Maternal eating disorders influence sex ratio at birth

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.

Disease exposure in infancy affects women's reproductive outcomes and offspring health in southern Sweden 1905-2000

Ample evidence demonstrates that early-life adversity negatively affects morbidity and survival in late life. We show that disease exposure in infancy also has a continuous impact on reproduction and health across the female life course and even affects early-life health of the next generation. Using Swedish administrative data, obstetric records, and local infant mortality rates as a measure of disease exposure, we follow women's reproductive careers and offspring health 1905-2000, examining a comprehensive set of outcomes. Women exposed to disease in infancy give birth to a lower proportion of boys, consistent with notions that male fetuses are more vulnerable to adverse conditions and are more often miscarried. Sons of exposed mothers are also more likely to be born preterm and have higher birthweight suggesting in utero out-selection. Exposed women have a greater risk of miscarriage and of male stillbirth, but their overall likelihood of giving birth is not affected.

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.

Role of omega-6 and omega-3 fatty acids in fetal programming

Maternal nutrition plays a critical role in fetal development and can influence adult onset of disease. Linoleic acid (LA) and alpha-linolenic acid (ALA) are major omega-6 (n-6) and n-3 polyunsaturated fatty acids (PUFA), respectively, that are essential in our diet. LA and ALA are critical for the development of the fetal neurological and immune systems. However, in recent years, the consumption of n-6 PUFA has increased gradually worldwide, and elevated n-6 PUFA consumption may be harmful to human health. Consumption of diets with high levels of n-6 PUFA before or during pregnancy may have detrimental effects on fetal development and may influence overall health of offspring in adulthood. This review discusses the role of n-6 PUFA in fetal programming, the importance of a balance between n-6 and n-3 PUFAs in the maternal diet, and the need of further animal models and human studies that critically evaluate both n-6 and n-3 PUFA contents in diets.

Dysfunctional eating behaviour, psychological well-being and adaptation to pregnancy: A study with women in the third trimester of pregnancy

This study evaluated the prevalence and predictors of dysfunctional eating. Women in the third trimester of pregnancy participated in this study ( N = 105). Dysfunctional eating was associated with a higher body mass index, enhanced negative body image, more somatic symptoms, poorer marital relationships, more negative attitudes regarding pregnancy and the baby and more emotional problems. A higher body mass index prior to the pregnancy, higher weight gain during pregnancy and a more negative perception of body image predicted dysfunctional eating. Clinicians must be aware of the presence of dysfunctional eating during pregnancy to prevent relevant physiological and psychosocial consequences during this stage.

Eating Disorders, Pregnancy, and the Postpartum Period: Findings from the Norwegian Mother and Child Cohort Study (MoBa)

This review summarizes studies on eating disorders in pregnancy and the postpartum period that have been conducted as part of the broader Norwegian Mother and Child Cohort Study (MoBa). Prior to the 2000s, empirical literature on eating disorders in pregnancy was sparse and consisted mostly of studies in small clinical samples. MoBa has contributed to a new era of research by making population-based and large-sample research possible. To date, MoBa has led to 19 studies on diverse questions including the prevalence, course, and risk correlates of eating disorders during pregnancy and the postpartum. The associations between eating disorder exposure and pregnancy, birth and obstetric outcomes, and maternal and offspring health and well-being, have also been areas of focus. The findings indicate that eating disorders in pregnancy are relatively common and appear to confer health risks to mother and her child related to sleep, birth outcomes, maternal nutrition, and child feeding and eating.

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.

Reproductive issues in anorexia nervosa

Despite a high prevalence of menstrual irregularities, women with anorexia nervosa are becoming pregnant. The physical and psychological demands of pregnancy and motherhood can represent an immense challenge for women already struggling with the medical and psychological stress of an eating disorder. This article summarizes key issues related to reproduction in women with anorexia nervosa, highlighting the importance of preconception counseling, adequate gestational weight gain, and sufficient pre- and post-natal nutrition. Postpartum issues including eating disorder symptom relapse, weight loss, breastfeeding, and risk of perinatal depression and anxiety are also discussed.

