You are what your mother eats: evidence for maternal preconception diet influencing foetal sex in humans

Addressing researcher degrees of freedom through minP adjustment

When different researchers study the same research question using the same dataset they may obtain different and potentially even conflicting results. This is because there is often substantial flexibility in researchers' analytical choices, an issue also referred to as "researcher degrees of freedom". Combined with selective reporting of the smallest p-value or largest effect, researcher degrees of freedom may lead to an increased rate of false positive and overoptimistic results. In this paper, we address this issue by formalizing the multiplicity of analysis strategies as a multiple testing problem. As the test statistics of different analysis strategies are usually highly dependent, a naive approach such as the Bonferroni correction is inappropriate because it leads to an unacceptable loss of power. Instead, we propose using the "minP" adjustment method, which takes potential test dependencies into account and approximates the underlying null distribution of the minimal p-value through a permutation-based procedure. This procedure is known to achieve more power than simpler approaches while ensuring a weak control of the family-wise error rate. We illustrate our approach for addressing researcher degrees of freedom by applying it to a study on the impact of perioperative p a O 2 on post-operative complications after neurosurgery. A total of 48 analysis strategies are considered and adjusted using the minP procedure. This approach allows to selectively report the result of the analysis strategy yielding the most convincing evidence, while controlling the type 1 error-and thus the risk of publishing false positive results that may not be replicable.

To adjust or not to adjust in living systematic reviews? It's all about the context

With each update of meta-analyses from living systematic reviews, treatment effects and their confidence intervals are recalculated. This often raises the question whether or not multiplicity is an issue and whether a method to adjust for multiplicity is needed. It seems that answering these questions is not that straightforward. We approach this matter by considering the context of systematic reviews and pointing out existing methods for handling multiplicity in meta-analysis. We conclude that multiplicity is not a relevant issue in living systematic reviews when they are planned with the aim to provide up-to-date evidence, without any direct control on the decision over future research. Multiplicity might be an issue, though, in living systematic reviews designed under a protocol involving a "stopping decision", which can be the case in living guideline development or in reimbursement decisions. Several appropriate methods exist for handling multiplicity in meta-analysis. Existing methods, however, are also associated with several technical and conceptual limitations, and could be improved in future methodological projects. To better decide whether an adjustment for multiplicity is necessary at all, authors and users of living systematic reviews should be aware of the context of the work and question whether there is a dependency between the effect estimates of the living systematic review and its stopping/updating or an influence on future research.

The Impact of Lifestyle on the Secondary Sex Ratio: A Review

The secondary sex ratio (SSR), indicating the ratio of male to female live births, has garnered considerable attention within the realms of reproductive biology and public health. Numerous factors have been posited as potential trendsetters of the SSR. Given the extensive research on the impact of daily behaviors and habits on individuals' reproductive health, there is a plausible suggestion that lifestyle choices may also influence the SSR. By synthesizing the existing literature on the current research field, this comprehensive review indicates that an elevated SSR has been associated with an increased intake of fatty acids and monosaccharides, proper nutrition, higher educational levels, financial prosperity, and favorable housing conditions. On the other hand, a decreased SSR may be linked to undernutrition, socioeconomic disparities, and psychological distress, aligning with the Trivers-Willard hypothesis. Occupational factors, smoking habits, and cultural beliefs could also contribute to trends in the SSR. Our review underscores the significance of considering the aforementioned factors in studies examining the SSR and emphasizes the necessity for further research to unravel the mechanisms underpinning these connections. A more profound comprehension of SSR alterations due to lifestyle holds the potential to adequately develop public health interventions and healthcare strategies to enhance reproductive health and overall well-being.

Digit Ratio (2D:4D; Right-Left 2D:4D) and Multiple Phenotypes for Same-Sex Attraction: The BBC Internet Study Revisited

Same-sex attraction may be linked to low prenatal androgen (in men) and high prenatal androgen (in women). Digit ratio (2D:4D) is thought to be a negative correlate of prenatal androgen and right-left 2D:4D (Dr-l) to reflect lateralized differences in sensitivity to prenatal androgen. Lower 2D:4D has been reported for lesbians compared to heterosexuals, but links to high 2D:4D in gay men are less clear. The largest study thus far (the BBC Internet study) found no significant difference between the 2D:4D of lesbians and heterosexual women but a higher 2D:4D in gay men compared to heterosexual men. Here we consider the possibility that low and high prenatal androgen is associated with same-sex attraction in men (n = 108,779) and women (n = 87,742), resulting in more than two phenotypes. We examined the associations between 2D:4D, Dr-l, and same-sex attraction scores in the BBC Internet study. In contrast to the earlier report, which considered sexual orientation in categories, there were positive linear associations in men (right and left 2D:4D, but not Dr-l) and negative linear associations in women (right 2D:4D and Dr-l, but not left 2D:4D). There were no curvilinear relationships for right and left 2D:4D. However, Dr-l showed a U-shaped association with same-sex attraction in men. Thus, (1) high prenatal androgen may be implicated in female homosexuality, while both low and high prenatal androgen may be implicated in male homosexuality, and (2) large side differences in sensitivity to androgen may be associated with elevated same-sex attraction in men.

Divergences in sex ratio at birth in US Census Regions due to racial factors: chronic stress and female foeticide

OBJECTIVES

The sex ratio of live births (males/total [M/T]) approximates 0.515. Many factors reduce M/T, and these include stress. Antenatal sexing is used for female foeticide in the setting of male offspring preference. Regional differences and latitude gradients in M/T also occur. This study analysed M/T in the US by Census Regions.

STUDY DESIGN

This was an ecological study.

METHODS

Live births by sex, Census region, state and mother's race were obtained from CDC Wonder (2007-2020).

RESULTS

There were 55,453,437 births (M/T 0.5116, 95% confidence interval: 0.5115-0.5118). M/T was Black/African American < Indian/Alaska Native American < White < Asian (P<<0.0001). M/T was significantly lowest in South and highest in West. The South had the lowest proportion of Asian/Pacific Islander births (3.9%) and the highest proportion of Black/African American (21.9%). West has the highest proportion of Asian/Pacific Islander (11.2%) and the lowest proportion of Black/African American births (5.3%). In Asian/Pacific Islander births, M/T significantly rose to third order and fell to sixth order births, unlike the other races that showed a decline from the first order.

CONCLUSIONS

Asian M/T may be elevated because of male offspring preference and selective female foeticide. M/T may be depressed in Black and American Indian/Alaskan births due to chronic stress, as race remains the most important factor associated with wealth inequality in the United States. The lower M/T of these two races when compared with White equates to a constant loss of 4.13 and 2.55/1000 male births. The higher Asian M implies a chronic loss of 3.78 females per 1000 births. Both have public health implications.

