New frontiers in fetal and infant psychology

The development of new methods of investigation of brain and cognitive development have revealed amazing learning abilities in infants even before they can talk or walk. At the same time, this research has revealed great sensitivity to adversity, where brain development and learning are affected by exposure to early life harshness. The case of institutionalised children comes to mind. Extreme lack of care, poor nutrition and abuse means that even if placed into foster care, many children show brain structural modifications and associated emotional difficulties (Tibu, Humphreys, Fox, Nelson, & Zeanah, 2014). It also became clear that the origin of these impairments may precede birth. The growing evidence for a prenatal origin of mental health problems and new opportunities to study development in the womb or in preterm babies open a new frontier in developmental research.

There is now unequivocal evidence that both psychological stressors, such as traumatic life events, or biological stressors, such as alcohol or tobacco exposure, can affect the physical and intellectual growth of the developing child. For example, infants whose mothers experienced the dramatic 1998 ice storm in Canada had smaller birth weight and lower mental ability scores as toddlers (Laplante et al., 2004). However, even more common events, such as a divorce or the death of someone close, during pregnancy were shown to be associated with an increase in the incidence of developmental disorders, including ADHD or autism (Ronald, Pennell, & Whitehouse, 2011). Animal models have helped identify some of the potential biological mechanisms mediating these effects. We know that maternal stress increases corticotropin-releasing hormone production and reduces the expression of the 11B-HSD2 enzyme (Welberg, Thrivikraman, & Plotsky, 2005). This enzyme, produced by the placenta, typically acts as a selective barrier against maternal hormones. As a result of this double blow, the fetus is exposed to high amounts of corticoid hormones. Both fetal amygdala and the hippocampus, rich in glucocorticoid receptors, will suffer from this hormonal wave. Much of this interesting research still comes from animal models, but some confirmatory evidence from retrospective studies of children exposed to prenatal stress has emerged recently, showing atypical hippocampal and amygdala growth later in childhood (Buss et al., 2012). When these differences emerge, why certain babies are more susceptible to harsh environments than others, and whether the effect of prenatal stress can be mitigated by providing adequate prenatal and postnatal care are only a few of the pressing questions which will have to be answered by future research.

Although mortality following preterm birth has decreased, follow-up studies show that a large proportion of preterm infants will experience developmental and psychosocial problems throughout childhood and lifelong mental health problems (Johnson & Marlow, 2014). Despite a worrying prognosis, we still know surprisingly little about the impact that leaving the intrauterine environment earlier has on brain development and about what type of environment needs to be created for the premature baby to thrive. Being able to measure functional brain activity at the same gestational age, in the fetus and the premature baby, will tell us whether any functions have been affected by birth before term. Also, better appreciation of the sensory environment of the fetus (e.g. sounds but also touch and proprioceptive stimulation) and how they process this information will help us understand which aspects of the postnatal environment of a premature baby are beneficial and which detrimental.

How we can reveal fetal brain development in non-invasive ways is a big challenge, but one that seems less insurmountable with recent technological advances. Both ultrasound and fetal MRI can now access fetal brain structures and normative brain growth charts will soon be available (Clochoux et al., 2012; Gindes et al., 2015). In vivo markers of placental insufficiency and fetal brain development might soon be used in concert with MRI. This will allow mapping of the effects of maternal stress at different time points in fetal development. Eventually, charts that span the prenatal to postnatal development might be developed that will improve the assessment of rate of growth. Magnetoencephalography has already been used to measure neonatal brain functioning, and more recently, similar paradigms were used to measure fetal brain responses. In the first study of this kind, Schleger et al. (2014) showed evidence for sound numerosity discrimination in last trimester fetuses. More studies will follow, using more and more sophisticated paradigms. More sophisticated behavioral monitoring will also give a better picture of very early abilities. Anticipatory mouth opening before touch, a behaviour that indexes some level of information integration, was captured with 4D ultrasound (Reissland, Francis, Aydin, Mason, & Schaal, 2014). Indirect means for measuring ability before birth have been developed, for example by exposing the fetus to different types of stimulation and measuring learning after birth. Different manipulation of the learning situation (when the mother is stressed/relaxed, when the fetus is awake) will bring further information about early learning abilities.

The next step will be to use these findings for tailoring intervention to the particular needs and abilities of infants experiencing harshness or developmental atypicalities. Many interventions focused on postnatal development, especially at improving maternal sensitivity in interaction with her baby or decreasing maternal health problems. However, in recognition that stress in pregnancy has a negative impact on both the mother and the baby, there has been a rise in prenatal interventions, again aimed at decreasing maternal stress (e.g. by increasing mindfulness; Guardino et al., 2014) or enhancing maternal–fetal attachment. Equally, interventions that are more directly targeted at the unborn child, as for example by increasing understanding of fetal abilities to perceive, react and learn, could have a positive impact on the well-being of both mother and baby by supporting behavioural change such as avoiding stressors (noise, substances, conflict) and generally promoting better maternal health. The same methods that are used to investigate the fetal brain have been shown to have a transformative effect on parents, as for example experiencing and understanding fetal behaviour as revealed by 4D ultrasound (Honemeyer & Kurjak, 2014).

These recent developments in early assessment and intervention hold much promise and highlight how unsatisfactory our current efforts are in providing support for high-risk infants. Infant assessment in clinical settings using standardised developmental tests is not always routine and often occurs after the baby is a year old, which feels too little, too late. Even with our current knowledge more could be done. For example, novel tests of early attention and pre-executive functioning have been developed in psychology laboratory settings which could be developed further for clinical use. However, pushing back the frontier to prenatal development is where the greatest prospects now lie. Pregnancy is an important time for women and their families as it provides a rare opportunity for continuous engagement with the health care system in such a way that can maximise health and well-being. Current technology, developments in fetal and infant psychology research and opportunities in health care suggest that refocusing our efforts to the prenatal period holds the biggest potential for change.

Teodora Gliga
Centre for Brain and Cognitive Development, Birkbeck College, London, UK
Fiona Alderdice
School of Nursing and Midwifery, Queens University Belfast, Belfast, UK