Impact of parental over- and underweight on the health of offspring

The relevance of female overweight in infertility treatment: a position statement of the Italian Society of Fertility and Sterility and Reproductive Medicine (SIFES-MR)

PURPOSE

Obesity is increasingly at the center of modern international healthcare systems. This is a position statement of the Italian Society of Fertility and Sterility and Reproductive Medicine (SIFES-MR) aimed at evaluating the impact of female overweight on infertility in order to improve fertility outcomes, including Assisted Reproductive technology (ART) treatments.

METHODS

The SIFES-MR writing group for this position statement was composed by Italian reproductive physicians, embryologists, and scientists with expertise in fertility evaluation, assisted reproduction technologies, and laboratory quality management. The positions stated are based on consensus by the authors, who met over a six-month period. The consensus emerged after thorough review of pertinent literature and standards concerning the impact of female overweight, complemented by extensive dialogue and discussion among the authors. Additionally, input from society members was considered, leading to revisions and eventual approval by the SIFES-MR governing council.

RESULTS

An increasing number of women affected by overweight and infertility accessing to ART treatments are expected in the future. A comprehensive counseling since the first access to infertility care is mandatory and should promote weight restoration, with the aim to improve the likelihood of spontaneous unassisted conception. Careful preconceptional evaluation of obese women is strongly encouraged for counseling purpose and comorbidities should be corrected by a multidisciplinary approach before spontaneous or medically assisted conception. Indeed, female obesity is responsible for high-risk pregnancies, with potential consequences in infants and during childhood. When in vitro fertilization is indicated, the risk of venous thromboembolism exacerbated by controlled ovarian stimulation should be assessed.

CONCLUSIONS

Before IVF, different therapeutic approaches and expectant management to reduce overweight could be offered, and the age-related algorithm herein proposed by SIFES may represent an interesting tool for a better personalization of infertility care in these women. The treatment of infertility cannot ignore the correct management of female overweight, given the serious consequences that this condition can have on the outcomes of pregnancies and future generations. IVF specialists should tailor access and modalities of IVF treatment to this class of high-risk women.

Association Between Maternal Prepregnancy and Pregnancy Body Mass Index and Children's Telomere Length: A Systematic Review and Meta-analysis

CONTEXT

Telomeres maintain chromosome stability and mark cellular aging, and their shortening with age compromises genomic stability.

OBJECTIVE

The purpose of this study was to conduct a meta-analysis of existing evidence to evaluate the relationship between the maternal pregnancy body mass index (BMI) and children's telomere length (TL).

DATA SOURCE

Web of Science, Scopus, and PubMed databases were systematically searched from their inception to August 27, 2023, for pertinent observational studies.

DATA EXTRACTION

The random-effects meta-analysis was conducted on eligible studies that investigated the linear relationship between exposure and the outcomes of interest, utilizing the reported β-coefficient. Cochran's Q test and I2 statistics were used to assess heterogeneity.

DATA ANALYSIS

A significant association was observed between maternal pregnancy BMI and children's TL (32 studies, pooled effect size [ES]: -0.04; 95% CI: -0.06 to -0.01; I2 = 47.51%, P < .001) and maternal prepregnancy BMI and children's TL at birth (16 studies; pooled ES: -0.05; 95% CI: -0.08 to -0.02; I2 = 53.49%, P < .001).

CONCLUSION

The findings indicate an inverse association between maternal prepregnancy BMI and TL in infants, which is evident within the normal to obese BMI range. This underscores the significance of maternal weight status before pregnancy as a determinant of offspring TL.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023466425.

Grandmaternal prepregnancy body mass index and infant birthweight: a mediation analysis of maternal prepregnancy body mass index

The objectives of this study were to examine the total effect of grandmaternal (G0) prepregnancy body mass index (BMI) on infant (G2) birthweight z score and to quantify the mediation role of maternal (G1) prepregnancy BMI. Data were extracted from the Nova Scotia 3G Multigenerational Cohort. The association between G0 prepregnancy BMI and G2 birthweight z score and the mediated effect by G1 prepregnancy BMI were estimated using g-computation with adjustment for confounders identified using a directed acyclic graph and accounting for intermediate confounding. A total of 20 822 G1-G2 dyads from 18 450 G0 participants were included. Relative to G0 normal weight, G0 underweight decreased mean G2 birthweight z score (-0.11; 95% CI, -0.20 to -0.030), whereas G0 overweight and obesity increased mean G2 birthweight z score (0.091 [95% CI, 0.034-0.15] and 0.22 [95% CI, 0.11-0.33], respectively). G1 prepregnancy BMI partly mediated the association, with the largest effect size observed for G0 obesity (0.11; 95% CI, 0.080-0.14). Estimates of the direct effect were close to the null. In conclusion, grandmaternal prepregnancy BMI was associated with infant birthweight z score. Maternal prepregnancy BMI partly mediated the association, suggesting that factors related to BMI may play an important role in the transmission of weight across the maternal line.