The Role of Maternal Preconception Adiposity in Human Offspring Sex and Sex Ratio

We evaluated relationships between preconception adiposity and human offspring sex and sex ratio. Using data from a prospective preconception cohort nested within a randomized controlled trial based at 4 US clinical sites (2006-2012), we used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for male:female sex ratio, and log-identity regression to estimate risk differences (RDs) and 95% CIs for male and female livebirth according to preconception adiposity measures. Inverse-probability weights accounted for potential selection bias. Among 603 women attempting pregnancy, there were meaningful reductions in sex ratio for the highest category of each adiposity measure. The lowest sex ratios were observed for obesity (body mass index of ≥30, calculated as weight (kg)/height (m)2, OR = 0.48, 95% CI: 0.26, 0.88) relative to normal body mass index, and the top tertiles (tertile 3) of serum leptin (OR = 0.50, 95% CI: 0.32, 0.80) and skinfold measurements (OR = 0.50, 95% CI: 0.32, 0.79) relative to the lowest tertiles. Reductions were driven by 11-15 fewer male livebirths per 100 women (for obesity, RD = -15, 95% CI: -23, -6.7; for leptin tertile 3, RD = -11, 95% CI: -20, -3.2; and for skinfolds tertile 3, RD = -11, 95% CI: -19, -3.3). We found that relationships between preconception adiposity measures and reduced sex ratio were driven by a reduction in male births.

Can helminth and malaria infections affect sex ratio at birth in sub-Saharan Africa? Ideas and hypothesis

The sex ratio (ratio of boys to girls) at birth (SRB) is about 1.05 (about 105 males to 100 females) under normal conditions and could be an indicator for monitoring demographic changes. Generally, in comparison with female fetuses, the male fetus is biologically weaker and more vulnerable to prenatal events. SRB is influenced by various factors, such as maternal malnourishment. Remarkably, maternal malnourishment and less energy intake are pivotal factors for declining SRB in humans. As estimates, the SRB is below the normal range in sub-Saharan Africa (1.03) than the normal range (1.05). On the other hand, both malaria and helminth infections are hyperendemic in sub-Saharan Africa and both diseases are associated with maternal malnourishment. Hence, an important question arises, could declining SRB in sub-Saharan Africa be influenced by malaria and helminth infections? Cumulative evidence suggests that malaria and helminth infections could influence SRB by induction of maternal malnourishment. This hypothesis provides new ideas about the variation of SRB in some regions of the world where helminths and malaria are endemic.

Differences in maternal and early child nutritional status by offspring sex in lowland Nepal

OBJECTIVE

On average, boys grow faster than girls in early life but appear more susceptible to undernutrition. We investigated sex differences in early child growth, and whether maternal nutritional status and diet differed by offspring sex during and after pregnancy in an undernourished population.

METHODS

We analyzed longitudinal data from a cluster-randomized trial from plains Nepal, stratifying results by child or gestational age. Children's outcomes (0-20 months) were weight, length, and head circumference and their z-scores relative to WHO reference data in 2-monthly intervals (n range: 24837 to 25 946). Maternal outcomes were mid-upper arm circumference (MUAC), and body mass index (BMI) during pregnancy (12-40 weeks) (n = 5550 and n = 5519) and postpartum (n = 15 710 and n = 15 356), and diet in pregnancy. We fitted unadjusted and adjusted mixed-effects linear and logistic regression models comparing boys with girls.

RESULTS

Boys were larger than girls, however relative to their sex-specific reference they had lower length and head circumference z-scores from birth to 12 months, but higher weight-for-length z-scores from 0 to 6 months. Mothers of sons had higher MUAC and BMI around 36 weeks gestation but no other differences in pregnancy diets or pregnancy/postpartum maternal anthropometry were detected. Larger sex differences in children's size in the food supplementation study arm suggest that food restriction in pregnancy may limit fetal growth of boys more than girls.

CONCLUSIONS

Generally, mothers' anthropometry and dietary intake do not differ according to offspring sex. As boys are consistently larger, we expect that poor maternal nutritional status may compromise their growth more than girls. Copyright © 2021 John Wiley & Sons, Ltd.

Outcomes for infants whose mothers had an eating disorder in the perinatal period: A systematic review of the evidence

OBJECTIVE

To establish any health outcomes for infants to age one, associated with their mother having a diagnosis of an active eating disorder during pregnancy or the 12-month postnatal period.

METHOD

A qualitative systematic literature review of numerous databases (Medline, PsycINFO, CINAHL, Scopus, Cochrane Library, MedNar, PsycExtra, National Institute for Health and Care Excellence and Open Grey) was performed examining any infant health outcomes.

RESULTS

This resulted in 22 included studies (17 cohort, 3 cross-sectional, 1 case controlled and 1 mixed methods study). A range of adverse infant outcomes including poor birth, growth and interactional feeding outcomes were identified.

DISCUSSION

Antenatal identification and treatment for women with an eating disorder during the perinatal period and their infants are vital. Optimizing pregnancy nutrition, maternal eating disorder symptoms and feeding interactions appear particularly important.

Sexual dimorphisms in brain gene expression in the growth-restricted guinea pig can be modulated with intra-placental therapy

BACKGROUND

Fetal responses to adverse pregnancy environments are sex-specific. In fetal guinea pigs (GPs), we assessed morphology and messenger RNA (mRNA) expression in fetal growth-restricted (FGR) tissues at midpregnancy.

METHODS

Female GPs were assigned either an ad libitum diet (C) or 30% restricted diet (R) prior to pregnancy to midpregnancy. At midpregnancy, a subset of R females underwent ultrasound-guided nanoparticle (NP) injection to enhance placental function. Five days later, fetuses were sampled. Fetal brain, heart, and liver were assessed for morphology (hematoxylin and eosin), proliferation (Ki67), and vascularization (CD31), as well as expression of inflammatory markers.

RESULTS

R fetuses were 19% lighter with reduced organ weights and evidence of brain sparing compared to controls. No increased necrosis, proliferation, or vascularization was found between C and R nor male or female fetal organs. Sexual dimorphism in mRNA expression of Tgfβ and Ctgf was observed in R but not C fetal brains: increased expression in females. NP treatment increased fetal brain mRNA expression of Tgfβ and Ctgf in R males, abolishing the significant difference observed in untreated R fetuses.

CONCLUSIONS

Sex-specific differences in mRNA expression in the fetal brain with FGR could impart a potential survival bias and may be useful for the development of treatments for obstetric diseases.

IMPACT

Male and female fetuses respond differently to adverse pregnancy environments. Under fetal growth restriction conditions, inflammatory marker mRNA expression in the fetal brain was higher in females compared to males. Differences in gene expression between males and females may confer a selective advantage/disadvantage under adverse conditions. Better characterization of sexual dimorphism in fetal development will aid better development of treatments for obstetric diseases.

