Beyza Ustun-Elayan

Prenatal flavor exposure is known to provide the foundation for later flavor or odor preferences in humans, yet the persistence of fetal flavor/odor memories into early childhood remains unclear. In previous studies, fetuses at 32‐ and 36 weeks gestation were shown to display discriminative facial reactions following a single‐dose flavor stimulation (bitter kale vs. non‐bitter carrot), and repeated exposure to these flavors from 36 weeks until birth was associated with responses to flavor‐specific odors in the first postnatal month. The current longitudinal follow‐up tested whether the prenatal exposure to two specific flavors results in flavor‐specific odor reactions at 3 years of age. Children ( n = 12) who had participated in the fetal and neonatal phases of the study were tested at 3 years of age using controlled olfactory presentations of the same flavors. Results showed that the 3‐year‐olds exhibited a significantly reduced rate of negative facial expressions in response to the odor they had been repeatedly exposed to in utero ( p < 0.001), indicating continuity from prenatal sensory experience to early childhood behavioral responses. Thus, flavor exposure in late gestation can result in long‐lasting flavor/odor memory, confirming that the prenatal chemosensory environment can shape behavioral tendencies years after birth.

While advances in behavioural and neuroimaging methods suitable for use with infants have greatly increased our understanding of infant brain function, cognition and behaviour in recent years, relatively little is known about the rapid period of development during the last trimester of pregnancy and first weeks and months after birth, as well as the roles that the social environment and stress play in shaping this development. This protocol paper outlines The UK Perinatal Imaging in Partnership with Families (PIPKIN) Study, a unique, multi-method, longitudinal cohort study investigating the early development of fetal and infant neurocognitive function and behaviour, and how the infant’s social and family environment shapes this development. The study follows families from a range of socio-economic backgrounds who participate at ten timepoints, from the third trimester of pregnancy until their infant is nine months old, with three visits taking place during the infant’s first postnatal month. The study harnesses recent methodological advances coupled with the drive for more ecologically valid data collection by undertaking many of these visits in families’ homes. Methods include measures of fetal behaviour using 4D ultrasound scanning; infant brain imaging using fNIRS and EEG; a full-day video recording of the home environment from the infant’s perspective, with physiological measures; measures of recent stress in both infant and mother; questionnaires relating to the home environment as well as parents’ feelings, attitudes, health and parenting routines; and standardised measures of infant behaviour and development. Specific aims are to investigate: i) individual differences in basic sensory, behavioural and motor processing between late prenatal and early postnatal periods; ii) rapid change in cortical functions over the first month, particularly for brain networks that support social behaviour; iii) effects of social interaction on developing brain function; and iv) individual differences in developmental trajectories associated with poverty-related contextual factors.

Offering financial incentives to participants for their participation in qualitative research is a common practice that improves recruitment in a study. However, the state of incentive use in qualitative research across fields is unknown. This methodological review aimed to examine the state of incentive use in qualitative research across fields in the context of the United States. Using descriptive statistics and negative binomial regression, we examined 698 cases of incentives for 627 unique full-text empirical qualitative research articles and determined the influencing factors for the amounts of incentives used in qualitative research studies. The results showed that publication year, field of research, and sample size function as influencing factors in the amount of incentives offered in qualitative studies. Of the 698 cases identified through the systematic search, incentive amounts (US Dollar) varied from minimum $5.00 to maximum $500.00 with mean of $31.7 (SD=32.1). The incentive amounts (US Dollar) with the inflation rate varied from $5.00 to maximum $565.00 with a mean of $36.6 (SD=37.4). Our study suggests that incentives in qualitative research are shaped by disciplinary and methodological contexts, and our review provides practical implications to guide researchers’ decisions. This study ignites a deeper dialogue about the use of incentives in qualitative research and reporting practices to assist researchers in enhancing the effectiveness of using incentives within their respective fields.

Background: Returning to work following maternity leave represents a critical transition in the postpartum period, often occurring while mothers are still navigating disrupted sleep, breastfeeding demands, and hormonal changes. Workplace conditions can either safeguard or intensify these challenges, with implications for maternal mental health and wellbeing. Aim: To explore the psychosocial experiences of mothers returning to work following maternity leave, focusing on the experience with workplace support and sleep deprivation. Methods: A qualitative descriptive study was conducted using an open-ended online survey. Twenty-five mothers in the UK with an infant under two years of age who had recently returned to work or were return following maternity leave. Participants were recruited via mother-and-baby groups, social media, and personal networks using purposive sampling. Reflexive thematic analysis was used, with analytical attention to maternal mental health, workplace structures, and sleep-related challenges. Findings: Five interrelated themes were developed as follows: Making Ends Meet, Losing Myself; The Bittersweet Return; Workplaces That Work (or Don’t); Running on Empty; and This Isn’t Just My Struggle. Conclusions: Returning to work within the first two years postpartum is shaped by financial necessity, identity negotiations, disrupted sleep, and highly variable workplace support. Findings highlight the need for compassionate, flexible, and inclusive workplace policies that recognise the ongoing caregiving demands of new mothers and support their health and wellbeing during this transition.

