Summer Babies Are Healthier As Adults, Study Finds

Scientists find that women born in the warm summer months are healthier as adults than others.

The study showed that more than half a million people disclosed that sunlight and higher levels of vitamin D exposure benefits the third trimester of pregnancy, Elsevier  reported.

The month when she is born affects not only her birth weight but also the year of puberty, which influences her later life. Summer children showed heavier birth weights on average and a later puberty onset than winter babies.

"When you were conceived and born occurs largely 'at random' - it's not affected by social class, your parents' ages or their health - so looking for patterns with birth month is a powerful study design to identify influences of the environment before birth," said John Perry, lead author of the study.

Scientists compared the growth and development of 450,000 men and women from the UK Biobank study, discovering that babies born in June, July, and August showed heavier birthweights and more height during adulthood.

This was the first study to disclose that summer-born girls had earlier puberty than others.

"This is the first time puberty timing has been robustly linked to seasonality," Perry said. "We were surprised, and pleased, to see how similar the patterns were on birth weight and puberty timing. Our results show that birth month has a measurable effect on development and health, but more work is needed to understand the mechanisms behind this effect."

The linking is directly related to the Vitamin D from sunlight impacting expectant mothers.

"We don't know the mechanisms that cause these season of birth patterns on birth weight, height, and puberty timing," Perry said. "We need to understand these mechanisms before our findings can be translated into health benefits. We think that vitamin D exposure is important and our findings will hopefully encourage other research on the long-term effects of early life vitamin D on puberty timing and health."

The study was published in a recent edition of the journal Heliyon.