Relationship between Selected Trace Elements in Human Milk and Psychosocial Characteristics in Korean Early Postpartum Women

This study aimed to identify the relationship between selected trace elements in human milk and depression, breastfeeding self-efficacy, sleep satisfaction, and the demographic and obstetric characteristics of lactating mothers. Forty lactating mothers recovering after birth in two postpartum care centers located in Changwon, South Korea, were studied. Calcium, sodium, iron, and selenium concentrations in human milk were analyzed using inductively coupled plasma mass spectrometry at the analysis center of Kyungnam University. Data were analyzed using descriptive statistics, the Kruskal-Wallis test, the Mann-Whiney U test, and Spearman's correlation coefficients using an SPSS 23.0 program. There were no significant differences in concentration of selected trace elements (calcium, sodium, iron, and selenium) in human milk according to demographic and obstetric characteristics. Sodium concentration was negatively correlated with breastfeeding self-efficacy (r = -0.51, CI = -0.71 to -0.24). Selenium concentration was negatively correlated with calcium concentration (r = -0.34, CI = -0.58 to 0.38). Postpartum depression was negatively correlated with sleep satisfaction (r = -0.46, CI = -0.67 to -0.17) and with breastfeeding self-efficacy (r = -0.41, CI = -0.64 to -0.11). Breastfeeding self-efficacy was positively correlated with sleep satisfaction (r = 0.48, CI = 0.20 to 0.69). This study suggests that sodium concentration in human milk is associated with breastfeeding self-efficacy.

The Role of Offspring Genotype-By-Sex Interactions, Independently of Environmental Cues, on the Phenotype Traits of an Obese Swine Model

Simple Summary

The present study, comparing the postnatal development of purebred Iberian and crossbreds Iberian × Large White littermates born from purebred Iberian sows, allows us to discern phenotype traits driven by the genotype from features imposed by pre- and postnatal environment. The results obtained in this study support the well-known relevance of genotype but also evidence a paramount role of the interaction sex-by-genotype, with differential effects depending on the offspring genotype and sex.

Abstract

The present study aimed to assess the importance of offspring genotype on postnatal development, independently of confounding factors related to prenatal environment and postnatal lifestyle, using a translational model of obesity and metabolic syndrome (the Iberian pig). Hence, we compared two genotypes (purebred Iberian and crossbreds Iberian × Large White), produced in one single maternal environment (pure Iberian mothers) through artificial insemination of Iberian sows with Iberian and Large White heterospermic semen and maintained in the same conditions during postnatal development. The results indicate that, under same pre- and postnatal environments, the interaction genotype-by-sex has a determinant role on offspring phenotype (i.e., growth and development, metabolic and antioxidant status and fatty acid composition of different tissues). These results may set the basis for future preclinical and clinical research on the differences in the metabolic phenotype among genotypes.

Sex differences in foetal origins of child emotional symptoms: a test of evolutionary hypotheses in a large, general population cohort

BACKGROUND

Based on previous findings from the Wirral Child Health and Development Study (WCHADS), and on evolutionary hypotheses, we preregistered analyses of data from a large epidemiological sample (https://osf.io/fn5g9/register/564d31db8c5e4a7c9694b2be), to test for sex-dependent moderation by prenatal maternal depressive symptoms of the association between postnatal maternal depressive symptoms and child emotional problems.

METHODS

A total of 8,354 mothers and children were followed from pregnancy to 3.5 years in the Avon Longitudinal Study of Parents and Children (ALSPAC). Self-report measures of prenatal and postnatal maternal depressive symptoms, and maternal report of child emotional symptoms were administered.

RESULTS

There was a three-way interaction between maternal prenatal and postnatal depression, and child sex (Coeff .042 95% CI 0.015 to 0.068, p = .002). This arose from moderation by prenatal depression, in opposite directions in boys and in girls. In boys, the association between postnatal depression and child emotional symptoms was weaker following lower prenatal depressive symptoms (interaction term coeff = .030, p = .001), and in girls, to a lesser extent, the association was stronger following lower prenatal depressive symptoms (interaction term coeff = -.012, p = .221).

CONCLUSIONS

We replicated the finding from the WCHADS that prenatal depression modifies the association between postnatal depression and children's emotional problems in a sex-dependent fashion. In ALSPAC, the sex difference was explained mainly by a protective effect of low prenatal depression in boys, while in WCHADS, it arose from greater vulnerability of girls to postnatal depression following low prenatal depression. In the light of these findings, in evaluating and implementing early interventions, there is need to consider that risks associated with postnatal depression may vary depending on maternal mood during pregnancy and may differ between boys and girls.

Sex ratios at birth vary with environmental harshness but not maternal condition

The sex ratio at birth (SRB) may be patterned by maternal condition and/or environmental stressors. However, despite decades of research, empirical results from across the social and biological sciences are equivocal on this topic. Using longitudinal individual-level data from a US population during the interwar period (1918-1939), inclusive of three distinct eras (Spanish Flu, Roaring '20 s, and the Great Depression), we evaluate predictions from two theoretical frameworks used to study patterning in SRB - (1) 'frail males' and (2) adaptive sex-biased investment theory (Trivers-Willard). The first approach centers on greater male susceptibility to exogenous stressors and argues that offspring survival should be expected to differ between 'good' and 'bad' times. The second approach contends that mothers themselves play a direct role in manipulating offspring SRB, and that those in better condition should invest more in sons. In-line with 'frail male' predictions, we find that boys are less likely to be born during the environmentally challenging times of the Spanish Flu and Great Depression. However, we find no evidence that maternal condition is associated with sex ratios at birth, a result inconsistent with the Trivers-Willard hypothesis.

Biological, environmental and socioeconomic determinants of the human birth sex ratio in the Czech Republic

The Trivers-Willard Hypothesis (TWH) states that parents in good conditions bias the sex ratio towards sons and parents in poor conditions bias the sex ratio towards daughters. This study used data from a large nationwide population dataset (N=1,401,851) from the Czech Republic - a modern contemporary society. The study included air pollution and property prices in the TWH estimation, and had a more detailed focus on stillbirths than previous studies. Using official natality microdata from the Czech Statistical Office for years between 1992 and 2010 and data on levels of air pollution in the country over the same period, the study assessed whether the biological and socioeconomic status of mothers and environmental factors affected the sex of children. The results were largely insignificant and not robust across specifications. The presented epidemiological evidence suggests that stillbirths are randomly distributed in the Czech Republic and that the sex ratio is not affected by the socioeconomic status of mothers or by environmental characteristics.

Elevated maternal linoleic acid reduces circulating leptin concentrations, cholesterol levels and male fetal survival in a rat model

KEY POINTS

Linoleic acid consumption is increasing in Western populations. We investigated whether elevated linoleic acid in pregnancy was deleterious to mothers or offspring. Maternal and fetal body and organ weights were not affected by elevated linoleic acid consumption. Maternal lipids and leptin were altered following elevated linoleic acid consumption. Male offspring numbers were reduced following elevated linoleic acid consumption.

