A systematic review of human paternal oxytocin: Insights into the methodology and what we know so far

Sensitive responsiveness in expectant and new fathers

Fathers have an increasingly important role in the family and contribute through their sensitive responsiveness to positive child development. Research on parenting more often included fathers as caregivers in the past two decades. We present a neurobiological model of sensitive responsive parenting with a role for fathers' hormonal levels and neural connectivity and processing of infant signals. We tested this model in a research program ("Father Trials") with correlational and randomized experimental studies, and we review the results of these studies. So far, interaction-focused behavioral interventions seem most promising in supporting fathers' sensitive responsiveness, even though the mechanisms are still uncharted.

Prolactin and oxytocin: potential targets for migraine treatment

Migraine is a severe neurovascular disorder of which the pathophysiology is not yet fully understood. Besides the role of inflammatory mediators that interact with the trigeminovascular system, cyclic fluctuations in sex steroid hormones are involved in the sex dimorphism of migraine attacks. In addition, the pituitary-derived hormone prolactin and the hypothalamic neuropeptide oxytocin have been reported to play a modulating role in migraine and contribute to its sex-dependent differences. The current narrative review explores the relationship between these two hormones and the pathophysiology of migraine. We describe the physiological role of prolactin and oxytocin, its relationship to migraine and pain, and potential therapies targeting these hormones or their receptors.In summary, oxytocin and prolactin are involved in nociception in opposite ways. Both operate at peripheral and central levels, however, prolactin has a pronociceptive effect, while oxytocin appears to have an antinociceptive effect. Therefore, migraine treatment targeting prolactin should aim to block its effects using prolactin receptor antagonists or monoclonal antibodies specifically acting at migraine-pain related structures. This action should be local in order to avoid a decrease in prolactin levels throughout the body and associated adverse effects. In contrast, treatment targeting oxytocin should enhance its signalling and antinociceptive effects, for example using intranasal administration of oxytocin, or possibly other oxytocin receptor agonists. Interestingly, the prolactin receptor and oxytocin receptor are co-localized with estrogen receptors as well as calcitonin gene-related peptide and its receptor, providing a positive perspective on the possibilities for an adequate pharmacological treatment of these nociceptive pathways. Nevertheless, many questions remain to be answered. More particularly, there is insufficient data on the role of sex hormones in men and the correct dosing according to sex differences, hormonal changes and comorbidities. The above remains a major challenge for future development.

Proximate and Ultimate Mechanisms of Human Father-child Rough-and-tumble Play

The aim of this contribution is to attempt to understand the adaptive functions of father-child rough-and-tumble play (RTP) in humans. We first present a synthesis of the known proximate and ultimate mechanisms of peer-peer RTP in mammals and compare human parent-child RTP with peer-peer RTP. Next, we examine the possible biological adaptive functions of father-child RTP in humans, by comparing paternal behavior in humans versus biparental animal species, in light of the activation relationship theory and the neurobiological basis of fathering. Analysis of analogies reveals that the endocrine profile of fathers is highly variable across species, compared to that of mothers. This can be interpreted as fathers' evolutionary adjustment to specific environmental conditions affecting the care of the young. Given the high unpredictability and risk-taking features of RTP, we conclude that human adult-child RTP appears to have a biological adaptive function, one of 'opening to the world'.

Influence of oxytocin on parenting behaviors and parent-child bonding: A systematic review

Oxytocin (OT) plays a pivotal role in early parent-child relationship formation and bonding that is critical for the social, cognitive, and emotional development of the child. Therefore, this systematic review aims to consolidate all available evidence regarding the associations of parental OT concentration levels with parenting behavior and bonding within the past 20 years. A systematic search was conducted in five databases from 2002 to May 2022, and 33 studies were finalized and included. Due to the heterogeneity of the data, findings were presented narratively based on the type of OT and parenting outcomes. Current evidence strongly suggests that parental OT levels are positively related to parental touch and parental gaze and affect synchrony and observer-coded parent-infant bonding. No gender difference in OT levels was observed between fathers and mothers, but OT strengthens affectionate parenting in mothers and stimulatory parenting in fathers. Child OT levels were also positively associated with parental OT levels. Family and healthcare providers could encourage more positive touch and interactive play between parent and child to strengthen parent-child relationships.

