The days of believing your destiny is written in the stars are long gone (apart from a few crazy D-list celebrities). Astrology has been debunked and horoscopes are something we idly read on our lunch breaks while pretending to know what it means when the moon is in Virgo. However, recent research has discovered that the time of year you are born could have a range of impacts on your health (but probably not your compatibility with that Aries barista in Starbucks).
The seasonality of your birth can impact on your mental health, researchers from Hungary have found. They discovered that the amount of sunlight a pregnant woman receives might affect her baby’s personality later in life. Seasonal Affective Disorder (SAD) occurs when your body doesn’t receive enough sunlight, which can lead to depression and is often why people feel lethargic in wintertime. It is thought the disorder is caused by a lack of serotonin, a hormone that regulates mood, and that this shortage could also be passed onto the foetus. The researchers found that babies born in winter were more likely to have depressed moods, and those born in the spring more likely to have a positive personality. However, these effects are very small and unlikely to have a great impact on your life.
Another effect the timing of your birth may have on your mental health is your chance of developing schizophrenia. Babies born in winter and early spring (in the northern hemisphere) are more likely to develop the disorder, although the chances are still very small. Babies born near the equator have an equal chance of developing schizophrenia throughout the year. Multiple theories have been put forward as an answer to this finding, including a reduction in the amount of vitamin D a pregnant woman receives in winter.
A recent study has put forward an alternative theory that the effect of reduced sunlight on the mother’s circadian rhythms could be a cause. A circadian rhythm is the 24-hour cycle of processes that occur inside your body that might be partly controlled by the levels of sunlight you obtain at different times of the day and year. Researchers have found that these rhythms affect melatonin levels, increasing amounts of the hormone dopamine in your body. Increased levels of dopamine have been thought to cause the disorder. But there is little need to worry about the results of this study, as it reports only 10% of cases of schizophrenia are potentially due to the season of birth, and the risk of developing the disorder is incredibly small anyway.
Season of birth can also affect your overall physical health later in life. Studies in Gambia examined how malnutrition in pregnancy leads to babies born underweight and a higher risk of death in young adulthood. Gambia has a hungry season that coincides with the rains, as food from the previous harvest begins to run low and diseases become more widespread. This leads to a slowing of growth for the foetus as it struggles to gain the nutrition it needs. A lower birth weight means higher chances of succumbing to famine and is also linked to a poor immune system which impacts on later life. It’s not all bad news though, as further studies have found that giving previously malnourished mothers high-energy food supplements can greatly reduce the negative effects on the foetus.
Whilst the star sign you were born under doesn’t have much influence over your life, the season and weather conditions might. The timing of your birth has a small effect on you and is built on by environmental, social and even genetic factors that will also play a role in how you develop. So, read that horoscope, flirt with the barista and relax in the knowledge that you have absolutely no control over your life.
Ceesay, S. M.; Prentice, A. M.; Cole, T. J.; Foord, F.; Poskitt, E. M. E.; Weaver, L. T.; Whitehead, R. G. (1997) Effects on birth weight and perinatal mortality of maternal dietary supplements in rural gambia: 5 year randomised controlled trial. British Medical Journal. 315(7111), 786.
Schwartz, P. J. (2011) Season of birth in schizophrenia: A maternal–fetal chronobiological hypothesis. Medical hypotheses. 76(6), 785-793.
Winter, L. (2014) What Your Date Of Birth Says About Your Personality [online] Available from: http://www.iflscience.com/brain/does-season-birth-affect-personality [Accessed 1/11/15]