There is no universally accepted explanation for this drop as of August 2020. Hypotheses include additional rest and support for expectant mothers staying at home, less air pollution due to shutdowns and reduced car fumes, and reduced likelihood of catching other diseases and viruses in general due to the lockdowns. Research
Brain injury is common among preterms, ranging from white matter injury to intraventricular and cerebellar haemorrhages. The characteristic neuropathology of preterms has been described as the "encephalopathy of prematurity". The number of preterms that receive special education is doubled compared to the general population. School marks are lower and so are verbal learning, executive function, language skills, and memory performance scores, as well as IQ scores. Behaviourally, adolescents who were born very preterm and/or very low birth weight have similar self-reports of quality of life, health status and self-esteem as term controls.Various structural magnetic resonance studies found consistent reductions in whole brain volume. The extensive list of particular regions with smaller volumes compared to controls includes many cortical areas (temporal, frontal, parietal, occipital and cingulate), the hippocampal regions, thalamus, basal ganglia, amygdala, brain stem, internal capsule, corpus callosum and cerebellum. Brain volume reduction seems to be present throughout the whole brain. In contrast, larger volumes were found in some of the same areas including medial/anterior frontal, parietal and temporal cortex, cerebellum, middle temporal gyrus, parahippocampal gyrus, and fusiform gyrus, as well as larger lateral ventricles on average. The cause of these inconsistencies are unknown.
Of these children, 46 percent had moderate to severe disabilities such as cerebral palsy, vision or hearing loss and learning disabilities, 34 percent had mild disabilities, and 20 percent had no disabilities. 12 percent had disabling cerebral palsy. Up to 15 out of 100 premature infants have significant hearing loss.As survival has improved, the focus of interventions directed at the newborn has shifted to reduce long-term disabilities, particularly those related to brain injury. Some of the complications related to prematurity may not be apparent until years after the birth. A long-term study demonstrated that the risks of medical and social disabilities extend into adulthood and are higher with decreasing gestational age at birth and include cerebral palsy, intellectual disability, disorders of psychological development, behavior, and emotion, disabilities of vision and hearing, and epilepsy. Standard intelligence tests showed that 41 percent of children born between 22 and 25 weeks had moderate or severe learning disabilities when compared to the test scores of a group of similar classmates who were born at full term. It is also shown that higher levels of education were less likely to be obtained with decreasing gestational age at birth. People born prematurely may be more susceptible to developing depression as teenagers. Some of these problems can be described as being within the executive domain and have been speculated to arise due to decreased myelinization of the frontal lobes.