Associations between nausea and vomiting in pregnancy, disgust sensitivity, and first-trimester maternal serum free ß-hCG and PAPP-A.

Elevated levels of nausea and vomiting in pregnancy (NVP) and disgust sensitivity have been observed in the first trimester and both are thought to have a protective function for the mother and her fetus. Their aetiology is not clear, however, with previous studies attributing elevated NVP and disgust to various factors including endocrine changes, immunological changes, and psychological variables. To date, no study has directly assessed the relationship between disgust and NVP. Here, we prospectively collected two independent samples (S1 and S2; n1 = 201, n2 = 391) of women in the first trimester of pregnancy, who completed the Index of Nausea, Vomiting, and Retching and the Disgust Scale-Revised. We also measured free ß-human chorionic gonadotropin (hCG) and pregnancy-associated plasma protein A (PAPP-A) in maternal serum. Our results did not confirm any association between NVP and disgust; in addition, they indicate that NVP and disgust may have different proximate causes. Disgust sensitivity was significantly negatively correlated with free ß-hCG and (only in S1) with PAPP-A. In contrast, NVP was significantly positively associated with free ß-hCG levels and (only in S1) with PAPP-A. While low hCG levels seem to be an important indicator for activation of the behavioral immune system in the first trimester, increased hCG levels play a role in stronger symptoms of NVP, a result consistent with previous studies. Levels of PAPP-A are likely part of a larger network of immunological and endocrine responses and do not appear to provide sufficient information for predicting women's NVP and disgust sensitivity.

Parental Interference in Offspring's Mate Choice: Sets of Actions and Counteractions Based on Both Perspectives.

Mate choice in humans is specific by the involvement of kin both in partner choice and in the functioning of the relationship. The influence of relatives ranges from providing advice all the way to arranged marriages. Existing research so far tended to map neither the actual parental interventions and further reactions (counteractions) nor the independently pursued behavior (actions) by which the offspring or their partners assert their interests. This study identified such sets of behaviors through semi-structured individual interviews with members of 20 dyads of adult offspring and their biological parents (five son-mother, five son-father, five daughter-mother, and five daughter-father dyads). Thematic analysis revealed sets of parental actions aimed at the offspring, their partners, and the couple as a whole, as well as further counteractions (reactions to parental interference) and independently pursued behavior (actions) of the offspring and their partners aimed at the parents in the context of the offspring's previous or current relationship. Our findings showed that parental interference differed depending on the recipient: toward the couple were applied mainly indirect and supportive parental actions, whereas when facing their offspring or offspring's partner, parents' actions were more direct and disruptive. Our results thus indicate the importance of reporting about actual interactions which differ from the hypothetical settings used in prior studies by lower intensity. Moreover, by interviewing both members of dyads, we expanded the sets of actions and counteractions identified by prior studies and managed to limit self-reporting bias.

Testing effects of partner support and use of oral contraception during relationship formation on severity of nausea and vomiting in pregnancy.

BACKGROUND: A recent study focusing on dietary predictors of nausea and vomiting in pregnancy (NVP) found that women with higher levels of partner support, and those who had used oral contraception (OC) when they met the father, both tended to report less severe NVP compared with previous non-users or those with less supportive partners. We provide a further test of these factors, using a large sample of women from four countries who retrospectively scored their NVP experience during their first pregnancy. METHODS: We recruited women who had at least one child to participate in a retrospective online survey. In total 2321 women completed our questionnaire including items on demographics, hormonal contraception, NVP, and partner support. We used general linear models and path analysis to analyse our data. RESULTS: Women who had used OC when they met the father of their first child tended to report lower levels of NVP, but the effect size was small and did not survive adding the participant's country to the model. There was no relationship between NVP and partner support in couples who were still together, but there was a significant effect among those couples that had since separated: women whose ex-partner had been relatively supportive reported less severe NVP. Additional analyses showed that women who were older during their first pregnancy reported less severe NVP, and there were also robust differences between countries. CONCLUSIONS: These results provide further evidence for multiple influences on women's experience of NVP symptoms, including levels of perceived partner support.

Cowards or clever guys: an alternative nest defence strategy employed by shrikes against magpies.