Targeting the Epigenetic Marks in Type 2 Diabetes Mellitus: Will Epigenetic Therapy Be a Valuable Adjunct to Pharmacotherapy?

Although genetic, environmental, and lifestyle factors largely contribute to type 2 diabetes mellitus (T2DM) risk, the role of epigenetics in its pathogenesis is now well established. The epigenetic mechanisms in T2DM mainly consist of DNA methylation, histone modifications and regulation by noncoding RNAs (ncRNAs). For instance, DNA methylation at CpG islands in the promoter regions of specific genes encoding insulin signaling and glucose metabolism suppresses these genes. Modulating the enzyme mediators of these epigenetic marks aims to restore standard gene expression patterns and improve glycemic control. In targeting these epigenetic marks, using epigenetic drugs such as DNA methyltransferase (DNAMT), histone deacetylase (HDAC) and histone acetyltransferase (HAT) inhibitors has led to variable success in humans and experimental murine models. Specifically, the United States' Food and Drug Administration (US FDA) has approved DNAMT inhibitors like 5-azacytidine and 5-aza-2'-deoxycytidine for use in diabetic retinopathy: a T2DM microvascular complication. These DNAMT inhibitors block the genes for methylation of mitochondrial superoxide dismutase 2 (SOD2) and matrix metallopeptidase 9 (MMP-9): the epigenetic marks in diabetic retinopathy. Traditional pharmacotherapy with metformin also have epigenetic effects in T2DM and positively alter disease outcomes when combined with epigenetic drugs like DNAMT and HDAC inhibitors, raising the prospect of using epigenetic therapy as a valuable adjunct to pharmacotherapy. However, introducing small interfering RNAs (siRNAs) in cells to silence specific target genes remains in the exploratory phase. Future research should focus on regulating gene expression in T2DM using long noncoding RNA (lncRNA) molecules, another type of ncRNA. This review discusses the epigenetics of T2DM and that of its macro- and microvascular complications, and the potential benefits of combining epigenetic therapy with pharmacotherapy for optimal results.

Pre-pregnancy obesity is associated with greater systemic inflammation and increased risk of antenatal depression

BACKGROUND

Pre-pregnancy obesity is an emerging risk factor for perinatal depression. However, the underlying mechanisms remain unclear. We investigated the association between pre-pregnancy body mass index (BMI) and perinatal depressive symptoms in a large population-based pre-birth cohort, the Barwon Infant Study. We also assessed whether the levels of circulating inflammatory markers during pregnancy mediated this relationship.

METHODS

Depressive symptoms were assessed in 883 women using the Edinburgh Postnatal Depression Scale (EPDS) and psychological stress using the Perceived Stress Scale (PSS) at 28 weeks gestation and 4 weeks postpartum. Glycoprotein acetyls (GlycA), high-sensitivity C-reactive protein (hsCRP) and cytokines were assessed at 28 weeks gestation. We performed regression analyses, adjusted for potential confounders, and investigated mediation using nested counterfactual models.

RESULTS

The estimated effect of pre-pregnancy obesity (BMI ≥ 30 kg/m2) on antenatal EPDS scores was 1.05 points per kg/m2 increase in BMI (95% CI: 0.20, 1.90; p = 0.02). GlycA, hsCRP, interleukin (IL) -1ra and IL-6 were higher in women with obesity, compared to healthy weight women, while eotaxin and IL-4 were lower. Higher GlycA was associated with higher EPDS and PSS scores and partially mediated the association between pre-pregnancy obesity and EPDS/PSS scores in unadjusted models, but this association attenuated upon adjustment for socioeconomic adversity. IL-6 and eotaxin were negatively associated with EPDS/PSS scores, however there was no evidence for mediation.

CONCLUSIONS

Pre-pregnancy obesity increases the risk of antenatal depressive symptoms and is also associated with systemic inflammation during pregnancy. While discrete inflammatory markers are associated with antenatal depressive symptoms and perceived stress, their role in mediating the effects of pre-pregnancy obesity on antenatal depression requires further investigation.

Pregorexia: a systematic review and meta-analysis on the constructs of body image dissatisfaction and eating disturbances by gestational age in the peripartum

PURPOSE

Pregorexia is a phenomenon posited to occur in the peripartum, characterized by an attempt to counter pregnancy's physiological changes in body shape through reduced calorie intake or increased physical activity.

METHODS

In this pre-registered systematic review and meta-analysis, body image dissatisfaction and eating psychopathology in the peripartum according to gestational age were formally assessed. PubMed was searched up to May 2023. Selection criteria were represented by studies on body image concerns or eating psychopathology in the peripartum (up to 1 year after delivery). The population needed to include women from the general population or among patients with a history of (or current) eating disorder. For the meta-analysis, 17 studies were included: 10 for body image dissatisfaction (2625 individuals overall), 7 for eating behaviors (2551 individuals overall). The interplay between body image and the following themes was examined in depth: the adoption of breastfeeding, peripartum depression, sociocultural influences on body image, sexual disturbances, experiencing or reporting an altered food intake.