Geographic clustering of the secondary sex ratio in Japan: association with demographic attributes

The secondary sex ratio (SSR) has been suggested to decrease with adverse physical and psychological environments. Previous studies have focused on reduced SSR under adverse conditions, such as war, terrorism attack and earthquake, but few studies have investigated fluctuations in SSR in moderately adverse environments. This study analysed municipality-level vital statistics records in Japan collected between 1998 and 2002 to identify high-SSR clusters and low-SSR clusters with spatial-scan statistics. In 999 runs of simulation, high- and low-SSR clusters were detected but fewer than 950 times, indicating that SSR was not geographically clustered in Japan if type I error of 5% was adopted. Explorative analyses comparing demographic attributes between high-SSR clusters and low-SSR clusters that were detected more than 500 times in 999 runs of simulation, showed that rate of spontaneous abortion, rate of artificial abortion and divorce rate were higher in low-SSR clusters, while male life expectancy, female life expectancy and total fertility rate were higher in a high-SSR cluster.

Impact of earthquakes on sex ratio at birth: Eastern Marmara earthquakes

OBJECTIVE

Previous reports suggest that maternal exposure to acute stress related to earthquakes affects the sex ratio at birth. Our aim was to examine the change in sex ratio at birth after Eastern Marmara earthquake disasters.

MATERIAL AND METHODS

This study was performed using the official birth statistics from January 1997 to December 2002 - before and after 17 August 1999, the date of the Golcuk Earthquake - supplied from the Turkey Statistics Institute. The secondary sex ratio was expressed as the male proportion at birth, and the ratio of both affected and unaffected areas were calculated and compared on a monthly basis using data from gender with using the Chi-square test.

RESULTS

We observed significant decreases in the secondary sex ratio in the 4th and 8th months following an earthquake in the affected region compared to the unaffected region (p= 0.001 and p= 0.024). In the earthquake region, the decrease observed in the secondary sex ratio during the 8th month after an earthquake was specific to the period after the earthquake.

CONCLUSION

Our study indicated a significant reduction in the secondary sex ratio after an earthquake. With these findings, events that cause sudden intense stress such as earthquakes can have an effect on the sex ratio at birth.

Gestational diabetes mellitus: a positive predictor of type 2 diabetes?

The aim of this paper is to consider the relative benefits of screening for type two diabetes mellitus in women with a previous pregnancy complicated by gestational diabetes mellitus. Recent studies suggest that women who experience GDM are at a greater risk of developing type 2 diabetes within 10-20 years of their index pregnancy. If considered as a stand-alone indicator of the risk of developing type 2 diabetes, GDM is a poor diagnostic test. Most women do not develop GDM during pregnancy and of those that do most do not develop type 2 diabetes. There is, however, a clear need for better early detection of predisposition to disease and/or disease onset to significantly impact on this global pandemic. The putative benefits of multivariate approaches and first trimester and preconception screening to increase the sensitivity of risk assignment modalities for type 2 diabetes are proposed.

Periconceptional influences on offspring sex ratio and placental responses

Maternal diet and secondary factors can strikingly influence fetal outcomes, including biasing offspring sex ratio and altering the molecular biological responses of the conceptus, namely within the placenta. Alterations in the in utero environment might also lead to profound developmental origin of health and disease (DOHaD) outcomes into adulthood, including increased risk for cardiovascular disease, obesity and cancer, with males in general being at greater risk for these diseases. Female mice maintained on a very high fat (VHF) diet birth more sons than those on a chow-based and low fat (LF), high carbohydrate diet, with the latter group producing more daughters. However, neither the underlying mechanisms that contribute to this shift in offspring sex ratio nor when they occur during pregnancy have been resolved. In this review, we consider the evidence that maternal diet and other factors influence secondary sex ratio in a variety of species, including humans, and discuss when this skewing might occur. Additionally, we examine how fetal sex and maternal diet influences gene expression patterns in the mouse placenta, which serves as the primary nutrient acquisition and communication organ between the mother and her developing pups. These adaptations to diet observed as changes in gene expression are likely to provide insight into how the placenta buffers the fetus proper from environmental shifts in nutrient availability during pregnancy and whether male and female conceptuses respond differently to such challenges.