Red-backed shrikes (Lanius collurio) show a substantial variability in their nest defence behaviour, which usually follows the rules of optimal parental behaviour, vigorously attacking egg and chick predators and only passively guarding against harmless animals. Nevertheless, shrikes hesitate to attack the Eurasian magpie (Pica pica), which specializes in plundering passerine nests. Our previous studies have suggested that this behaviour may be the result of an alternative defence strategy, relying on nest crypsis. To test this hypothesis, at the shrike nests, we presented a magpie dummy associated with playbacks drawing the predators' attention to the presence of the nest. We predicted that the presentation of a magpie dummy associated with shrike alarm calls moves the parents to action, causing them to chase the magpie away from the nest. We showed that the presence of a magpie dummy associated with shrike alarm calls elicits a significantly more active response in shrike parents compared to a magpie dummy associated with neutral song. Parents actively moved around the dummy and produced alarm calls; nevertheless, most of the tested pairs hesitated to attack the dummy. We may conclude that the low nest defence activity of shrike parents towards magpie dummy was partly the result of an alternative strategy, which may be cancelled out by alerting the predator to the location of the nest; nevertheless, shrikes seem to be afraid of the magpie and hesitate to attack it physically.

Marriage does not relate to major histocompatibility complex: a genetic analysis based on 3691 couples.

Optimization of chances for healthy offspring is thought to be one of the factors driving mate choice and compatibility of the major histocompatibility complex (MHC) is assumed to determine the offspring's fitness. While humans have been claimed to be able to perceive information of MHC compatibility via the olfactory channel, it remains unknown whether humans use such information for mate choice. By investigation of 3691 married couples, we observed that the high polymorphism of MHC leads to a low chance for homozygous offspring. MHC similarity between couples did not differ from chance, we hence observed no MHC effect in married couples. Hormonal contraception at the time of relationship initiation had no significant effect towards enhanced similarity. A low variety of alleles within a postcode area led to a higher likelihood of homozygous offspring. Based on this data, we conclude that there is no pattern of MHC dis-assortative mating in a genetically diverse Western society. We discuss the question of olfactory mate preference, in-group mating bias and the high polymorphism as potential explanations.

More Than Smell-COVID-19 Is Associated With Severe Impairment of Smell, Taste, and Chemesthesis.

Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments, such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation, and initial results of a multilingual, international questionnaire to assess self-reported quantity and quality of perception in 3 distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, and 8 others, aged 19-79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste, and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change ±100) revealed a mean reduction of smell (-79.7 ± 28.7, mean ± standard deviation), taste (-69.0 ± 32.6), and chemesthetic (-37.3 ± 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell but also affects taste and chemesthesis. The multimodal impact of COVID-19 and the lack of perceived nasal obstruction suggest that severe acute respiratory syndrome coronavirus strain 2 (SARS-CoV-2) infection may disrupt sensory-neural mechanisms.

The effects of intrapartum synthetic oxytocin on maternal postpartum mood: findings from a prospective observational study.

Postpartum depression (PPD) affects up to 19% of all mothers, with detrimental effects on both mother and child. The antidepressant and anxiolytic effects of plasma oxytocin are well-documented, but it is still disputable whether synthetic oxytocin (synOT) may protect women against postpartum mood alterations. The current study examined the association between synOT intrapartum and maternal mood postpartum using a prospective design. Two hundred sixty women were screened for depressive symptoms in the last trimester of pregnancy and then again 6 weeks and 9 months postpartum using the Edinburgh Postnatal Depression Scale. They also completed Maternity Blues Questionnaire in the first postpartum week. The data concerning the intrapartum interventions and health status of the newborn were extracted from the medical records. Cox proportional hazards regression adjusted for a history of depression, mode of delivery, and childbirth experience showed that synOT predicted a significantly lower risk of PPD (HR = 0.65, 95% CI 0.45-0.95, p = 0.025). The risk factors for PPD included a history of depression (HR = 3.20, 95% CI 2.33-4.40, p < 0.001) and negative childbirth experience (HR = 1.39, 95% CI 1.01-1.90, p = 0.040). Logistic regression adjusted for the same covariates found no significant effect of synOT on maternity blues (OR = 0.64, 95% CI 0.31-1.32, p = 0.23). While synOT administered intrapartum does not affect maternal mood immediately, it may come to effect some weeks after childbirth to protect mothers from developing PPD symptoms.

Age and Pubertal Status-Related Changes in Reports of Perception of Personal Odors.