ABSTRACT

Dietary intakes of linoleic acid (LA) have increased dramatically in Western populations, including in women of reproductive age. Pro-inflammatory effects of LA may have detrimental effects on maternal and offspring outcomes. We aimed to investigate whether consumption of a maternal diet with elevated LA altered maternal inflammatory or metabolic markers during pregnancy, fetal growth and/or the sex ratio of the offspring. Female Wistar Kyoto rats consumed a diet high in LA (HLA) (6.21% of energy) or a diet low in LA (LLA) (1.44% of energy) for 10 weeks prior to mating and during pregnancy. Pregnant rats were killed at embryonic day 20 (E20). There were no differences in maternal or fetal body weights or organ weights in the HLA group compared to the LLA group. There was no difference in maternal circulating cytokine concentrations between dietary groups. In the maternal liver, IL-1α concentrations were significantly lower, and TNF-α and IL-7 significantly higher in the HLA group. Total plasma cholesterol, LDL-cholesterol, HDL cholesterol and the total:HDL cholesterol ratio were lower in dams fed the HLA diet. mRNA expression of sterol regulatory element binding transcription factor 1 (SREBF-1) and leptin in maternal adipose tissue was lower in the HLA group, as were circulating leptin concentrations. The proportion of male fetuses was lower and circulating prostaglandin E metabolite concentrations were increased in the HLA group. In conclusion, consumption of a maternal diet high in linoleic acid alters cholesterol metabolism and prostaglandin E metabolite concentrations, which may contribute to the reduced proportion of male offspring.

Maternal factors contributing to low birth weight deliveries in Tshwane District, South Africa

BACKGROUND

Low birth weight continues to be a main cause of child morbidity and mortality. Low birth weight can cause complications in adult life, and is therefore a public health concern. In this study, we determined the maternal factors that contribute to low birth weight (LBW) deliveries in Tshwane District, South Africa.

METHODS

We conducted a case control study of 1073 randomly selected mothers who delivered babies in four hospitals in the district. We reviewed antenatal and maternity registers to obtain information about the mothers and their offspring. We fitted a multiple logistic regression to examine relationships between possible factors associated with LBW.

RESULTS

From the total sample of mothers (n = 1073), 77% (n = 824) were adult women, aged 20 to 35 years. Of the adult mothers, 38.54% (n = 412) delivered low birth weight (LBW) infants. The mean gestational age and weight of all infants at birth was 37.16 weeks (SD 2.92) and 2675.48 grams (SD 616.16) respectively. LBW was associated with prematurity, odds ratio (OR) 7.15, 95% confidence interval (CI) 5.18 to 9.89; premature rupture of membranes OR 7.33, 95% CI 2.43 to 22.12 and attending fewer than five antenatal care (ANC) visits OR 1.30, 95% CI 1.06 to 1.61. Male infants were less likely to be LBW, in this population.

CONCLUSION

Women who attended fewer than five ANC visits were predisposed to give birth to low birth weight babies. Mothers should be encouraged to attend ANC visits to detect adverse events like premature rupture of membranes and premature labour timeously.

Dosage Compensation and Gene Expression of the X Chromosome in Sheep

Ohno's hypothesis predicts that the expression of the single X chromosome in males needs compensatory upregulation to balance its dosage with that of the diploid autosomes. Additionally, X chromosome inactivation ensures that quadruple expression of the two X chromosomes is avoided in females. These mechanisms have been actively studied in mice and humans but lag behind in domestic species. Using RNA sequencing data, we analyzed the X chromosome upregulation in sheep fetal tissues from day 135 of gestation under control, over or restricted maternal diets (100%, 140% and 60% of National Research Council Total Digestible Nutrients), and in conceptuses, juvenile, and adult somatic tissues. By computing the mean expression ratio of all X-linked genes to all autosomal genes (X:A), we found that all samples displayed some levels of X chromosome upregulation. The degrees of X upregulation were not significant (P-value = 0.74) between ovine females and males in the same somatic tissues. Brain, however, displayed complete X upregulation. Interestingly, the male and female reproduction-related tissues exhibited divergent X dosage upregulation. Moreover, expression upregulation of the X chromosome in fetal tissues was not affected by maternal diets. Maternal nutrition, however, did change expression levels of several X-linked genes, such as sex determination genes SOX3 and NR0B1 In summary, our results showed that X chromosome upregulation occurred in nearly all sheep somatic tissues analyzed, thus support Ohno's hypothesis in a new species. However, the levels of upregulation differed by different subgroups of genes such as those that are house-keeping and "dosage-sensitive".

Maternal hand grip strength in pregnancy, newborn sex and birth weight

AIM

Hand grip strength (HGS) is a non-invasive measure of physical strength, overall health, and nutritional status. The aim of the study was to test if HGS and its changes in pregnancy are related with offspring sex and birth weight.

METHODS

We conducted longitudinal study on 95 healthy pregnant women (mean age 29.57 ± 3.43). HGS was measured in each trimester. A woman's height and changes in weight in pregnancy were also measured. The information on a child's sex, birth weight and the pregnancy week at delivery were derived from hospital records. Fifty one women delivered a boy, and forty four women delivered a girl.

RESULTS

HGS decreased from the first to the third trimester of pregnancy (F(2,188) = 15.94, p < 0.001). Women with greater HGS in each trimester were more likely to give birth to a boy (p < 0.05), and the decrease in HGS in pregnancy was comparable in the two groups of mothers (F(2,186) = 1.39, p = 0.25). HGS in pregnancy was related with offspring birth weight when controlled for a child's sex and week at delivery (F(2,182) = 3.15, p = 0.04). Maternal height also important predictor of HGS in pregnancy, and the decrease in HGS was only observed in shorter women.

CONCLUSION

The results of this study indicate that HGS is a sensitive marker, differentiating the variation in physical condition in healthy, well-fed pregnant women in affluent population and pregnancy outcome (offspring sex and birth weight). Also, the result indicates that relatively taller women bear lower cost of pregnancy and are able to invest more in developing foetus.

Polyunsaturated fatty acids influence offspring sex ratio in cows

Dietary polyunsaturated fatty acids (PUFAs) can influence fertility in farm animals. Some evidence in mice and sheep have suggested that PUFAs may influence offspring sex ratio, which may have significant value for cattle production. To test this hypothesis, three groups of Holstein cows were supplemented with either 0%, 3% or 5% protected fat (PF) in the form of calcium salt of fatty acids (rich in omega-6) from 14–21 days pre-partum until conception. Proven-fertile frozen semen from the same ejaculate was used for insemination. Calf sex recorded at birth was 8/19 (42.1%) male offspring in the control group, increasing to 14/20 (70%, P > 0.05) and 17/20 (85%, P < 0.05) in 3% and 5% PF, respectively. To test if this effect was caused by a direct influence on the oocyte, we supplemented bovine cumulus oocyte complexes during in vitro maturation with either omega-3 alpha-linolenic acid (ALA), omega-6 linoleic acid (LA) or trans-10, cis-12 conjugated linoleic acid (CLA). Sex ratio of the produced transferable embryos was determined using PCR of SRY gene. Similar to the in vivo results, sex ratio was skewed to the male side in the embryos derived from LA- and CLA-treated oocytes (79% and 71%) compared to control and ALA-treated oocytes (44% and 54%, respectively). These results indicate that both dietary and in vitro supplementation of omega-6 PUFAs can skew the sex ratio towards the male side in cattle. Further experiments are required to confirm this effect on a larger scale and to study the mechanisms of action that might be involved.