Neuroscience-based psychotherapy: A position paper

In the recent years, discoveries in neuroscience have greatly impacted upon the need to modify therapeutic practice starting from the evidence showing some cerebral mechanisms capable of coping with mental health crisis and traumatic events of the individual's life history by redesigning the narrative plot and the person's sense of the Self. The emerging dialogue between neuroscience and psychotherapy is increasingly intense and modern psychotherapy cannot ignore the heritage deriving from studies about neuropsychological modification of memory traces, neurobiology of attachment theory, cognitive mechanisms involved in psychopathology, neurophysiology of human empathy, neuroimaging evidence about psychotherapeutic treatment, and somatoform disorders connecting the brain and the body. In the present article, we critically examined sectorial literature and claimed that psychotherapy has to referred to a neuroscience-based approach in order to adopt the most tailored interventions for specific groups of patients or therapy settings. We also provided recommendations for care implementation in clinical practice and illustrated challenges of future research.

Hormonal and behavioral responses to an infant simulator in women with and without children

We investigated the impact of maternal status on hormonal reactivity and behavioral responses to an infant simulator in 117 women (54 primiparous, 63 nulliparous). The amount of affectionate touch and motherese were analyzed as behavioral measures of caregiving. Saliva was collected before and 10 min after interaction with the infant simulator to analyze oxytocin, testosterone, cortisol, and estradiol levels. Nulliparous women also provided information about their fertility motivation. Linear mixed models indicated that greater use of affectionate touch was associated with lower overall testosterone levels. Cortisol decreased in response to the interaction in both groups. In the primiparous group, the amount of affectionate touch associated inversely with cortisol levels, whereas in the nulliparous group such association was not found. Oxytocin or estradiol reactivity to the simulator did not differ between the groups, nor were these hormones associated with behavior. Higher fertility motivation in nulliparous women was related to more motherese, and lower testosterone levels. Our results indicate that the simulator elicits hormonal reactivity both in mothers and nonmothers, but the patterns of associations between caregiving behavior and hormonal levels may be partially different. These results encourage using the infant simulator to explore hormonal processes related to the transition to parenthood.

Sex-dependent association between variability in infants' OXTR methylation at birth and negative affectivity at 3 months

BACKGROUND

Sex-specific differences in DNA methylation of the oxytocin receptor gene (OXTR) have been shown in adults and are related to several mental disorders. Negative affectivity early in life is a trans-diagnostic risk marker of later psychopathology and is partly under genetic control. However, sex-specific variations in OXTR methylation (OXTRm) in infants and their associations with negative affectivity are still unknown.

AIMS

Here, we explored sex differences in the association between infant OXTRm at birth and negative affectivity at 3 months of age.

METHODS

Infants and their mothers (N = 224) were recruited at delivery. Infants' methylation status was assessed in 13 CpG sites within the OXTR gene intron 1 region (chr3: 8810654-8810919) in buccal cells at birth while 3-month-old infants' negative affectivity was assessed by mothers using a well-validated temperament questionnaire.

RESULTS

OXTRm at 12 CpG sites was higher in females than in males. Moreover, higher infants' OXTRm at 6 specific CpG sites was associated with greater negative affectivity in males, but not in females.

CONCLUSIONS

These results provide new insights into the role of sex-dependent epigenetic mechanisms linking OXTRm with early infants' emotional development. Understanding the degree to which epigenetic processes relate to early temperamental variations may help inform the etiology of later childhood psychopathological outcomes.

Is paternal oxytocin an oxymoron? Oxytocin, vasopressin, testosterone, oestradiol and cortisol in emerging fatherhood

How do hormonal levels in men change from pregnancy to after the birth of their firstborn child, and what is the role of oxytocin, alone or in interplay with other hormones, in explaining variance in their parenting quality? We explored in 73 first-time fathers the development of five hormones that have been suggested to play a role in parenting: oxytocin (OT), vasopressin (AVP), testosterone (T), oestradiol (E2) and cortisol (Cort). In an extended group of fathers (N = 152) we examined associations with fathers’ behaviour with their 2-month-old infants. OT and E2 showed stability from the prenatal to the postnatal assessments, whereas AVP and T decreased significantly, and Cort decreased marginally. OT on its own or in interplay with other hormones was not related to paternal sensitivity. Using an exploratory approach, the interaction between T and E2 emerged as relevant for fathers’ sensitive parenting. Among fathers with high E2, high T was associated with lower sensitivity. Although we did not find evidence for the importance of OT as stand-alone hormone or in interplay with other hormones in this important phase in men's lives, the interaction between T and E2 in explaining variation in paternal behaviour is a promising hypothesis for further research.

This article is part of the theme issue ‘Interplays between oxytocin and other neuromodulators in shaping complex social behaviours’.