As previously suggested, preferences for kin body odor might undergo an adaptive change over the course of puberty in order to avoid potential inbreeding, resulting in aversion to body odor of the opposite-gender kin as individuals mature sexually. However, studies based on mutual body odor aversion are rather inconclusive. We therefore investigated whether children's reports of individuals smelling good or bad differed as a function of age and pubertal status. We asked 219 children (94 male) aged 10 to 15 years to assess their pubertal development using a standardized measure and to name individuals they thought smelled good or bad. Results of the present study show that the older the girls were, the more likely they were to name males than females among nice-smelling people. Further, in both girls and boys alike, children with higher puberty scores were more likely to name children than adults. Neither in girls nor in boys did we observe any concurrent effect of age or pubertal status on children's reports of persons thought to smell bad. Irrespective of whether these changes are driven by age itself or age-related phenomena, these results suggest a shift toward a more general positive attitude to peers rather than active kin avoidance.

Effect of Biological Relatedness on Perfume Selection for Others: Preliminary Evidence.

People tend to choose perfumes to complement their body odour. As kin share some body odour qualities, their ability to select complementary perfumes for relatives might be higher compared with selection for nonrelatives. We tested this in two studies, comparing selection of a perfume for a target man by himself and by either a familiar but unrelated individual (girlfriend; Study 1) or a relative (sister; Study 2). Target men applied the two perfumes (own or other's choice) to their axillae and then wore cotton pads for 12 hr. Collected perfume-body odour blends and perfumes alone were assessed by rater panels. In Study 1, the blends were rated as nominally more pleasant when body odours were mixed with the perfumes selected by girlfriends compared with those selected by target men themselves. In Study 2, body odours mixed with perfumes selected by sisters were rated significantly more attractive than those mixed with perfumes selected by target men. No significant differences were found for attractiveness and pleasantness ratings when perfumes were rated alone, suggesting that it was the resulting blends that were uniquely different. Our results indicate that sisters might be particularly tuned to select suitable perfumes for their siblings.

Hormonal Contraceptive Use During Relationship Formation and Sexual Desire During Pregnancy.

Women who are regularly cycling exhibit different partner preferences than those who use hormonal contraception. Preliminary evidence appears to suggest that during pregnancy women's partner preferences also diverge from those prevalent while regularly cycling. This is consistent with the general assertion that women's mate preferences are impacted by hormonal variation. During pregnancy, women's preferences are thought to closely resemble those displayed by women who are using hormonal contraception. Here, based on this literature, we compared levels of sexual desire among pregnant women who met their partner while using hormonal contraception and pregnant women who met their partner while regularly cycling. We predicted that women who met their partner while using hormonal contraception would experience higher levels of in-pair sexual desire during pregnancy since these women will have partner preferences that more closely match those prevalent at the time of their partner choice. Our results provided support for the idea that previous contraceptive use/non-use may impact subsequent sexual desire for the partner during pregnancy. Pregnant women who met their partner while using hormonal contraception (N = 37) were shown to have higher levels of in-pair sexual desire than those who met while regularly cycling (N = 47). In contrast, levels of extra-pair desire were not related to previous use/non-use of hormonal contraception. These findings were robust when controlling for a number of relevant individual difference variables known to impact sexual desire. Our results contribute to our understanding of factors affecting relationship functioning during pregnancy.

Consumption of garlic positively affects hedonic perception of axillary body odour.

Beneficial health properties of garlic, as well as its most common adverse effect - distinctive breath odour - are well-known. In contrast, analogous research on the effect of garlic on axillary odour is currently missing. Here, in three studies varying in the amount and nature of garlic provided (raw garlic in study 1 and 2, garlic capsules in study 3), we tested the effect of garlic consumption on the quality of axillary odour. A balanced within-subject experimental design was used. In total, 42 male odour donors were allocated to either a "garlic" or "non-garlic" condition, after which they wore axillary pads for 12 h to collect body odour. One week later, the conditions were reversed. Odour samples were then judged for their pleasantness, attractiveness, masculinity and intensity by 82 women. We found no significant differences in ratings of any characteristics in study 1. However, the odour of donors after an increased garlic dosage was assessed as significantly more pleasant, attractive and less intense (study 2), and more attractive and less intense in study 3. Our results indicate that garlic consumption may have positive effects on perceived body odour hedonicity, perhaps due to its health effects (e.g., antioxidant properties, antimicrobial activity).