Pregravid hypertension may have different secondary sex ratio effects in different races in the United States

BACKGROUND

Males are born in excess of females and the ratio is expressed as M/F (male/female births=secondary sex ratio, also known as secondary sex ratio). This is expected to approximate 1.048. Racial M/F disparities are known. A recent study in China showed that pregravid systolic hypertension is higher in women who delivered a boy than in those who had a girl. This study was carried out in order to identify the effect of pregravid hypertension in the United States on M/F by race.

METHODS

Monthly male and female live births by race for the entire US along with the presence/absence of hypertension were obtained from the website of the Centers for Disease Control and Prevention for 2007-2015 for the four racial groups: American Indian or Alaska Native, Asian or Pacific Islander, Black or African American and White.

RESULTS

This study analysed 36,364,253 live births. For White births, mothers who had chronic hypertension were likelier to have male than female offspring when compared to non-hypertensives (p=0.003). Conversely, Black or African American mothers who had hypertension were less likely to have male than female offspring when compared to non-hypertensives (p=0.022). There were F differences for/F differences for the presence or absence of hypertension for the other two races or for the total.

CONCLUSIONS

It is possible that hypothesised innate interracial periconceptual hormonal differences may modulate M/F responses to hypertension in different races.

Education Gains Attributable to Fertility Decline: Patterns by Gender, Period, and Country in Latin America and Asia

We investigate the heterogeneity across countries and time in the relationship between mother's fertility and children's educational attainment-the quantity-quality (Q-Q) trade-off-by using census data from 17 countries in Asia and Latin America, with data from each country spanning multiple census years. For each country-year, we estimate micro-level instrumental variables models predicting secondary school attainment using number of siblings of the child, instrumented by the sex composition of the first two births in the family. We then analyze correlates of Q-Q trade-off patterns across countries. On average, one additional sibling in the family reduces the probability of secondary education by 6 percentage points for girls and 4 percentage points for boys. This Q-Q trade-off is significantly associated with the level of son preference, slightly decreasing over time and with fertility, but it does not significantly differ by educational level of the country.

Live birth sex ratios and father's geographic origins in Jerusalem, 1964-1976

OBJECTIVE

To examine whether ancestry influenced sex ratios of offspring in a birth cohort before parental antenatal sex selection influenced offspring sex.

METHODS

We measured the sex ratio as the percent of males according to countries of birth of paternal and maternal grandfathers in 91,459 live births from 1964 to 1976 in the Jerusalem Perinatal Study. Confidence limits (CI) were computed based on an expected sex ratio of 1.05, which is 51.4% male.

RESULTS

Of all live births recorded, 51.4% were male. Relative to Jewish ancestry (51.4% males), significantly more males (1,761) were born to Muslim ancestry (54.5, 95% CI = 52.1-56.8, P = 0.01). Among the former, sex ratios were not significantly associated with paternal or maternal age, education, or offspring's birth order. Consistent with a preference for male offspring, the sex ratio decreased despite increasing numbers of births over the 13-year period. Sex ratios were not affected by maternal or paternal origins in North Africa or Europe. However, the offspring whose paternal grandfathers were born in Western Asia included fewer males than expected (50.7, 50.1-51.3, P = 0.02), whether the father was born abroad (50.7) or in Israel (50.8). This was observed for descendents of paternal grandfathers born in Lebanon (47.6), Turkey (49.9), Yemen & Aden (50.2), Iraq (50.5), Afghanistan (50.5), Syria (50.6), and Cyprus (50.7); but not for those from India (51.5) or Iran (51.9). The West Asian group showed the strongest decline in sex ratios with increasing paternal family size.

CONCLUSIONS

A decreased sex ratio associated with ancestry in Western Asia is consistent with reduced ability to bear sons by a subset of Jewish men in the Jerusalem cohort. Lower sex ratios may be because of pregnancy stress, which may be higher in this subgroup. Alternatively, a degrading Y chromosome haplogroup or other genetic or epigenetic differences on male germ lines could affect birth ratios, such as differential exposure to an environmental agent, dietary differences, or stress. Differential stopping behaviors that favor additional pregnancies following the birth of a daughter might exacerbate these lower sex ratios.

Maternal Blood Pressure Before Pregnancy and Sex of the Baby: A Prospective Preconception Cohort Study

BACKGROUND

Population-level sociologic studies have suggested that adverse societal conditions may affect fetal viability in a sex-specific manner and thereby modify the ratio of male vs. female babies. This concept suggests that there may exist certain physiologic features in a woman that relate to her likelihood of delivering a boy or girl. We thus established a preconception cohort to prospectively evaluate the relationship between maternal pregravid health and sex of the baby.

METHODS

In this analysis nested within an observational cohort study, 1,411 newly married women in Liuyang, China, underwent pregravid cardiometabolic characterization (including anthropometry and measurement of blood pressure, cholesterol, triglycerides, and glucose) at median 26.3 weeks before a singleton pregnancy, delivering at 39.0 ± 1.3 weeks gestation.

RESULTS

Systolic blood pressure before pregnancy was higher in women who delivered a boy than in those who had a girl (112.5 ± 11.9 vs. 109.6 ± 12.0 mm Hg, P < 0.0001). The prevalence of a male baby progressively increased across quintiles of pregravid systolic blood pressure (P < 0.0001). After covariate adjustment, mean adjusted pregravid systolic blood pressure was higher in mothers of boys vs. girls (106.0 vs. 103.3 mm Hg, P = 0.0015). On logistic regression analysis, pregravid systolic blood pressure emerged as the only significant predictor of having a male baby (adjusted odds ratio = 1.017 per mm Hg, 95% confidence interval = 1.007-1.028). The pregravid difference in blood pressure between mothers of boys and girls was not present during any trimester of pregnancy.

CONCLUSION

Maternal blood pressure before pregnancy is a previously unrecognized factor that may be associated with the likelihood of delivering a boy or girl.

Evidence of socio-economic stress and female foeticide in racial disparities in the gender ratio at birth in the United States (1995-2014)

BACKGROUND

Males are born in excess of females, expressed as M/T (male/total births), which is expected to approximate 0.515. Racial M/T disparities have been long known. This study was carried out in order to identify such disparities in different races in the United States.

DESIGN

Monthly male and female live births by race for the entire US were obtained from the website of the Centers for Disease Control and Prevention for 1995-2014 for the four racial groups: American Indian or Alaska Native, Asian or Pacific Islander, Black or African American and White.