RESULTS

Progressive dissatisfaction with body image during pregnancy by gestational age was observed, stably elevated for at least 12 months postpartum. Eating psychopathology was observed as elevated only at 12 months in the postpartum, but not during pregnancy.

DISCUSSION

The current work offers normative values of body image satisfaction and eating psychopathology in the peripartum by gestational age. The relevance of current results was discussed, in order to inform both current clinical practice and future public policies.

LEVEL OF EVIDENCE

Level I-Evidence obtained from: systematic reviews and meta-analyses.

Does the risk of embryo abnormality increase in PCOS women? A secondary analysis of a multi-center randomized controlled trial

CONTEXT

Some studies reported the early miscarriage rate was higher in PCOS women. However, whether the risk of embryo abnormalities increases in PCOS women is lack of evidence.

OBJECTIVE

To evaluate the association between polycystic ovarian syndrome (PCOS) and embryo ploidy.

DESIGN

A secondary analysis of multi-center randomized controlled trial which was conducted from July 2017 to June 2018. The original intent was to identify whether preimplantation genetic test for aneuploidy (PGT-A) improves the live birth rate as compared with in-vitro fertilization (IVF).

SETTING

14 reproductive centers.

PATIENTS

190 patients diagnosed with PCOS and 1:1 age-matched non-PCOS patients were chosen from PGT-A group. A total of 380 patients with 1118 embryos were included in our study.

INTERVENTIONS

Women diagnosed with PCOS.

MAIN OUTCOME MEASURES

Embryonic aneuploidy and embryonic mosaic.

RESULTS

After adjusted for potential confounders, the rate of embryonic aneuploidy and embryonic mosaic in PCOS group were comparable with control group [embryonic aneuploid rate PCOS group: 14.0% vs control group: 18.3%, adjusted OR (95%CI): 0.78(0.54,1.12), P = 0.19; embryonic mosaic rate 10.9% vs 10.1%, adjusted OR (95%CI): 0.91(0.59,1.40), P = 0.66]. We further stratified PCOS women into four groups according to phenotype. The rate of aneuploid and mosaic embryos was comparable between each of PCOS phenotype and control group. There was still no significant difference of embryonic aneuploid and embryo mosaic rates within four phenotypes.

CONCLUSIONS

The risk of aneuploid and mosaic embryos was not increased in PCOS women. Thus, we suggests that the miscarriage rate arising from abnormal embryonic chromosomes could be similar between PCOS and non-PCOS women.

Sodium-to-Potassium Ratio as an Indicator of Diet Quality in Healthy Pregnant Women

This study aimed to investigate diet quality in healthy pregnant women based on the Na-to-K ratio from 24 h urine sample and food frequency questionnaire (FFQ), to compare dietary micro- and macronutrient intake with current nutritional recommendations (RDA), and to investigate whether gestational weight gain (GWG) is associated with Na-to-K ratio and diet quality during pregnancy in general. Sixty-four healthy pregnant women between 37 and 40 weeks of gestation participated in the study. Participants' GWG, body composition, molar 24 h urine Na-to-K ratio, and FFQ data on average daily total energy, food groups, and micro-/macronutrient intake were obtained. A Na-to-K ratio of 2.68 (1.11-5.24) does not meet nutrition quality and is higher than the WHO recommendations due to excessive sodium and insufficient potassium intake. FFQ Na-to-K ratio was associated with a higher daily intake of soups, sauces, cereals, fats, and oils and a low intake of fruit and non-alcoholic beverages. A total of 49% of pregnant women exhibited excessive GWG, which was attributed to the increase in adipose tissue mass. GWG was not associated with total energy but may be the result of insufficient physical activity during pregnancy. Daily intake of vitamin D, vitamin E, folate, niacin, riboflavin, calcium, iron, and zinc was suboptimal compared to RDA.

BMI and miscarriage after IVF

PURPOSE OF REVIEW

To summarize recent findings related to the risk of miscarriage in women with elevated BMI undergoing IVF, and the mechanisms involved in said risk.

