New research suggests that the season a woman was born in could influence their health later in life, Yahoo Health reported.
Researchers from the University of Cambridge found that women who were born in the summer are more likely to be healthy adults. They believe that more sunlight -- and therefore higher vitamin D exposure -- in the second trimester of pregnancy could explain the effect.
"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," Dr. John Perry, lead author of the study, said in a statement.
For the study, researchers collected and analyzed data from around 450,000 men and women from the UK Biobank study, a major national health resource that provides data on UK volunteers to shed light on the development of diseases.
They found that babies born in June, July, and August were heavier at birth and taller as adults, The Examiner reported. For the first time, the study also revealed that girls born in the summer started puberty later -- an indication of better health in adult life.
"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 researchers believe that the differences between babies born in the summer and the winter months could be down to how much sunlight the mother gets during pregnancy, since that in part determines her vitamin D exposure.
"We don't know the mechanisms that cause these seasons 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 findings are detailed in the journal Heliyon.