RESULTS

This study analysed 80805992 live births (M/T 0.5117). M/T was Asian or Pacific Islander>White>American Indian or Alaska Native>Black or African American. The M/T gradient across races was highly significant (p<0.0001).

CONCLUSIONS

The perinatal mortality rate is an important indicator of quality of health care delivery and is expected to approximate 6/1000 births. M/T declines in association with surrogates of socioeconomic status, presumably due to higher stress levels. The lower baseline M/T of Indian or Alaska Native and Black and African American is equivalent to a constant reduction of 3.5-4/1000 male births when compared to White M/T. Race is the most significant variable associated with wealth inequality in the US and may be partially responsible. Sex-selective abortion and the application of a male offspring preference stopping rule is widespread in Asia its immigrants, and in this study is equivalent a constant loss of 3.5 females foetuses per 1000 live births when compared to Whites.

Sex ratio at birth is associated with type 1 diabetes characteristics

AIMS

To assess the association between maternal diabetes characteristics and sex ratio at birth (SRB) in women with type 1 diabetes mellitus.

METHODS

We performed a case-control study. The study subjects were infants born alive to women with type 1 diabetes and singleton pregnancies. Cases and controls were defined as male and female newborns, respectively. SRB was analysed according to diabetes-related characteristics adjusting in a logistic regression analysis for maternal characteristics known to affect SRB in the general population.

RESULTS

The observed SRB (238 males/468 live births = 0.509) did not differ from the expected. In the logistic regression analysis, SRB was significantly associated with three diabetes characteristics: (1) diabetes duration, with odds ratios (ORs) for a live male newborn = 1.22 (95 % confidence interval (CI), 0.66-2.24 for ≤5 years, OR 2.79 (95 % CI 1.36-5.74) for >20 years; (2) mean first-trimester glycated haemoglobin, with OR 1.98 (95 % CI 1.09-3.62) for ≤6.7 % (50 mmol/mol) and OR 2.61 (95 % CI 1.16-5.85) for >8.2 % (66 mmol/mol) and (3) mean first-trimester insulin dose, with OR 0.70 (95 % CI 0.36-1.38) for ≤0.5 IU/kg/day and OR 0.18 (95 % CI 0.05-0.59) for >1.0 IU/kg/day.

CONCLUSIONS

We conclude that SRB in this cohort is independently associated with three diabetes characteristics. These associations are to be confirmed.

Birth Month and Cardiovascular Disease Risk Association: Is meaningfulness in the eye of the beholder?

In the modern era, with high-throughput technology and large data size, associational studies are actively being generated. Some have statistical and clinical validity and utility, or at least have biologically plausible relationships, while others may not. Recently, the potential effect of birth month on lifetime disease risks has been studied in a phenome-wide model. We evaluated the associations between birth month and 5 cardiovascular disease-related outcomes in an independent registry of 8,346 patients from Ontario, Canada in 1977-2014. We used descriptive statistics and logistic regression, along with model-fit and discrimination statistics. Hypertension and coronary heart disease (of primary interest) were most prevalent in those who were born in January and April, respectively, as observed in the previous study. Other outcomes showed weak or opposite associations. Ancillary analyses (based on raw blood pressures and subgroup analyses by sex) demonstrated inconsistent patterns and high randomness. Our study was based on a high risk population and could not provide scientific explanations. As scientific values and clinical implications can be different, readers are encouraged to read the original and our papers together for more objective interpretations of the potential impact of birth month on individual and public health as well as toward cumulative/total evidence in general.

Obesity epidemic: impact from preconception to postpartum

The obesity epidemic is on the rise throughout the USA and the world. Not only does it affect the general population but it also specifically poses unique threats to a woman’s life in the antepartum, peripartum and postpartum periods. An increased BMI is associated with worse perinatal outcomes, including higher rates of preeclampsia (and other hypertensive disorders), macrosomia, other neonatal morbidities and gestational diabetes. Isolated maternal obesity and additional maternal diabetes predispose the infant to potential adult disease through fetal programming. This review of the literature examines the effects of obesity on a woman’s life, outlining complications beginning with preconception through the postpartum period.

Lay abstract: The obesity epidemic poses unique threats during the whole cycle of pregnancy. This review examines the effects of obesity on a woman’s life, outlining complications from prior to conception through the postpartum period. In addition, the contributions to adult disease of fetal exposure to this maternal risk are discussed. Future advances in nanotechnology and better understanding of placental function might allow more options in preventative and therapeutic interventions, yet with minimal fetal risk.

Changes in Income at Macro Level Predict Sex Ratio at Birth in OECD Countries

The human sex ratio at birth (SRB) is approximately 107 boys for every 100 girls. SRB was rising until the World War II and has been declining slightly after the 1950s in several industrial countries. Recent studies have shown that SRB varies according to exposure to disasters and socioeconomic conditions. However, it remains unknown whether changes in SRB can be explained by observable macro-level socioeconomic variables across multiple years and countries. Here we show that changes in disposable income at the macro level positively predict SRB in OECD countries. A one standard deviation increase in the change of disposable income is associated with an increase of 1.03 male births per 1000 female births. The relationship is possibly nonlinear and driven by extreme changes. The association varies from country to country being particular strong in Estonia. This is the first evidence to show that economic and social conditions are connected to SRB across countries at the macro level. This calls for further research on the effects of societal conditions on general characteristics at birth.

Bayesian Inference on Predictors of Sex of the Baby

It is well known that the sex ratio at birth is a biological constant, being about 106 boys to 100 girls. However couples have always wanted to know and decide in advance the sex of a newborn. For example, a large number of papers appeared connecting biometrical variables, such as length of follicular phase in the woman menstrual cycle or timing of intercourse acts to the sex of new baby. In this paper, we propose a Bayesian model to validate some of these theories by using an independent database. Results show that we could not show an effect of the follicular length on the sex of the baby. We also obtain a slightly larger probability, although not significant, of conceiving a female just after the mucus peak day.

Do differences in Toxoplasma prevalence influence global variation in secondary sex ratio? Preliminary ecological regression study

Sex of the fetus is genetically determined such that an equal number of sons and daughters are born in large populations. However, the ratio of female to male births across human populations varies significantly. Many factors have been implicated in this. The theory that natural selection should favour female offspring under suboptimal environmental conditions implies that pathogens may affect secondary sex ratio (ratio of male to female births). Using regression models containing 13 potential confounding factors, we have found that variation of the secondary sex ratio can be predicted by seroprevalence of Toxoplasma across 94 populations distributed across African, American, Asian and European continents. Toxoplasma seroprevalence was the third strongest predictor of secondary sex ratio, β = −0·097, P < 0·01, after son preference, β = 0·261, P < 0·05, and fertility, β = −0·145, P < 0·001. Our preliminary results suggest that Toxoplasma gondii infection could be one of the most important environmental factors influencing the global variation of offspring sex ratio in humans. The effect of latent toxoplasmosis on public health could be much more serious than it is usually supposed to be.