RECENT FINDINGS

Miscarriage rates are increased in overweight and obese women in both natural and assisted reproduction. Oocyte and embryo quality assessed according to classic morphological static parameters does not seem to be affected by excessive female body weight. Despite the initial lack of consensus between studies regarding embryo morphokinetics in obese women, blastocyst formation and quality have recently been shown to be similar across BMI groups, even in the case of euploid embryos. However, some metabolomic differences have been described in oocytes and embryos from obese women, thus pointing to a functional alteration. In women with elevated BMI, the percentage of aneuploid embryos is similar to that of normal weight women, and rates of miscarriage are higher, despite the transfer of euploid embryos. Therefore, the origin of the increased pregnancy loss rate after IVF in these women may be related to metabolomic, epigenetic or mitochondrial oocyte and embryo disturbances, or to the abnormal endocrine, metabolic and inflammatory uterine environment induced by obesity, which seems to be also responsible for other numerous complications during pregnancy and the in-utero fetal programming of postnatal diseases. A displacement of the window of implantation in obese women undergoing artificial endometrial preparation has recently been described and may be related to the poorer embryo implantation rates and increased risk of miscarriage observed following fresh and frozen embryo transfers with autologous oocytes, and with donated ova in recipients with extremely high BMI.

SUMMARY

Female obesity is related to poorer outcome in natural and assisted conception, including an increased risk of miscarriage. Embryo morphology, assessed by conventional methods or by morphokinetics, does not seem to be affected by excess weight, with similar blastocyst formation and quality than normal weight women reported in IVF cycles. Embryo aneuploidy is not increased, and higher miscarriages rates are seen after euploid embryo transfer in obese women. Disturbances of the uterus or its environment induced by female obesity seem to be the most likely cause of the increased risk of miscarriage, although metabolomic, epigenetic or mitochondrial oocyte and embryo dysfunction cannot be ruled out as cannot congenital anomalies. In the context of all the above, weight reduction before pregnancy should be advised in obese women trying to become pregnant.

Early programming of reproductive health and fertility: novel neuroendocrine mechanisms and implications in reproductive medicine

BACKGROUND

According to the Developmental Origins of Health and Disease (DOHaD) hypothesis, environmental changes taking place during early maturational periods may alter normal development and predispose to the occurrence of diverse pathologies later in life. Indeed, adverse conditions during these critical developmental windows of high plasticity have been reported to alter the offspring developmental trajectory, causing permanent functional and structural perturbations that in the long term may enhance disease susceptibility. However, while solid evidence has documented that fluctuations in environmental factors, ranging from nutrient availability to chemicals, in early developmental stages (including the peri-conceptional period) have discernible programming effects that increase vulnerability to develop metabolic perturbations, the impact and eventual mechanisms involved, of such developmental alterations on the reproductive phenotype of offspring have received less attention.

OBJECTIVE AND RATIONALE

This review will summarize recent advances in basic and clinical research that support the concept of DOHaD in the context of the impact of nutritional and hormonal perturbations, occurring during the periconceptional, fetal and early postnatal stages, on different aspects of reproductive function in both sexes. Special emphasis will be given to the effects of early nutritional stress on the timing of puberty and adult gonadotropic function, and to address the underlying neuroendocrine pathways, with particular attention to involvement of the Kiss1 system in these reproductive perturbations. The implications of such phenomena in terms of reproductive medicine will also be considered.

SEARCH METHODS

A comprehensive MEDLINE search, using PubMed as main interface, of research articles and reviews, published mainly between 2006 and 2021, has been carried out. Search was implemented using multiple terms, focusing on clinical and preclinical data from DOHaD studies, addressing periconceptional, gestational and perinatal programming of reproduction. Selected studies addressing early programming of metabolic function have also been considered, when relevant.

OUTCOMES

A solid body of evidence, from clinical and preclinical studies, has documented the impact of nutritional and hormonal fluctuations during the periconceptional, prenatal and early postnatal periods on pubertal maturation, as well as adult gonadotropic function and fertility. Furthermore, exposure to environmental chemicals, such as bisphenol A, and maternal stress has been shown to negatively influence pubertal development and gonadotropic function in adulthood. The underlying neuroendocrine pathways and mechanisms involved have been also addressed, mainly by preclinical studies, which have identified an, as yet incomplete, array of molecular and neurohormonal effectors. These include, prominently, epigenetic regulatory mechanisms and the hypothalamic Kiss1 system, which likely contribute to the generation of reproductive alterations in conditions of early nutritional and/or metabolic stress. In addition to the Kiss1 system, other major hypothalamic regulators of GnRH neurosecretion, such as γ-aminobutyric acid and glutamate, may be targets of developmental programming.

WIDER IMPLICATIONS

This review addresses an underdeveloped area of reproductive biology and medicine that may help to improve our understanding of human reproductive disorders and stresses the importance, and eventual pathogenic impact, of early determinants of puberty, adult reproductive function and fertility.