Dietary supplement use immediately before and during pregnancy in Norwegian women with eating disorders

OBJECTIVE

Many pregnant women use dietary supplements. Little is known about dietary supplement use during pregnancy in women with eating disorders.

METHOD

We examined dietary supplement use in 37,307 pregnant women, from the Norwegian Mother and Child Cohort Study.

RESULTS

Dietary supplement use during pregnancy was as follows: 91.2% of women with anorexia nervosa, 92.2% of women with bulimia nervosa, 93.2% of women with eating disorder not otherwise specified-purging subtype (EDNOS-P), 90.6% of women with binge eating disorder, and 93.5% of the women without eating disorders. Between group differences were not statistically significant. After adjusting for covariates, women with EDNOS-P were more likely to take iron containing supplements (p ≤ .04).

DISCUSSION

Overall dietary supplement use in this sample is similar in women with and without eating disorders.

THE CATEGORIES OF EVIDENCE RELATING TO THE HYPOTHESIS THAT MAMMALIAN SEX RATIOS AT BIRTH ARE CAUSALLY RELATED TO THE HORMONE CONCENTRATIONS OF BOTH PARENTS AROUND THE TIME OF CONCEPTION

This note categorizes the evidence for the hypothesis that mammalian offspring sex ratios (proportions male) are causally related to the hormone levels of both parents around the time of conception. Most of the evidence may be acknowledged to be correlational and observational. As such it might be suspected of having been selected; or of having been subject to other forms of bias or confounding; or, at any rate, of being inadequate as a firm basis for causal inference. However, there are other types of evidence that are not vulnerable to these types of criticism. These are from the following sources: (1) previously neglected data from Nazi Germany and Soviet Russia; (2) fulfilled predictions; (3) genetics; and (4) a network of logically (mathematically) related propositions, for some of which there is overwhelming empirical evidence. It is suggested that this variety of evidence confers greater overall credibility on the hypothesis than would be the case if all the evidence were of the same observational/correlational status. This observational/correlational evidence is tabulated to illustrate its consistency.

Behavioural and biological determinants of human sex ratio at birth

The human sex ratio SR (proportion male) at birth has been reported to vary with many variables. The explanation of this variation is not established, but I have hypothesized that it is partially caused by the hormonal concentrations of both parents around the time of conception. The present note suggests how this hypothesis might accommodate recent sex ratio findings relating to 'psychosexual restriction', female genital cutting, sexes of prior sibs, finger length ratios, the autism spectrum disorder, parental occupation and maternal eating disorders. Tests of such suggestions are offered, and it is hypothesized that: (a) in women, Manning's R (the ratio of the lengths of the 2nd and 4th digits) is positively correlated with offspring sex ratio (proportion male); (b) women who have undergone female genital cutting (FGC) have high androgen levels; (c) offspring sex ratio correlates positively with 'masculinity' of parental occupation, the correlation being mediated by testosterone levels. It is noted that the lines of evidence for three hypotheses (James', Manning's and Baron-Cohen's) are mutually supportive.

Childbirth and mental disorders

This review approaches the topic of childbirth and mental illness using a model of perinatal health which takes into consideration the multiple determinants of health, approached from a lifespan perspective. The paper seeks to answer four broad questions using this model and available literature: (1) What is the relationship between childbirth and mental disorders? (2) How common are mental disorders during childbearing, and what is the perinatal course of illness? (3) What are the effects of mental illness during childbearing on foetal and infant developmental outcomes? (4) How do you approach the detection and treatment of mental disorders during the perinatal period?