Effects of oxytocin and vasopressin administration on human fathers' sensitive and challenging parenting: A randomized within-subject controlled trial

This randomized, double-blind, placebo-controlled within-subject study examined the effects of intranasal administration of oxytocin and vasopressin on fathers' sensitive and challenging parenting behaviors. Furthermore, we examined the moderating role of fathers' early childhood experiences. The sample consisted of 70 fathers with their 2- to 12-month-old infants. All fathers were assigned to each of the three experimental sessions (oxytocin, vasopressin, and placebo), on three separate days, with random order and intervening periods of one to two weeks. Sensitive and challenging parenting behaviors (CPB) were observed during a 10-minute free play task. Results showed no effects of vasopressin administration on paternal sensitivity. Fathers in the oxytocin condition were less sensitive than fathers in the placebo condition, and this effect was moderated by fathers' own childhood experiences: Fathers who reported higher levels of experienced parental love withdrawal were less sensitive in the oxytocin condition as compared to the placebo condition, whereas fathers with less experienced parental love withdrawal showed no difference in sensitivity between the oxytocin and placebo condition. No effects were found of oxytocin and vasopressin administration on fathers' CPB. Our results, although partly unexpected, are largely in line with previous literature showing that oxytocin administration can exert negative effects in individuals with adverse childhood experiences.

Applicability of a Novel Attunement Instrument and Its Relationship to Parental Sensitivity in Infants With and Without Visual Impairments

This study investigated the applicability of a novel instrument to assess parent–child attunement in free play interactions, in dyads with an infant with and without visual impairments (VI). We here report the findings on the reliability and applicability of the newly developed Attune & Stimulate Mother–Infant 56-items Instrument (A&S M-I) in two separate samples: one with infants with VI (N = 20) and one with typically sighted infants (N = 24). In addition, we assessed the contribution of parental sensitivity to attunement in dyadic interactions. The A&S M-I is an observational comprehensive instrument of behaviors that captures different body parts and their motility (i.e., finger movements, arm waving, and foot kicking), and different senses (i.e., audio, tactile, and visual). The appropriate responding of a parent to the child’s signal (i.e., matching and containing) reflects the ability to attune in the dyad as well as parent’s ability to stimulate the child to become engaged in the contact or activity. Consistency assessments revealed good reliability for maternal and infant behaviors, acceptable internal consistency and good test–retest reliability. Furthermore, both samples scored significantly above chance level on attunement, suggesting that the instrument captures parent–infant behavioral coordination, and VI was not related to parent–infant attunement. Lastly, a relation between parental sensitivity and attunement was found only in the TS sample. Altogether, these findings provide promising initial evidence of the applicability of the A&S M-I instrument for assessing dyadic attunement across different populations and ages. Having assessed the applicability of this observational instrument, future work should corroborate these findings in larger samples.

Do empathy and oxytocin predict responsiveness to a crying infant simulator in expecting and non-expecting couples? A multilevel study

Infant crying is a strong emotional stimulus that elicits caregiving responses in adults. Here we examine the role of empathy (measured with the Polish version of Interpersonal Reactivity Index) and salivary oxytocin in modulating sensitive responsiveness to a crying infant simulator in two groups of heterosexual couples: 111 expecting or 110 not expecting a baby. Sensitive responsiveness was observed during a standardized procedure using the Ainsworth Sensitivity Scale while participants took care of the infant simulator, both individually and as a couple. Other-oriented empathy predicted elevated levels of individual but not couple sensitive responsiveness. More OT reactivity to crying predicted less responsiveness in non-expecting couples, which might be explained by their stronger focus on task performance. This study uniquely combined hormonal, observational and self-report measures in couples, and showed that personality and hormonal correlates of sensitive responsiveness might be studied before the child's birth with the use of infant simulators.

Exploring the role of endocrine factors in sensitive parenting in men

Parental sensitivity has been studied extensively in parenting research. Recently, there has been increasing attention to endocrine factors that may be related to parental sensitivity, such as oxytocin, vasopressin, testosterone, and cortisol. Although hormones do not act in isolation, few studies integrated multiple hormones and examined their combined associations with parental sensitivity. The current study aimed to explore the hormonal correlates of paternal sensitivity by examining in 79 first-time fathers of young infants (2-4 months old) (1) the separate and combined associations of basal oxytocin, vasopressin, testosterone, and cortisol levels with sensitivity, and (2) the associations between paternal sensitivity and oxytocin, vasopressin, testosterone, and cortisol reactivity following father-infant interactions. We additionally explored whether interactions between the various basal hormone levels could predict paternal sensitivity. Saliva for the quantification of fathers' hormone levels was sampled before and after an interaction with their infant to determine basal levels and reactivity. Results revealed no significant associations between sensitivity and basal hormone levels or reactivity. However, results indicated that cortisol and testosterone interacted in their effects on paternal sensitive parenting. Namely, fathers with low basal cortisol levels showed more sensitivity with increasing T levels, but fathers with high cortisol levels were less sensitive with increasing T levels. However, it should be noted that the latter slope was not significantly different from zero. These findings suggest that variations in parental sensitivity might be better explained by interactions between hormones than by single hormone levels.