Reprotoxic Impact of Environment, Diet, and Behavior

Reproductive health is progressively declining due to multiples endogenous and exogenous factors, such as environmental contaminants, diet and behavior. Accumulated evidences confirm that fertility and reproductive function have been adversely affected by exposure to chemical contaminants released in the environment. Today, the impact of diet and behavior on reproductive processes is also receiving special attention from the scientific community. Indeed, a close relationship between diet and fertility has been proven. Furthermore, a combination of unhealthy behavior, such as exposure to hazardous compounds and stress factors, poses living organisms at higher risk of reprotoxic effects. In particular, it has been described that poor life behaviors are associated with reduced male and female fertility due to decreased gamete quality and function. Most of the erroneous behaviors are, furthermore, a source of oxidative stress that, leading to epigenetic alterations, results in an impaired reproductive fitness. This review reports the detrimental impact of the most common environmental chemical stressors, diet, and behavior on reproductive functionality and success. Although clear evidences are still scarce, reassuring data are provided that a healthy diet and reverting unhealthy lifestyles may be of help to recover physiological reproductive conditions.

Association between clinical and IVF laboratory parameters and miscarriage after single euploid embryo transfers

BACKGROUND

The goal of this study was to investigate which factors, excluding embryo aneuploidies, are associated with miscarriage in patients who have undergone a single euploid blastocyst transfer.

METHODS

Retrospective, observational and multicenter study with 2832 patients undergoing preimplantational genetic testing for aneuploidies (PGT-A) due to repeated implantation failure, recurrent pregnancy loss, advanced maternal age or severe male factor were transferred one single euploid embryo.

RESULTS

One of the main findings was a significant relationship between body mass index (BMI) and miscarriage rates (13.4% in underweight women, 12.1% in normal weight, 14.5% in overweight, and 19.2% in obese women, odds ratio [OD] 1.04; 95% confidence interval [CI], 1.01-1.07 p = 0.006). Endometrial thickness (OD 0.65; 95%, 0.52-0.77 p = 0.04) and type of endometrial preparation (natural cycle or hormone replacement cycle) (OD 0.77; 95%, 0.52-0.77, p = 0.04) were also associated with miscarriage rates.

CONCLUSIONS

BMI was strongly associated to miscarriage rates. We also observed a weaker association with endometrial thickness and with the type of endometrial preparation (natural cycle or hormone replacement cycle). None of the other studied variables (biopsy day, maternal and male age, duration of infertility, cycle length, previous miscarriages, previous live births, previous In Vitro Fertilization (IVF) cycles, endometrial pattern and/or diagnosis) were associated with miscarriage rates.

Parental Adherence to Ideal Cardiovascular Health Status Was Associated With a Substantially Lower Prevalence of Overweight and Obesity in Their Offspring Aged 6-18 Years

Background: Parental health status had a potential influence on offspring health. This study aimed to investigate the separate associations between paternal and maternal cardiovascular health statuses and the prevalence of childhood overweight and obesity in the offspring. Methods: Data were from a cross-sectional study conducted in seven provinces or cities of China in 2013. A total of 29,317 children aged 6-18 years old and their parents, making up 9,585 father-offspring pairs and 19,732 mother-offspring pairs, were included in the final analysis. Information on parental cardiovascular health status factors (dietary behaviors, body mass index (BMI), smoking, physical activity, hypertension, and diabetes mellitus) was obtained from the structured self-administrated questionnaires. Based on the health status factors, we then generated an ideal cardiovascular health (iCVH) score. The overweight and obesity of children were defined using age- and sex-specific cutoffs based on the International Obesity Task Force criteria. A multilevel log-binomial regression model was used to assess the association between parental cardiovascular health status and prevalence of childhood overweight and obesity in the offspring. Results: The prevalence of pediatric overweight and obesity was 22.0% in the father-offspring subset and 23.8% in the mother-offspring subset, respectively. Fathers with ideal BMI, non-smoking, and absence of hypertension and diabetes, and mothers with ideal BMI, ideal physical activity, and absence of hypertension and diabetes were found to be associated with lower prevalence of overweight and obesity in the offspring. The prevalence of offspring overweight and obesity was significantly decreased with the parental iCVH scores increased. Each additional increase in paternal and maternal iCVH factor was associated with a 30% and 27% lower prevalence of overweight and obesity in the offspring. Compared with children whose parental iCVH scores ≤ 3, offspring whose fathers or mothers met all six iCVH factors had 67% [prevalence ratio (PR): 0.33, 95%CI: 0.25-0.42] and 58% (PR: 0.42, 95%CI: 0.29-0.62) lower prevalence of overweight and obesity, respectively. Conclusions: Parental adherence to iCVH status was associated with a lower prevalence of pediatric overweight and obesity in offspring. Our findings support the intervention strategy that parents should involve in the obesity intervention program for children.

