Babies Born in Summer Grow Up Healthier, Study Says


HealthyAccording to a new study published in the journal Heliyon, babies who are born in the summer months have a greater chance of becoming strong, healthy adults.

Researchers from the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge in the U.K. suggest that their findings support the “fetal programming” theory. This theory suggests that the environment in the womb leads to early life differences that can affect one’s health later in life.

To investigate their theory, the team analyzed data from the U.K. Biobank study—a major national health resource used to compare the growth and development of approximately 450,000 men and women.

Researchers discovered that babies born between June and August had higher birth weights and were taller as adults. Furthermore, girls who were born during these months started puberty later, an indicator of better health in adulthood.

Babies born between December and February showed outcomes that were “directionally opposite” to the outcomes of babies born in the summer months.

The associations were seen with the total hours of sunshine during the second trimester, but not during the initial three months after birth. There were also further associations regarding educational achievements. Those born in autumn months were more likely than those born during the summer to either continue their education past the age of 16 or achieve a degree-level qualification.

John Perry, the study’s lead author, believes that these seasonal differences may come down to how much sunlight a mother receives during pregnancy—a factor that affects the vitamin D levels.

“We don’t know the mechanisms that cause these season of birth patterns on birth weight, height, and puberty timing. We need to understand these mechanisms before our findings can be translated into health benefits,” notes Perry. “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.”

Perry concludes that this is the first study to link puberty timing with seasonality, although “more work is needed to understand the mechanisms behind this effect.”

Sources for Today’s Article:
Ellis, M., “Summer babies grow up to be healthier adults,” Medical News Today web site, October 13, 2015;
Perry, J. et al., “Season of birth is associated with birth weight, pubertal timing, adult body size and educational attainment: a UK Biobank study,” Heliyon, 2015; doi: 10.1016/j.heliyon.2015.e00031.

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