Seasons & Symptoms

How your season of birth provides important health information

Our Beloved Family:

When it comes to understanding, maintaining or recovering our health, it’s natural to take into consideration things like lifestyle habits, diet, exercise, family health history and as we’ve stated for many years, past traumas and emotional well-being. In addition to these important factors, science continues to show that one aspect of our lives holds great influence over our health and yet, we would never think to suspect that it does. It’s the season in which we were born.

A very large study of 500,000 people from the U.K. has found that certain biomarkers are “significantly associated” with season of birth to a very high degree.1 These include birth weight, rate of maturation or onset of puberty and even height in adulthood. Because of this, it’s been determined that season of birth affects childhood growth and development in important ways.

Results showed that children born in the summer (June-July-August) had higher birth weights, entered puberty or had first menstruation later and were consistently taller, especially as adults, than children born in winter months (November-December-January). Although summer babies had heavier birth weights, this did not affect their overall body mass index (BMI) later in life.

Much of these results were attributed to the in utero vitamin D the babies received from their mothers via sun exposure, particularly during the second trimester, when bones are being formed, lengthened and programmed for adult life. The influence of vitamin D on the fetus in these and other important ways was so important, the study said that it’s effect was “as powerful as any genetic determinant”. In fact, in utero vitamin D exposure proved to be far more influential to a baby’s development in adulthood than even its own sun exposure in the three months after birth.

Everything an expectant mother is exposed to affects her baby, whether it’s diet, pollution in the environment, sun exposure and even the length of the day. Many studies have been done regarding the “fetal origins of adult disease” hypothesis,2 how they’re related to the season of birth and their impact on health outcomes years later. Much research has been done connecting the season of birth to proclivities for immune disorders,3 cardiovascular disease,4 Type 15 & 26 diabetes, lifespan7 , whether you’re a morning/evening person,8 or even right or left handed.9 For example, a greater percentage of those born during autumn and the beginning of winter tend to live longer than those born during spring and summer. Interestingly, the most dramatic contrast in the U.K. study between babies born in different seasons was that of educational attainment. While it needs further study, babies born in autumn, particularly September and early October, showed a much greater degree of pursuing advanced educational attainment beyond high school.

It’s important to remember that every person is an individual, and personal overall health is made up of a composite of many factors, including those mentioned above. Even so, whether you’re investigating the mystery of a current health challenge or just want to do your best to support your existing health as you age, looking into your season of birth as it relates to health just might provide some interesting answers and strategies.

Learn why vitamin D is absolutely essential for so many biological processes that many scientists don’t consider it so much a vitamin as a hormone precursor

Light & Love in the Month Ahead,
Dr. Habib Sadeghi & Dr. Sherry Sami


(1) Day, Felix, et al, (2015), Season of birth is associated with birth weight, pubertal timing, adult body size and educational attainment: a U.K. Biobank study, Heliyon, e00031,
(2) Bhutta, Z, (2013), Maternal and child nutrition; the first 1,000 days, 74th Nestle Nutrition Institute Workshop, vol. 74, 11-25,
(3) Disanto, G. et al, (2012), Month of birth, vitamin D and risk of immune-mediated disease: a case control study, BMC Medicine, 10(69),
(4) Reffelmann, T et al, (2011), Is cardiovascular mortality related to the season of birth? Evidence from more than 6million cardiovascular deaths between 1992 and 2007, Journal of the American College of Cardiology, .57, 887–888.
(5) Kahn, H et al, (2009), Association of type1 diabetes with month of birth among U.S. youth: The SEARCH for diabetes in youth study, Diabetes Care 32, 2010–2015.
(6) Vaiserman, A, et al., (2009), Seasonality of birth in adult type 2 diabetic patients in three Ukrainian regions, Diabetologia, 52, 2665–2667.
(7) Flouris, A, et al, (2009), Effect of seasonal programming on fetal development and longevity: Links with environmental temperature, American Journal of Human Biology, 21(2), 214-216.
(8) Vicenzo, A, et al, (2009), Season of birth, gender, and social-cultural effects on sleep timing preferences in humans, Sleep, 32(3),
(9) Lorenzo, T. et al, (2012), Season of birth and handedness in young adults, Laterality; Asymmetries of brain, body and cognition, 17(5), 596-601.


Dr. Sadeghi & Dr. Sami
Dr. Habib Sadeghi D.O., is the co-founder of Be Hive of Healing, an integrative health center based in Los Angeles. With more than 15 years of direct patient care, he provides a comprehensive knowledge of revolutionary healing protocols in integrative, osteopathic, anthroposophical, environmental, and family medicine, as well as clinical pharmacology. Through a unique and individualized approach to healthcare that includes evidence-based, Western medical interventions and intuitive Eastern healing modalities, Dr. Sadeghi has been able to achieve astounding results in patient cases that were otherwise deemed hopeless by traditional medicine. Read biography 
Dr. Shahrzad (Sherry) Sami is a dual specialist in pediatric dentistry and orthodontics. She has served as a clinical instructor at the University of California Los Angeles, as part of both the pediatric medicine and dentistry programs, becoming one of the creators of the Children Health Advocacy Training (CHAT) curriculum. Collaborating with pediatricians, Dr. Sami designed one of the few residency training programs that incorporates a whole body approach that includes aspects such as breastfeeding, nutrition and child development. Her practice is based on total body wellness, a philosophy that recognizes the synergistic connection our emotions play in our physical condition. It also emphasizes the correlation of a healthy mouth, jaw and airways with a vibrant, energetic body. Read biography
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