Further evidence for links between facial width-to-height ratio and fighting success: Commentary on Zilioli et al. (2014).

Recent research has reported an association between facial width-to-height ratio (fWHR) and both fighting performance and judgments of formidability in a sample of mixed martial arts (MMA) combatants. The results provide evidence of fWHR being associated with sporting performance and aggression in men. However, it has been argued that the effect of fWHR might be a by-product of associations between body size and behavioral measures. Here we tested whether fWHR is associated with perceived aggressiveness, fighting ability and success in physical confrontation, while controlling for body size, also in a sample of MMA fighters. We found that perceived fighting ability was predicted by weight but not by fWHR. In contrast, both fWHR and body weight independently predicted perceived aggressiveness. Furthermore, we found positive associations between fWHR and fighting performance which appear to be independent of body size. Our findings provide further support for the proposal that fWHR is associated with fighting ability and perceived aggression, and that these effects are independent of body size. Therefore, fWHR might be considered as a viable and reliable marker for inference of success in male intra-sexual competition.

Partner choice, relationship satisfaction, and oral contraception: the congruency hypothesis.

Hormonal fluctuation across the menstrual cycle explains temporal variation in women's judgment of the attractiveness of members of the opposite sex. Use of hormonal contraceptives could therefore influence both initial partner choice and, if contraceptive use subsequently changes, intrapair dynamics. Associations between hormonal contraceptive use and relationship satisfaction may thus be best understood by considering whether current use is congruent with use when relationships formed, rather than by considering current use alone. In the study reported here, we tested this congruency hypothesis in a survey of 365 couples. Controlling for potential confounds (including relationship duration, age, parenthood, and income), we found that congruency in current and previous hormonal contraceptive use, but not current use alone, predicted women's sexual satisfaction with their partners. Congruency was not associated with women's nonsexual satisfaction or with the satisfaction of their male partners. Our results provide empirical support for the congruency hypothesis and suggest that women's sexual satisfaction is influenced by changes in partner preference associated with change in hormonal contraceptive use.

Shape differences between the faces of homosexual and heterosexual men.

Previous studies have shown that homosexual men differ from heterosexual men in several somatic traits and lay people accurately attribute sexual orientation based on facial images. Thus, we may predict that morphological differences between faces of homosexual and heterosexual individuals can cue to sexual orientation. The main aim of this study was to test for possible differences in facial shape between heterosexual and homosexual men. Further, we tested whether self-reported sexual orientation correlated with sexual orientation and masculinity-femininity attributed from facial images by independent raters. In Study 1, we used geometric morphometrics to test for differences in facial shape between homosexual and heterosexual men. The analysis revealed significant shape differences in faces of heterosexual and homosexual men. Homosexual men showed relatively wider and shorter faces, smaller and shorter noses, and rather massive and more rounded jaws, resulting in a mosaic of both feminine and masculine features. In Study 2, we tested the accuracy of sexual orientation judgment from standardized facial photos which were assessed by 80 independent raters. Binary logistic regression showed no effect of attributed sexual orientation on self-reported sexual orientation. However, homosexual men were rated as more masculine than heterosexual men, which may explain the misjudgment of sexual orientation. Thus, our results showed that differences in facial morphology of homosexual and heterosexual men do not simply mirror variation in femininity, and the stereotypic association of feminine looking men as homosexual may confound judgments of sexual orientation.

The fallacy of global comparisons based on per capita measures.

Media, social scientists and public health researchers often present comparisons across countries, and policy makers use such comparisons to take evidence-based action. For a meaningful comparison among countries, one often needs to normalize the measure for differences in population size. To address this issue, the first choice is usually to calculate per capita ratios. Such ratios, however, normalize the measure for differences in population size directly only under the highly restrictive assumption of a proportional increase of the measure with population size. Violation of this assumption frequently leads to misleading conclusions. We compare per capita ratios with an approach based on regression, a widely used statistical procedure that eliminates many of the problems with ratios and allows for straightforward data interpretation. It turns out that the per capita measures in three global datasets (gross domestic product, COVID-19-related mortality and CO2 production) systematically overestimate values in countries with small populations, while countries with large populations tend to have misleadingly low per capita ratios owing to the large denominators. Unfortunately, despite their biases, comparisons based on per capita ratios are still ubiquitous, and they are used for influential recommendations by various global institutions. Their continued use can cause significant damage when employed as evidence for policy actions and should therefore be replaced by a more scientifically substantiated and informative method, such as a regression-based approach.

