of offspring in later life. The aim of this study was to determine whether vitamin D deficiency increases fetal exposure to glucocorticoids, which are known to alter fetal development and result in adverse adult health outcomes. Female BALB/c mice were placed on either a vitamin D control (2195 IU/kg) or deficient (0 IU/kg) diet for 5 weeks before and during pregnancy. Maternal serum, placentas and fetal brains were collected at embryonic day 14.5 or 17.5 for morphological and gene expression analysis. Vitamin D deficiency during pregnancy increased maternal corticosterone concentrations and reduced placental weight. Maternal vitamin D deficiency decreased placental expression of 11ß-hydroxysteroid dehydrogenase type II, which inactivates glucocorticoids thereby protecting the fetus from inappropriate glucocorticoid exposure. There was a corresponding increase in placental and fetal expression of the highly glucocorticoid-sensitive factor glucocorticoid-induced leucine zipper. Furthermore, placental expression of the angiogenic factor vascular endothelial growth factor-A was reduced in vitamin D-deficient pregnancies, with a corresponding decline in fetal capillary volume within the placenta. Overall, we show that prenatal vitamin D deficiency leads to an increase in maternal corticosterone, alterations in genes indicative of increased fetal glucocorticoid exposure and impairment in placental vascular development. Thus, the long-term adverse health consequences of vitamin D deficiency during early development may not just be due to alteration in direct vitamin D-related pathways but also altered fetal glucocorticoid exposure.

Maternal vitamin D deficiency alters fetal brain development in the BALB/c mouse.

Prenatal exposure to vitamin D is thought to be critical for optimal fetal neurodevelopment, yet vitamin D deficiency is apparent in a growing proportion of pregnant women. The aim of this study was to determine whether a mouse model of vitamin D-deficiency alters fetal neurodevelopment. Female BALB/c mice were placed on either a vitamin D control (2,195 IU/kg) or deficient (0 IU/kg) diet for 5 weeks prior to and during pregnancy. Fetal brains were collected at embryonic day (E) 14.5 or E17.5 for morphological and gene expression analysis. Vitamin D deficiency during pregnancy reduced fetal crown-rump length and head size. Moreover, lateral ventricle volume was reduced in vitamin D-deficient foetuses. Expression of neurotrophin genes brain-derived neurotrophic factor (Bdnf) and transforming growth factor-ß1 (Tgf-ß1) was altered, with Bdnf reduced at E14.5 and increased at E17.5 following vitamin D deficiency. Brain expression of forkhead box protein P2 (Foxp2), a gene known to be important in human speech and language, was also altered. Importantly, Foxp2 immunoreactive cells in the developing cortex were reduced in vitamin D-deficient female foetuses. At E17.5, brain tyrosine hydroxylase (TH) gene expression was reduced in females, as was TH protein localization (to identify dopamine neurons) in the substantia nigra of vitamin D-deficient female foetuses. Overall, we show that prenatal vitamin D-deficiency leads to alterations in fetal mouse brain morphology and genes related to neuronal survival, speech and language development, and dopamine synthesis. Vitamin D appears to play an important role in mouse neurodevelopment.