Increased proportion of female lambs by feeding Border Leicester × Merino ewes a diet high in omega-6 fatty acids around mating

The proportion of female lambs was previously higher when ewes were offered a diet high in omega-6 fatty acids (n-6) based on oats and cottonseed meal (oats/CSM) around joining. The effect of the length of time of feeding the high n-6 diet on the sex ratio of lambs has not previously been reported. The aim of the present study was to determine whether the proportion of female lambs was higher when Border Leicester × Merino ewes were fed a diet high in n-6 either pre-conception only or both pre- and post-conception. Ewes were fed a low n-6 diet based on silage or a high n-6 diet based on oats/CSM for 40 days pre-mating until the end of mating (pre-mating) or 40 days pre-mating and 17 days post-mating. Liveweight, fat score, plasma fatty acid status and lamb sex was determined. Plasma n-6 concentration was higher (P < 0.001) and the time to oestrus shorter (P < 0.001) when ewes received oats/CSM compared with silage. The proportion of female lambs was higher when ewes were fed a high n-6 compared with low n-6 diet pre-mating only (54.1% vs 44.4%, P = 0.049) and both pre- and post-mating (57.2% vs 43.4%, P = 0.018). The interaction between diet and length of time of feeding was not significant (P = 0.537). The mechanism resulting in the diet high in omega-6 influencing the sex ratio of lambs appears to operate before or around conception but is yet to be determined.

Privation, stress, and human sex ratio at birth

This article reviews the growing interdisciplinary literature on the effect of privation and stress on human sex ratio at birth. Borrowing strength from the potential outcomes causal analysis framework, the discussion focuses on the issues of study design and identification strategy and how they have influenced the current state of the field. The review suggests that much of the inconsistency in the literature regarding the effect of privation and stress on human sex ratio at birth is due to the weak designs and over-simplistic identification strategies used in previous studies. Studies based on natural experimental designs and well-thought-out identification strategies, on the other hand, have produced rather compelling and consistent evidence suggesting that maternal privation and stress during pregnancy reduce male births.

Does the Mother or Father Determine the Offspring Sex Ratio? Investigating the Relationship between Maternal Digit Ratio and Offspring Sex Ratio

OBJECTIVE

In mammals, high parental testosterone levels present around the time of conception are thought to skew offspring sex ratio toward sons. The second to fourth digit ratio (digit ratio) is now widely accepted as a negative correlate of prenatal testosterone. Thus, we investigated the association between digit ratio and offspring sex ratio.

METHODS

A total of 508 Korean patients (257 males and 251 females) less than 60 years old who had one or more offspring were prospectively enrolled. The lengths of the 2nd and 4th digits of the right hand were measured by a single investigator using a digital vernier calliper. Next, the patients' lifetime offspring birth sex ratios were investigated.

RESULTS

Maternal (rather than paternal) digit ratio was significantly associated with the number of sons (r = -0.153, p = 0.015), number of daughters (r = 0.130, p = 0.039), and offspring sex ratio (r = -0.171, p = 0.007). And, the maternal digit ratio was a significant factor for predicting offspring sex ratio (B = -1.620, p = 0.008) on multiple linear regression analysis. The female patients with a lower digit ratio (< 0.95) were found to have a higher offspring sex ratio (0.609 versus 0.521, p = 0.046) compared to those with a higher digit ratio (≥ 0.95). Furthermore, females in the low digit ratio group have a probability 1.138 greater of having sons than females in the high digit ratio group.

CONCLUSIONS

Maternal digit ratio was negatively associated with offspring sex ratio. Females with a lower digit ratio were more likely to have more male offspring compared to those with a higher digit ratio. Thus, our results suggest that the sex of offspring might be more influenced by maternal rather than paternal factors.

Periconceptional Multivitamin Supplementation Containing Folic Acid and Sex Ratio at Birth in a Chinese Population: a Prospective Cohort Study

BACKGROUND

To determine whether periconceptional use of multivitamin supplements containing folic acid increases the occurrence of male births in a Chinese population.

METHODS

A prospective cohort study was carried out in 18 counties in four provinces of China. Participants were naturally and voluntarily divided into an intervention group (who took a multivitamin pill containing folic acid, n = 25,418) and a control group (who did not take any multivitamin, n = 26,580). Multivitamin supplements containing folic acid was ascertained before pregnancy. Pregnant women were followed through the first trimester of pregnancy and the outcome of pregnancy (i.e. livebirth, stillbirth, or fetal death; sex at birth) was recorded.

RESULTS

A total of 52,043 pregnancies and 51,998 births were recorded between September 2000 and August 2002. The proportion of males born to women who did and did not take the multivitamin were 54.8% (n = 13,935) and 54.0% (n = 11,483), respectively. The male to female sex ratios at birth among women who did and did not take the multivitamin were 117:100 and 121:100, respectively. The risk ratio was 1.03 [95% confidence interval 0.99, 1.06] after adjusting for confounding factors.

CONCLUSIONS

These findings suggest that periconceptional multivitamin supplementation containing folic acid is not associated with an increased likelihood of male births in a Chinese population. However, these results may have been affected by induced abortion or selective termination of pregnancy, and the findings must therefore be cautiously interpreted.

Low Gestational Weight Gain Skews Human Sex Ratios towards Females

BACKGROUND

Human males are more vulnerable to adverse conditions than females starting early in gestation and continuing throughout life, and previous studies show that severe food restriction can influence the sex ratios of human births. It remains unclear, however, whether subtle differences in caloric intake during gestation alter survival of fetuses in a sex-specific way. I hypothesized that the ratio of male to female babies born should vary with the amount of weight gained during gestation. I predicted that women who gain low amounts of weight during gestation should produce significantly more females, and that, if gestational weight gain directly influences sex ratios, fetal losses would be more likely to be male when women gain inadequate amounts of weight during pregnancy.

METHODS

I analyzed data collected from over 68 million births over 23 years to test for a relationship between gestational weight gain and natal sex ratios, as well as between gestational weight gain and sex ratios of fetal deaths at five gestational ages.

RESULTS

Gestational weight gain and the proportion of male births were positively correlated; a lower proportion of males was produced by women who gained less weight and this strong pattern was exhibited in four human races. Further, sex ratios of fetal losses at 6 months of gestation were significantly male-biased when mothers had gained low amounts of weight during pregnancy, suggesting that low caloric intake during early fetal development can stimulate the loss of male fetuses.

CONCLUSION

My data indicate that human sex ratios change in response to resource availability via sex-specific fetal loss, and that a pivotal time for influences on male survival is early in fetal development, at 6 months of gestation.

Multi-factorial influences on sex ratio: a spatio-temporal investigation of endocrine disruptor pollution and neighborhood stress

Background:

It is suggested the declining male birth proportion in some industrialized countries is linked to ubiquitous endocrine disruptor exposure. Stress and advanced parental age are determinants which frequently present positive findings. Multi-factorial influences on population sex ratio are rarely explored or tested in research.