Nutritional consequences and management of hyperemesis gravidarum: a narrative review

Hyperemesis gravidarum (HG) is a condition at the extreme end of the pregnancy sickness spectrum, estimated to affect 1-2 % of pregnant women. This narrative review provides an overview of the current literature concerning the nutritional implications and management of HG. HG can persist throughout pregnancy, causing malnutrition, dehydration, electrolyte imbalance and unintended weight loss, requiring hospital admission in most cases. In addition to its negative effect on maternal, physical and psychological wellbeing, HG can negatively impact fetal growth and may have adverse consequences on the health of the offspring. HG care and research have been hampered in the past due to stigma, inconsistent diagnostic criteria, mismanagement and lack of investment. Little is known about the nutritional intake of women with HG and whether poor intake at critical stages of pregnancy is associated with perinatal outcomes. Effective treatment requires a combination of medical interventions, lifestyle changes, dietary changes, supportive care and patient education. There is, however, limited evidence-based research on the effectiveness of dietary approaches. Enteral tube feeding and parenteral nutrition are generally reserved for the most intractable cases, where other treatment modalities have failed. Wernicke encephalopathy is a rare but very serious and avoidable consequence of unmanaged HG. A recent priority-setting exercise involving patients, clinicians and researchers highlighted the importance of nutrition research to all. Future research should focus on these priorities to better understand the nutritional implications of HG. Ultimately improved recognition and management of malnutrition in HG is required to prevent complications and optimise nutritional care.

Cannabis Use and the Risk of Cardiovascular Diseases: A Mendelian Randomization Study

Several observational studies have shown that cannabis use has negative effects on the cardiovascular system, but the causality of this relationship has not been confirmed. The aim of the current study was to estimate the effects of genetically determined cannabis use on risk of cardiovascular diseases. Ten single-nucleotide polymorphisms related to cannabis use were employed as instruments to estimate the association between genetically determined cannabis use and risk of cardiovascular diseases using a two-sample Mendelian randomization (MR) method. Summary statistics data on exposure and outcomes were obtained from different genome-wide association meta-analysis studies. The results of this MR analysis showed no causal effects of cannabis use on the risk of several common cardiovascular diseases, including coronary artery disease, myocardial infarction, stroke and ischemic stroke subtypes, atrial fibrillation (AF), and heart failure. Various sensitivity analyses yielded similar results, and no heterogeneity and directional pleiotropy were observed. After adjusting for tobacco use and body mass index, multivariable MR analysis suggested a causal effect of cannabis use on small vessel stroke (SVS) [odds ratio (OR) 1.17; 95% CI 1.02–1.35; p = 0.03] and AF (OR 1.06; 95% CI 1.01–1.10; p = 0.01), respectively. This two-sample MR study did not demonstrate a causal effect of genetic predisposition to cannabis use on several common cardiovascular outcomes. After adjusting for tobacco use and body mass index, the multivariable MR analysis suggested a detrimental effect of cannabis use on the risk of SVS and AF, respectively.

DNA methylation patterns within whole blood of adolescents born from assisted reproductive technology are not different from adolescents born from natural conception

STUDY QUESTION

Do the epigenome-wide DNA methylation profiles of adolescents born from ART differ from the epigenome of naturally conceived counterparts?

SUMMARY ANSWER

No significant differences in the DNA methylation profiles of adolescents born from ART [IVF or ICSI] were observed when compared to their naturally conceived, similar aged counterparts.

WHAT IS KNOWN ALREADY

Short-term and longer-term studies have investigated the general health outcomes of children born from IVF treatment, albeit without common agreement as to the cause and underlying mechanisms of these adverse health findings. Growing evidence suggests that the reported adverse health outcomes in IVF-born offspring might have underlying epigenetic mechanisms.

STUDY DESIGN, SIZE, DURATION

The Growing Up Healthy Study (GUHS) is a prospective study that recruited 303 adolescents and young adults, conceived through ART, to compare various long-term health outcomes and DNA methylation profiles with similar aged counterparts from Generation 2 from the Raine Study. GUHS assessments were conducted between 2013 and 2017. The effect of ART on DNA methylation levels of 231 adolescents mean age 15.96 ± 1.59 years (52.8% male) was compared to 1188 naturally conceived counterparts, 17.25 ± 0.58 years (50.9% male) from the Raine Study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

DNA methylation profiles from a subset of 231 adolescents (13-19.9 years) from the GUHS, generated using the Infinium Methylation Epic Bead Chip (EPIC) array were compared to 1188 profiles from the Raine Study previously measured using the Illumina 450K array. We conducted epigenome-wide association approach (EWAS) and tested for an association between the cohorts applying Firth's bias reduced logistic regression against the outcome of ART versus naturally conceived offspring. Additionally, within the GUHS cohort, we investigated differences in methylation status in fresh versus frozen embryo transfers, cause of infertility as well as IVF versus ICSI conceived offspring. Following the EWAS analysis we investigated nominally significant probes using Gene Set Enrichment Analysis (GSEA) to identify enriched biological pathways. Finally, within GUHS we compared four estimates (Horvath, Hanuum, PhenoAge [Levine], and skin Horvath) of epigenetic age and their correlation with chronological age.