While advances in behavioural and neuroimaging methods suitable for use with infants have greatly increased our understanding of infant brain function, cognition and behaviour in recent years, relatively little is known about the rapid period of development during the last trimester of pregnancy and first weeks and months after birth, as well as the roles that the social environment and stress play in shaping this development. This protocol paper outlines The UK Perinatal Imaging in Partnership with Families (PIPKIN) Study, a unique, multi-method, longitudinal cohort study investigating the early development of fetal and infant neurocognitive function and behaviour, and how the infant’s social and family environment shapes this development. The study follows families from a range of socio-economic backgrounds who participate at ten timepoints, from the third trimester of pregnancy until their infant is nine months old, with three visits taking place during the infant’s first postnatal month.The study harnesses recent methodological advances coupled with the drive for more ecologically valid data collection by undertaking many of these visits in families’ homes. Methods include measures of fetal behaviour using 4D ultrasound scanning; infant brain imaging using fNIRS and EEG; a full-day video recording of the home environment from the infant’s perspective, with physiological measures; measures of recent stress in both infant and mother; questionnaires relating to the home environment as well as parents’ feelings, attitudes, health and parenting routines; and standardised measures of infant behaviour and development.Specific aims are to investigate: i) individual differences in basic sensory, behavioural and motor processing between late prenatal and early postnatal periods; ii) rapid change in cortical functions over the first month, particularly for brain networks that support social behaviour; iii) effects of social interaction on developing brain function; and iv) individual differences in developmental trajectories associated with poverty-related contextual factors.

We thank Dr Alves for his comments on our paper entitled “Flavor Sensing in Utero and Emerging Behaviors in the Human Fetus” (Ustun et al., 2022). As we acknowledge and Dr Alves highlights, the behavioural responsiveness of the human fetus to chemosensory stimuli delivered in utero has so far been rarely investigated in utero, contrary to rat or ovine fetuses, which behavioural and psychophysiological reactions could be more extensively assessed using chemostimuli applied directly in the womb (e.g., Robinson et al., 1995; Schaal et al., 1991; Smotherman & Robinson, 1987). Rather most studies rely on a posteriori evidence with infants being re-exposed to chemostimuli which they could “only” have experienced prenatally. Therefore, many of the biological and psychobiological issues raised by Ustun et al.’s study need further work. Specifically, on 1) chemoreceptor system(s) and 2) brain structures and cognitive processes involved, on 3) the nature, kinetics and pathways of exogenous chemostimuli that reach fetal chemoreceptors, and on 4) the nature and timing of fetal responses. In this letter, we reply to Dr Alves’s comments.

Throughout pregnancy, fetuses are exposed to a range of chemosensory inputs influencing their postnatal behaviors. Such prenatal exposure provides the fetus with continuous sensory information to adapt to the environment they face once born. This study aimed to assess the chemosensory continuity through a systematic review and meta-analysis of existing evidence on chemosensory continuity from prenatal to first postnatal year. Web of Science Core. Collections, MEDLINE, PsycINFO, EBSCOhost ebook collection was searched from 1900 to 2021. Studies identified from the search were grouped according to type of stimuli the fetuses were exposed to prenatally that the neonatal infants’ responses to were being evaluated, namely flavors transferred from the maternal diet, and the odor of their own amniotic fluid. Of the 12 studies that met the eligibility criteria for inclusion (k = 6, k = 6, respectively in the first and the second group of studies), and eight studies (k = 4, k = 4, respectively) provided sufficient data suitable for meta-analysis. Infants, during their first year of life, oriented their heads for significantly longer durations in the direction of the prenatally experienced stimuli with large pooled effect sizes (flavor stimuli, d = 1.24, 95% CI [0.56, 1.91]; amniotic fluid odor, d = 0.853; 95% CI [.632, 1.073]). The pooled effect size for the duration of mouthing behavior was significant in response to prenatal flavor exposure through maternal diet (d = 0.72; 95% CI [0.306, 1.136]), but not for the frequency of negative facial expressions (d = -0.87, 95% CI [-2.39, 0.66]). Postnatal evidence suggests that there is a chemosensory continuity from fetal to the first year of postnatal life.

The diet of pregnant women exposes fetuses to a variety of flavors consisting of compound sensations involving smell, taste, and chemesthesis. The effects of such prenatal flavor exposure on chemosensory development have so far been measured only postnatally in human infants. Here, we report the first direct evidence of human fetal responsiveness to flavors transferred via maternal consumption of a single-dose capsule by measuring frame-by-frame fetal facial movements. Pregnant women and their fetuses based in the northeast of England were involved in this study from 32 to 36 weeks’ gestation. Fetuses exposed to carrot flavor ( n = 35) showed “lip-corner puller” and “laughter-face gestalt” more frequently, whereas fetuses exposed to kale flavor ( n = 34) showed more “upper-lip raiser,” “lower-lip depressor,” “lip stretch,” “lip presser,” and “cry-face gestalt” in comparison with the carrot group and a control group not exposed to any flavors ( n = 30). The complexity of facial gestalts increased from 32 to 36 weeks in the kale condition, but not in the carrot condition. Findings of this study have important implications for understanding the earliest evidence for fetal abilities to sense and discriminate different flavors.