Birth dates with a warning. Environmental conditions, infections, light exposure and even the availability of certain nutrients can all affect a baby's development. Here, we shows how much influence the seasons can have on babies . . .
SUDDEN INFANT DEATH SYNDROME
Sudden Infant Death Syndrome (SIDS) is the most common cause of the death of babies under a year old.
Several factors have been implicated, although the exact mechanism behind cot death has not yet been established.
Professor Peter Helms, of Aberdeen University's Medical School, is an expert on the effects of seasonality. He says: 'Babies born between February and May are at significantly lower risk of SIDS than babies born between August and November.'
More cot deaths occur during the winter months and the most susceptible age is between two and four months, putting September babies at greatest overall risk.
During the summer, only a third of the number of winter deaths take place, making April the least risky birth month.
Professor Helms adds: 'Even though there are statistical differences between the times of greatest and least risk, the overall numbers are very small, so no one should be unduly worried if their baby is due in September.'
Ann Deri-Bowen, of the Cot Death Association, says: 'The seasonal differences have reduced since our campaign started. But most important of all is to follow our advice - place babies on their backs, don't let them overheat, don't use duvets and don't smoke either during or after pregnancy.'
SCHIZOPHRENIA
Numerous studies have shown that schizophrenics tend to be born in late winter and early spring.
Robin Murray, Professor of Psychological Medicine at the Institute of Psychiatry, says: 'There is a real seasonal influence. Between January and April numbers peak at 10 pc above average, but then rates decline to 10 pc below average between August and October. 'In the second half of pregnancy, the connections between neural cells in the brain cortex are made. If the mother gets a feverish illness during the latter half of pregnancy, it may disturb these growing neural connections.
'Most doctors think that schizophrenia arises when these neural networks are slightly faulty, and that later in life, when you are under stress, it triggers the illness.
'There is much evidence supporting the idea that winter illnesses such as viral infections, influenza and fevers during the second half of pregnancy can increase the chances of a baby developing schizophrenia. We also know that malnourished mothers are at greater risk of having a baby who develops schizophrenia.
'In the UK, one in every 100 people gets schizophrenia. Your risk doubles to two in every 100 if you are in your mother's womb in winter and she contracts a feverish illness. It's enough to interest statisticians but shouldn't worry the general population.'
Seasonal variations have also been noted in autism, peaking in March, and major depression, which peaks between March and May.
The decrease in natural daylight in winter may play a part. Fluctuations of the hormone melatonin - known as the hormone of darkness, because it is triggered by the shortening days of winter - are thought to be involved. BRONCHIOLITIS is a serious infection of the small airways deep inside the lung, which can trigger asthma. Affecting babies under 18 months, it can be brought on by different viruses, many of which normally cause nothing more serious than a cold.
Paediatrician Dr Harvey Mar-covitch says: 'Bronchiolitis has an annual epidemic between November and March. It starts off like a cough or cold, but rapidly progresses deep into the small tubes of the lung, resulting in severe breathing difficulties, and some babies die from it. The younger you are, the worse it tends to be.
'If you're born in March or April, you're already eight months old by the time the yearly epidemic starts, and therefore stronger than babies born in August and September, who would be only two to three months old.
'If parents have asthma or eczema, and therefore have a high risk of having an asthmatic child, they may want to know that by having their child in early spring they will at least be giving it the best chance of avoiding bronchiolitis and perhaps avoid triggering asthma.'
SPINA BIFIDA
Spina Bifida is a congenital condition caused when the spinal column and surrounding tissues fail to form properly. It tends to run in families, although a lack of folic acid during the crucial first month of pregnancy, when the spinal structures are being formed, has been implicated.
Researchers have found evidence of seasonal variance in spina bifida, with more cases occurring with babies born in January and fewer among those born in July.
Professor Helm says: 'One reason may be that women who conceive in the early spring are lacking in folic acid, due to the fact that fresh fruit and vegetables have been in shorter supply during winter and early spring.'
If this theory is valid, the seasonality of spina bifida should fade as more women of childbearing age take countermeasures to prevent it by using folic acid supplements all year round.
ACADEMIC PERFORMANCE
A child born in late summer will be among the youngest in the class, and at a disadvantage compared with those born almost a year before.
Gaynor Sbuttoni, an educational psychologist, says: 'Academically, it is probably better to be born in early autumn. Socially and emotionally, the difference between the youngest and the eldest in a class can be huge and it can be hard for the younger ones to cope.
However, at puberty the eldest might get teased for being developed, but the youngest may be taunted for being underdeveloped. In this situation, children born between January and March fare best.'
Even IQ isn't immune to seasonal effects - studies in the Sixties revealed that there was a higher incidence of retardation (where the IQ fell below 70) among winter babies. ( dailymail.co.uk )