Objectives:

To test the hypothesis that dual factors of pollution and population stress affects sex proportion at birth through geographical analysis of Central Scotland.

Methods:

The study incorporates the use of Geographical Information Systems (GIS) tools to overlay modeled point source endocrine disruptor air emissions with “small-area” data on multiple deprivation (a proxy measurement of stress) and birth sex. Historical review of regional sex ratio trends presents additional data on sex ratio in Scotland to consider.

Results:

There was no overall concentration in Central Scotland of low sex ratio neighborhoods with areas where endocrine disruptor air pollution and deprivation or economic stress were high. Historical regional trends in Scotland (from 1973), however, do show significantly lower sex ratio values for populations where industrial air pollution is highest (i.e. Eastern Central Scotland).

Conclusions:

Use of small area data sets and pollution inventories is a potential new method of inquiry for reproductive environmental and health protection monitoring and has produced interesting findings.

Exposure to childhood traumas ups the odds of giving birth to daughters

This study examined the likelihood of giving birth to a daughter as a function of women's exposure to four categories of stressors: childhood trauma, adult trauma, chronic stressors, and recent (adverse) life events. Hypothesis 1 stated that exposure to recent life events (near conception) and to childhood traumas would increase women's chances of having a girl baby. Hypothesis 2 stated that the relationship between stress and gender outcome is mediated by persistent posttraumatic stress disorder (PTSD) symptoms. The final sample was comprised of 225 women. The design was prospective observational. At first contact, women were retained if they were <27 weeks pregnant and met initial inclusion criteria. In interview 2, at 27-30 weeks, women were excluded for positive diagnoses of anxiety disorders besides PTSD with or without depression (Structured Clinical Interview for DSM-IV Disorders). In interview 3 (30-34 weeks), reports on stress categories (Social Stress Indicator Questionnaire) and PTSD symptoms (Post-Traumatic Checklist) were obtained. Infant gender was obtained from medical records. The relationship between stress categories and the distribution of girl/boy infants was examined with Chi Squares and logistic regression analyses. Mediation was tested with the macro PROCESS (Hayes 2012). Childhood trauma was the only stress category that increased the odds of having a girl, with an odds ratio of >3.0 for women who had been exposed to more than two such events. PTSD symptoms (partially) mediated the relationship between childhood trauma and infant gender. Findings suggest that women's exposure to childhood trauma contributes to the determination of the sex ratio at birth and that PTSD symptoms are part of the cause.

Chorionic plate arterial function is altered in maternal obesity

Objectives

To characterise Chorionic Plate Artery (CPA) function in maternal obesity, and investigate whether leptin exposure reproduces the obese CPA phenotype in normal-BMI women.

Study design

CPA responses to the thromboxane-A₂ mimetic U46619 (pre/post leptin incubation), to the nitric oxide donor sodium nitroprusside (SNP) and the occurrence of tone oscillations (pre/post leptin incubation) were assessed in 46 term placentas from women of normal (18.5–24.9) or obese (>30) Body Mass Index (BMI).

Outcome measures

Area Under the dose response Curve (AUC), maximum response (V_max), sensitivity (EC₅₀) to U46619 (pre/post leptin) and SNP; average vessel tone, oscillation amplitude and frequency (pre/post leptin).

Results

U46619 vasoconstriction was similar between BMI categories (p > 0.05), however vasodilatation to SNP was reduced in obesity (AUC p = 0.02, V_maxp = 0.04) compared to normal-BMI women. Leptin incubation altered responses to U46619 in both normal-BMI (EC₅₀ at 100 ng/ml leptin; p < 0.05) and obese women (AUC at 50 ng/ml; p < 0.05) but vasomotion was unaffected (p > 0.05).

Conclusions

Maternal obesity is associated with altered placental vascular function which may adversely affect placental oxygen and nutrient transport, placing the fetus at risk. Leptin incubation altered CPA vascular function but did not reproduce the obese phenotype.

Adolescence: Does good nutrition = good behaviour?

Adolescence is often associated with exploring boundaries, rapid growth, hormones and pimples. A stable feature of this turbulent age is that these young people are highly over-represented in the criminal justice system. Adolescents account for disproportionate proportion of police-recorded crimes, and this seems to be a cross-cultural phenomenon. Furthermore, disaffected young people often have limited routine access to healthy foods and make poor food choices. These people form a large proportion of the prison population and there are concerns that insufficient attention is paid to their health. Hence their diet tends to be poor compared with international standards of dietary adequacy, which typically are set to protect the heart but not for optimal brain function. Thus, it has been posited that a poor diet may be a modifiable causal factor in antisocial behaviours. We tested what happened to the behaviour of violent young adult prisoners (18-21years) when nutrients missing from their diets were reinstated. We used food supplements as an analogue of a better diet because it provided the possibility of a placebo control. On a random basis, where neither the volunteers, prison staff nor researchers in the prison knew who was getting which type, 231 volunteers were given either placebo or real capsules containing broadly the daily requirements of vitamins, minerals and essential fatty acids. The number of proven offences committed by each prisoner was monitored before and while taking supplements. The result was that those who received the extra nutrients committed significantly (26.3%) fewer offences compared with placebos. Those consuming real supplements for at least 2 weeks committed 37% fewer (highly statistically significant) of the most serious offences, such as violence. These findings have been replicated by the Dutch Ministry of Justice; their double-blind study reported a 48% difference between groups. If these studies are widely replicated - and they need to be - we may have a simple and humane means to help reduce and prevent a significant proportion of violence and antisocial behaviour. This should also work in the community, because it is not about where you eat but what you eat. Indeed, criminal justice systems are often over-represented with ethnic minorities, but providing a more nutritious diet is never going to be discriminatory to these young people. The only risk is better health.

Sex differences in developmental programming models

The theory of developmental programming suggests that diseases such as the metabolic syndrome may be ‘programmed’ by exposure to adverse stimuli during early development. The developmental programming literature encompasses the study of a wide range of suboptimal intrauterine environments in a variety of species and correlates these with diverse phenotypic outcomes in the offspring. At a molecular level, a large number of variables have been measured and suggested as the basis of the programmed phenotype. The range of both dependent and independent variables studied often makes the developmental programming literature complex to interpret and the drawing of definitive conclusions difficult. A common, though under-explored, theme of many developmental programming models is a sex difference in offspring outcomes. This holds true across a range of interventions, including dietary, hypoxic, and surgical models. The molecular and phenotypic outcomes of adversein uteroconditions are often more prominent in male than female offspring, although there is little consideration given to the basis for this observation in most studies. We review the evidence that maternal energy investment in male and female conceptuses may not be equal and may be environment dependent. It is suggested that male and female development could be viewed as separate processes from the time of conception, with differences in both timing and outcomes.