Is March’s child full of woe? A growing body of evidence suggests that the season in which a baby is born may affect everything from eyesight and eating habits to the risk of developing both mental and physiological problems later in life. A recent study reveals that our season of birth makes persistent and lasting changes to brain structures that influence our health, personality and behavior.

The season of birth (SOB) effect has been recognized since as early as 460 BC with the musings of Hippocrates, and has continued to be documented by modern research. Unlike astrology, however, these studies use scientific methodology to investigate and further understand the relationship between SOB and physiological and psychological traits, disorders and diseases.

The latest SOB cohort study, involving over 3 million people born in Sweden, identified that babies born in spring had a significantly increased risk of developing cutaneous malignant melanoma. The researchers suggest that sun avoidance may be critical during the first few months of life in determining your ultraviolet radiation susceptibility. Similarly, for those living in northern hemispheres, seasonal differences in UV light exposure and associated maternal vitamin D levels are linked with spring babies’ higher risk of multiple sclerosis (MS).

When it comes to neurobehavioral disorders, statistically significant associations have been made between SOB and the prevalence of schizophrenia, bipolar disorder and panic disorder, as well as traits such as lifespan, suicidality and novelty and sensation seeking. While proposed causal factors are likely combinatorial in nature, including differences in temperature, light, nutrition, maternal hormones and egg quality, new evidence indicates that these environmental variables impact brain development, with structural changes to the brain persisting through to adulthood.

Although many structural differences, both broad and discrete, were identified in the brains of those born in different months, the strongest overall effect was observed in the auditory cortex of males born in spring and summer. Compared with those born in fall and winter, these individuals had a smaller left superior temporal gyrus. Interestingly, this is a consistently replicated neuroanatomical feature of schizophrenia, especially suicide prone schizophrenics and is also a more prominent feature in individuals with suicidal depression, as opposed to those with non-suicidal depression. Again this highlights the link between spring-early summer babies and their increased likelihood of having neurobehavioral problems in adulthood.

So is there an ideal month to give birth when the health and wellbeing of your future child is concerned? Perhaps. Although there are records of autumn and early winter babies being prone to asthma, babies born in late winter through spring and into early summer draw the shortest straw as, collectively, they are at higher risk of developing a larger number of health issues from eating and mental disorders to cancer, Parkinson’s disease and MS.

In defence of all spring and summer babies out there, there has been a loose association between being born in spring and summer and being more of a novelty-loving, adventurous thrill-seeking type and it should be noted that there have been few studies on the SOB effect and more positive aspects of psychology, such as humor or creativity.

Oddly enough “March’s child being full of woe” seems to be in stark contradiction with our perception of springtime being the season of new birth. Thankfully, with the majority of human births in the world occurring in autumn, we seem to be inadvertently using the SOB effect to our advantage.

References

Crump C, Sundquist K, Sieh W, Winkleby MA, & Sundquist J (2014). Season of birth and other perinatal risk factors for melanoma. International journal of epidemiology PMID: 24453238

Dobson R, Giovannoni G, & Ramagopalan S (2013). The month of birth effect in multiple sclerosis: systematic review, meta-analysis and effect of latitude. Journal of neurology, neurosurgery, and psychiatry, 84 (4), 427-32 PMID: 23152637

Pantazatos SP (2013). Prediction of individual season of birth using MRI. NeuroImage, 88C, 61-68 PMID: 24246490

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