MAIN RESULTS AND THE ROLE OF CHANCE

Between the two cohorts, we did not identify any DNA methylation probes that reached a Bonferroni corrected P-value < 1.24E-0.7. When comparing IVF versus ICSI conceived adolescents within the GUHS cohort, after adjustment for participant age, sex, maternal smoking, multiple births, and batch effect, three methylation probes (cg15016734, cg26744878 and cg20233073) reached a Bonferroni correction of 6.31E-08. After correcting for cell count heterogeneity, two of the aforementioned probes remained significant and an additional two probes (cg 0331628 and cg 20235051) were identified. A general trend towards hypomethylation in the ICSI offspring was observed. All four measures of epigenetic age were highly correlated with chronological age and showed no evidence of accelerated epigenetic aging within their whole blood.

LIMITATIONS, REASONS FOR CAUTION

The small sample size coupled with the use of whole blood, where epigenetic differences may occur in other tissue. This was corrected by the utilized statistical method that accounts for imbalanced sample size between groups and adjusting for cell count heterogeneity. Only a small portion of the methylome was analysed and rare individual differences may be missed.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings provide further reassurance that the effects of the ART manipulations occurring during early embryogenesis, existing in the neonatal period are indeed of a transient nature and do not persist into adolescence. However, we have not excluded that alternative epigenetic mechanisms may be at play.

STUDY FUNDING/COMPETING INTEREST(S)

This project was supported by NHMRC project Grant no. 1042269 and R.J.H. received funding support from Ferring Pharmaceuticals Pty Ltd. R.J.H. is the Medical Director of Fertility Specialists of Western Australia and a shareholder in Western IVF. He has received educational sponsorship from Merck Sharp & Dohme Corp.- Australia, Merck-Serono Australia Pty Ltd and Ferring Pharmaceuticals Pty Ltd. P.B. is the Scientific Director of Concept Fertility Centre, Subiaco, Western Australia. J.L.Y. is the Medical Director of PIVET Medical Centre, Perth, Western Australia. The remaining authors have no conflicts of interest.

Prepregnancy BMI, gestational weight gain and risk of childhood atopic dermatitis: A systematic review and meta-analysis

BACKGROUND

Maternal weight before and during pregnancy influences the health of offspring. Several observational studies have investigated a link between the risk of childhood atopic dermatitis (AD) and prepregnancy maternal body mass index (BMI) and gestational weight gain (GWG), but the conclusions of these studies were inconsistent. The aim of this review was to evaluate the association between the risk of childhood AD and prepregnancy maternal BMI and GWG.

METHODS

The PubMed, Embase, Cochrane, Web of Science, and Scopus databases were searched from inception to February 2, 2021. Observational studies investigating the association between the risk of childhood AD and prepregnancy maternal BMI and GWG were included. Fixed- or random-effects models with inverse variance weights were used to calculate pooled risk estimates. Subgroup analysis and sensitivity analysis were used to explore the sources of heterogeneity.

RESULTS

Thirteen studies with a total of 114 485 participants were included. Ten studies reported prepregnancy maternal BMI, and five reported GWG. Maternal underweight was associated with a higher risk of childhood AD (odds ratio [OR] = 1.06; 95% confidence interval [CI], 1.02-1.10). Continuous BMI was not related to childhood AD (OR = 1.00; 95% CI, 0.98-1.02). In comparison with normal GWG, moderate/very high GWG increased the risk of childhood AD (OR = 1.05; 95% CI, 1.02-1.08; OR = 1.13; 95% CI, 1.07-1.19, respectively), while low GWG decreased the risk (OR = 0.92; 95% CI, 0.89-0.96). Excessive GWG relative to recommendations was associated with a higher risk of childhood AD (OR = 1.05; 95% CI, 1.01-1.10), while a lower risk of childhood AD was associated with inadequate GWG relative to recommendations (OR = 0.87, 95% CI: 0.83-0.91).

CONCLUSIONS

Maternal underweight, high GWG, and excessive GWG relative to recommendations are associated with an elevated risk of childhood AD, while low GWG and inadequate GWG relative to recommendations decreased the risk. Weight management before and during pregnancy is encouraged for primary prevention of childhood AD.

What is known about the nutritional intake of women with Hyperemesis Gravidarum?: A scoping review

