The early years are a critical time of development during which multiple transformations take place for both infant and family. Infants experience enormous brain development ante- and postnatally, making them both highly receptive and highly vulnerable to environmental influence. For example a recent review suggested that ‘the fetal period is ripe for renewed focus in child psychiatric conditions. The field of developmental origins has come into its own in much of medicine, with strong programs of research investigating fetal and placental effects related to subsequent heart disease, diabetes mellitus, and cancer’ [1]. Families, and especially mothers, experience multiple changes that may have a lasting impact on their well-being and on the development of their child. This chapter will describe how a better understanding of the trajectory of individuals during the perinatal period provides rich entry point for trying to prevent perinatal psychiatric disorders, early relationship disorders and child psychiatric conditions.

The transition to parenthood is a developmental crisis. The future mother experiences profound neurohormonal, intrapsychic and interpersonal challenges that redefine her sense of identity and her capacity for intimacy and nurturing. This intense period involves reworking attachment relationships, reconsidering one’s identity to accommodate the parental role, experiencing various losses, transforming marital intimacy, establishing a parental alliance, defining the ideals and goals of becoming a new parent, and reconsidering one’s family and cultural heritage. The parental alliance gets progressively established in the context of various types of behavioural and socioemotional interactions within the family.

During pregnancy and the first year of their child’s life, parents normally encounter a broad range of affects: feelings of joy, awe and wonder, but also of strangeness, ambivalence and helplessness. Self-doubts about the capacity to nurture a child and feelings of ambivalence towards the infant or the marital partner are also part of the experience. Postnatally, as mutual affective regulation gets established in the family system, both parents and infant become better able to enjoy their interaction and to repair their communicative difficulties. This period brings about new strengths but also new vulnerabilities in parents, including the onset or exacerbation of psychiatric disorders. If psychopathology surfaces during this period, not only will the mother suffer from her condition but she will also be affected in her parental role through changes of affects, perceptions and behaviours.

Multiple longitudinal studies have shown that various childhood conditions, notably aggressive behaviour and even some child psychiatric conditions, can be prevented when intervention starts early and even antenatally [2]. Indeed, intervening early during pregnancy allows the establishment of a therapeutic alliance with vulnerable families and helps parents increase their sense of security during this period.

The attachment literature has demonstrated that attachment patterns are transmitted across generations but also that transmission gets established very early, even antenatally. For example in a seminal and replicated study, maternal attachment organisation was assessed during pregnancy and was shown to predict mother–infant attachment at 1 year of age [3].

At the family level, triadic interactions between mother, father and child have also been shown antenatally and significantly predict the postnatal triadic interactions [4]. This data points towards the possibility of intervening antenatally with the family, not only to improve parental well-being and to facilitate the parental alliance, but also to directly help the triadic relationship with the infant.

Prenatal characteristics of the infant, such as sex, the presence of multiple foetuses or various medical conditions also impact the early relationship. Parents develop internal representations of their infants antenatally and these representations influence how the parent behaves towards the infant. Studies with the Working Model of the Child Interview have shown that parental representations of the unborn infant – considering for example richness or distortions of representations – were linked to infant perception postnatally, hence influencing the various levels of parent–infant interactions postnatally [5].

The infant is very interactive after birth and the characteristics of the infant will be very influential on the early parental affective states and vice versa. This concept has been extensively studied through the transactional model of development. Hence infants born with various risk factors such as a difficult temperament, ‘colic’, medical problems or various neurosensory difficulties will create specific challenges to the ‘goodness-of-fit’ between parent and infant.

In various cultures, traditional beliefs have emphasised the importance of protecting both mothers and foetuses against negative or stressful life events. This important intuition has been borne out by an increasing number of empirical studies clarifying the role of stress on maternal and infant neurodevelopmental outcomes.

Social stress is central to stressful environmental circumstances; it includes migration, racial discrimination, domestic violence, trauma, young or advanced maternal age. In addition, special clinical obstetrical circumstances will lead to a higher risk of psychiatric complications. These include pregnancy after perinatal loss or infertility, high-risk pregnancy (including multiple pregnancy), perinatal trauma, prematurity, foetal conditions or early temperamental difficulties in infants.

The perinatal stress literature has emphasised the role played by elevated transplacental cortisol. Cortisol is a hormone that is essential for the development of the foetal central nervous system. It crosses the placental barrier after being metabolised and ‘buffered’ by a placental dehydrogenase. An increasing number of prospective, well-controlled studies – but not all – have found that foetal exposure to elevated cortisol is associated with a higher risk of negative neurodevelopmental outcomes in infants. These effects range from emotional, cognitive, motor and language effects, in addition to a higher risk of childhood and adolescent conditions such as ADHD or conduct disorder [6]. In these studies, the link between antenatal stress and outcomes still holds after many confounding variables are controlled, such as life habits, SES and postnatal depression. More recently, studies have suggested that not all foetuses are affected equally and that the epigenetic impact of stress on the developing foetus could be related to genetic predispositions, notably the variants of the serotonin transporter gene. Moreover, developmental outcomes are strongly modulated by the quality of the attachment relationship [7].

The risk of elevated stress not only affects maternal and family well-being but also obstetrical follow-up and outcomes. Multiple studies suggest an increased risk of low birth weight, preterm delivery and pregnancy complications [8].

Although the effects of stress appear to be significant on infant neurodevelopment, the effects of stress are neither linear nor necessarily clinical. Indeed many clinical situations demonstrate apparently few observable effects on the infants, tending to confirm the fact that infants are neuroplastic and able to recover well. Hence, expectant mothers should not be made to feel guilty. However, this data highlights that stress should be considered a risk factor that justifies preventive maternal and familial interventions.