Olfactory self-inspection: Own body odour provides cues to one's health and hygiene status.

Olfactory self-inspection has been observed in various mammals, including humans. This behaviour can help individuals to monitor own state, including health and hygiene. This study's aim was to explore the frequency of sniffing particular body parts and investigate possible gender differences. Further, we tested a possible function of this behaviour, namely monitoring health and hygiene, by investigating associations between the frequency of self-sniffing and health, hygiene, and disgust sensitivity. Respondents completed an online survey on self-sniffing behaviour, health status, hygiene habits, and disgust sensitivity. Self-sniffing behaviour was investigated using a purpose-built inventory which explored the incidence and frequency of sniffing different parts of own body. Principal Component Analysis identified three main axes of self-sniffing behaviour: Social acceptability self-inspection, Intimate self-inspection, and Cosmetic self-inspection. Our results further show that respondents with lower standards of hygienic habits engage significantly more in intimate self-inspection (sniffing body parts such as genitals, anus, or navel). Interestingly, individuals who reported more frequent health issues sniff more frequently areas such as the armpits, feet, or own breath (Social acceptability self-inspection), probably to check for possible changes in smell due to illness. Our results indicate that olfactory self-inspection probably has several functions depending on the location from which the smell originates.

Children's odor pleasantness ratings may not differ according to pubertal status: Preliminary results from a sample of 11-14-year-old Czech children.

Puberty tends to be viewed as a "turning point" in hedonic perception of body odor (BO)-related smells. The pubertal stage, a potential proxy for the underlying physiological changes, may contribute to variation in odor hedonic perception. Other potential modulators of odor hedonics are general semantic knowledge about odors (which also tends to be subsumed under the term "age") and perceived odor intensity. The present cross-sectional study examined differences in hedonic odor perception across puberty in 205 Czech children aged 11-14 (89 boys). We investigated whether children differ in the hedonic appraisal of BO-related (16-androstenes and castoreum control), but also food and non-food odors according to their pubertal (penis/breast and pubic hair) development and general semantic knowledge about odors (operationalized as odor identification), controlling for age and perceived odor intensity. As a subsidiary aim, we examined variation in odor identification. We asked the children to self-stage themselves using drawings depicting Tanner's penis/breast and pubic hair stages of pubertal development, estimated their general semantic knowledge about odors with a Sniffin' Sticks identification test, and obtained their pleasantness and intensity ratings of body odor-related, food, a non-food smells. We found that the participants' ratings of the 16-androstenes and those of the perceptually similar odor of castoreum differed according to perceived intensity and, in the latter case, in boys vs. girls as well, but there were no influences of pubertal status or odor identification on the perceived pleasantness. Similarly, hedonic appraisal of non-food (but not food) odors was only influenced by perceived intensity. Regarding odor identification, differences between boys and girls were limited to younger children and did not become more marked throughout puberty. Perceived pleasantness of odors, irrespective of whether they are associated with body smells, food, or other, does not appear to vary across puberty, and boys and girls seem to achieve similar levels of semantic odor knowledge as they grow up.

Small effects of olfactory identification and discrimination on global cognitive and executive performance over 1 year in aging people without a history of age-related cognitive impairment.

Olfactory and cognitive performance share neural correlates profoundly affected by physiological aging. However, whether odor identification and discrimination scores predict global cognitive status and executive function in healthy older people with intact cognition is unclear. Therefore, in the present study, we set out to elucidate these links in a convenience sample of 204 independently living, cognitively intact healthy Czech adults aged 77.4 ± 8.7 (61-97 years) over two waves of data collection (one-year interval). We used the Czech versions of the Montreal Cognitive Assessment (MoCA) to evaluate global cognition, and the Prague Stroop Test (PST), Trail Making Test (TMT), and several verbal fluency (VF) tests to assess executive function. As a subsidiary aim, we aimed to examine the contribution of olfactory performance towards achieving a MoCA score above vs. below the published cut-off value. We found that the MoCA scores exhibited moderate associations with both odor identification and discrimination. Furthermore, odor identification significantly predicted PST C and C/D scores. Odor discrimination significantly predicted PST C/D, TMT B/A, and standardized composite VF scores. Our findings demonstrate that olfaction, on the one hand, and global cognition and executive function, on the other, are related even in healthy older people.