Hyperemesis gravidarum (HG) is characterised by extreme nausea and vomiting of pregnancy, which can lead to dehydration, weight loss and electrolyte disturbances. Historically research has been challenging due to a lack of diagnostic criteria and objective outcome measures. Most studies in this population group have focused on medical management of symptoms, with little known about the effect of HG on nutritional intake and how this relates to perinatal outcomes. The aim of this study was to synthesise current knowledge of the dietary intake of women with HG. A systematic search of search engines was conducted in April 2020 using the following databases: MEDLINE, Embase, CINAHL, Cochrane database, Scopus, NHS Evidence, BNI, Emcare, ClinicalTrials.gov, PROSPERO, Ethos and Open Grey. Titles and abstracts were screened independently by two reviewers against predefined inclusion and exclusion criteria. Studies were included where the authors described severe pregnancy nausea and vomiting as HG, regardless of how HG was defined. After removal of duplicates, 4402 titles were identified, of which 3992 were initially excluded based on abstract and title. Following full text review, four of 10 articles were included. Three of the studies were hospital-based case control studies, one was an observational women's cohort study. Assessment of dietary intake was heterogeneous, with both retrospective and prospective self-report methods used, over different timeframes. In three of the studies, dietary intake was reported at one time point only. In total, across all four studies, data from only 314 women were included. Overall, despite data collected from four different countries, over 30 years, with various methods, women with HG had a significantly poorer dietary intake compared to non-affected pregnant women, consuming less than 50 % of recommended intakes for most nutrients. Nutritional intake worsened with increasing severity of symptoms. As this was a scoping review, study quality was not assessed. Overall, this review has identified a paucity of data about the dietary intake of women with HG; the limited available data indicates that women with HG are at risk of malnutrition. Future research quantifying nutritional intake in women with HG at several time points during pregnancy would provide valuable reference data, enabling nutritional status and outcomes to be monitored and interventions to be evaluated.

Relationship between parental overweight and obesity and childhood metabolic syndrome in their offspring: result from a cross-sectional analysis of parent-offspring trios in China

OBJECTIVE

Metabolic syndrome (MS) and its components are observed to emerge in childhood and may continue into adulthood. The study aimed to investigate the association between parental overweight and risk of childhood MS and its components in their offspring.

METHODS

Data were obtained from a cross-sectional survey conducted in Chinese children and adolescents; a total of 11 784 children aged 7-18 years were included in this study; child outcomes were obtained from objective measurements and parental data were obtained from questionnaires; MS was defined according to the modified criteria of Adult Treatment Panel Ⅲ; correlation between parental overweight and offspring MS was assessed via multivariate logistic regression models adjusted for potential covariates.

RESULTS

3476 (29.5%) children were found to have overweight fathers, 1041 (8.8%) had overweight mothers and 852 (7.2%) had both overweight parents. The prevalence of MS was 7.1% in total, 8.2% in boys and 5.9% in girls; children with overweight parents had a higher prevalence of MS and its components (except for elevated glucose) compared with children with normal-weight parents. Children with overweight fathers, mothers and both parents had 2.17 times (95% CI: 1.65-2.85), 2.89 times (95% CI: 2.03-4.11) and 2.81 times (95% CI: 1.91-4.15) higher risk of MS, respectively. Children with overweight mothers were likely to have a higher risk of MS compared with children with overweight fathers. Parental overweight was positively correlated with higher risk of MS, abdominal obesity and low HDL-C both in boys and girls.

CONCLUSION

Parental overweight was strongly associated with increased risk of MS in their offspring, the risk was highest in children with both parents to be overweight. Maternal overweight seems to have a stronger correlation with offspring MS than paternal overweight. Parental overweight is one of the factors for identifying metabolic dysfunction risk in their offspring and other factors need to be considered as well.

Female obesity increases the risk of miscarriage of euploid embryos

OBJECTIVE

To determine whether female body mass index (BMI) is associated with an increased risk of miscarriage after euploid embryo transfer.

DESIGN

A retrospective, observational, multicenter cohort study.

SETTING

University-affiliated in vitro fertilization center.

PATIENT(S)

In this study, 3,480 cycles of in vitro fertilization with preimplantation genetic testing for aneuploidy (PGT-A) in the blastocyst stage and euploid embryo transfer were divided into four groups according to patient BMI.

INTERVENTION(S)

In vitro fertilization with PGT-A.

MAIN OUTCOME MEASURE(S)

The primary outcome was the miscarriage rate, which included both biochemical and clinical miscarriages. Secondary outcomes were implantation, pregnancy, clinical pregnancy, and live birth rates.

RESULT(S)

Cycles were divided into four groups according to BMI (kg/m²): underweight (<18.5; n = 155), normal weight (18.5-24.9; n = 2,549), overweight (25-29.9; n = 591), and obese (≥30; n = 185). The number of PGT-A cycles per patient was similar in the four groups. Fertilization rate, day of embryo biopsy, technique of chromosomal analysis, number of euploid embryos, number of transferred embryos, and method of endometrial preparation for embryo transfer were similar in the four BMI groups. Miscarriage rates were significantly higher in women with obesity compared to women with normal weight, mainly due to a significant increase in the clinical miscarriage rates. Live birth rates also were lower in women with obesity. Obesity in women and day 6 trophectoderm biopsy were found to influence the reduced live birth rate.

CONCLUSION(S)

Women with obesity experience a higher rate of miscarriage after euploid embryo transfer than women with a normal weight, suggesting that other mechanisms than aneuploidy are responsible for this outcome.