Spring babies may be more at risk of heart disease in later life, research suggests.
Scientists from Harvard compared the birthdays and cardiovascular health of more than 116,000 adults.
They found those born in April were 12% more likely to die of heart disease over the next 38 years than November babies.
Although unclear exactly why this may occur, the scientists suggest seasonal changes to diet, air pollution and sunlight both during pregnancy and in early life may play a role.
Well it may sound farfetched, previous studies have linked the season and month of a person’s birth to their risk of an early death and dying from heart disease specifically.
In the northern hemisphere, November babies have been shown to be the least vulnerable, while those born in May appear to be most at risk.
The scientists felt these studies failed to properly take into account other factors that could influence the results.
For example, well-off parents may plan conception to avoid giving birth during winter, they wrote in The BMJ.
Adults born into rich families may then be less at risk of heart disease and an early death.
To learn more, the scientists looked at participants of the Nurses’ Health Study. Started in 1976 in the US, the female nurses were aged 30-to-55 at the start and followed for 38 years.
Results suggest the women born in April were the least at risk of dying from heart disease.
A March birthday raised the odds by 9%, May or July 8%, and June 7%.
December babies were 5% less likely to die from heart disease than their November counterparts, the results show.
Being born in any spring or summer month raised the risk by 10% and 9%, respectively, compared to an autumn birthday.
A link was only found between a person’s birth month and their risk of dying from heart disease, not an early death by any other cause.
Why this occurs is unclear. The scientists speculate it may be due to the availability of nutritious fruit and vegetables varying throughout the year.
Babies born in November were in their second trimester during the spring and summer months, when fresh produce is more plentiful for expectant mothers.
Infections may also peak during certain seasons, triggering damaging inflammation.
Colds, flu and the norovirus tend to be more common in winter, while urinary tract infections or skin conditions like impetigo may be triggered by hot weather.
Vitamin D deficiency among pregnant women has also been linked to a greater risk of heart disease in a baby’s later life.
Those who fail to take the recommended daily supplement may find themselves lacking in the nutrient during the winter months.
The scientists stress further studies are required to confirm these results and uncover the possible mechanisms at play.