Summer (now) may be the ideal time to conceive

Setting babies up for lifetime healthy circadian rhythms

Sunlight exposure in early pregnancy may improve outcomes at the end of pregnancy, reduce the risk of preterm birth, and support a more mentally stable postpartum recovery while also supporting the entrainment of baby’s circadian rhythms and developmental outcomes from an earlier age.

Happy solstice! Happy winter/summer, depending on where you are!

Are you a summer baby or a winter baby? And if given the choice, which season would you prefer to have your next baby?

Birthday is actually associated with melatonin levels in the first couple of months of life… suggesting that even though human fertility isn’t completely tied to the seasons the way animal life is… Season does still affect us and our babies at a deep level!

With circadian health being established in the womb and babyhood, the perinatal (peri = around, natal = birth) window is the most opportune time to experience the magic of healthy light habits.

Ideally, and independent of season, circadian stabilization would be part of every family’s preconception work.

Work with me 1-1 for preconception:

This is because the circadian rhythm supports healthy processes in the reproductive systems of both women and men, setting the stage for the healthiest possible conception.

As per Tamura et al:

Melatonin plays an essential role in the pathogenesis of many reproductive processes. Human preovulatory follicular fluid (FF) contains higher concentrations of melatonin than does plasma, and melatonin receptors are present in ovarian granulosa cells (GC). Melatonin has been shown to have direct effects on ovarian function. Reactive oxygen species and apoptosis are involved in a number of reproductive events including folliculogenesis, follicular atresia, ovulation, oocyte maturation, and corpus luteum (CL) formation. Melatonin and its metabolites are powerful antioxidants; the primitive and primary function of melatonin may be its actions as a receptor-independent free radical scavenger and a broad-spectrum antioxidant. A large amount of scientific evidence supports a local role of melatonin in the human reproductive processes.

Source: Tamura, H., Nakamura, Y., Korkmaz, A., Manchester, L. C., Tan, D. X., Sugino, N., & Reiter, R. J. (2009). Melatonin and the ovary: physiological and pathophysiological implications. Fertility and sterility, 92(1), 328–343. https://doi.org/10.1016/j.fertnstert.2008.05.016

And from Green at al:

The last several decades have been characterized by the widespread usage of digital devices, especially smartphones. At the same time, there have been reports of both decline in sleep duration and quality and male fertility decline… The results of this study support a link between evening and post-bedtime exposure to light-emitting digital media screens and sperm quality.

Source: Green, A., Barak, S., Shine, L., Kahane, A., & Dagan, Y. (2020). Exposure by males to light emitted from media devices at night is linked with decline of sperm quality and correlated with sleep quality measures. Chronobiology international, 37(3), 414–424. https://doi.org/10.1080/07420528.2020.1727918

While healthy babies can be conceived and born at any time of the year, from research and anecdotal perspective, now may be the best time to invite a new baby into your life through conscious conception.

If you are in winter, it’s time to rest & nourish yourself in preparation for the return of the sunlight in Spring.

If you are in summer and have been nourishing yourself well for the past 6 months, it’s the perfect time to start trying to conceive. Or if you haven’t been, it’s a great time to maximize sunlight and nutrition so you can try to conceive in the fall before the sunlight window closes.

I support families through the entire birthing year, offering preconception, pregnancy, birth planning, and postpartum support through a circadian and quantum lens. As a paid subscriber, you can get text-based Q&A to support your journey in the Brighter Days, Darker Nights paid subscriber chat. For a more personal level of support, I offer 1-1 virtual doula visits.

Research from 2021 suggests there may be many benefits to getting higher sunlight exposure in the first trimester:

Sunlight is a component of the natural environment that is necessary for human health. Vitamin D production, nitric oxide production, and activity of the immune system are all influenced directly by sunlight with implications for disease manifestation. These pathways are central to the establishment and maintenance of pregnancy, with the early pregnancy state establishing risk for later outcomes. However, sun exposure in pregnancy remains mainly incidental and unconsidered. Although there have been relatively few studies, a systematic review of sun exposure and pregnancy outcomes found associations with fetal growth restriction, blood pressure, and preterm birth rates, with higher first trimester sunlight correlating with higher fetal birth weights and less hypertensive complications in the third trimester.

Source: Megaw, L., Clemens, T., Daras, K., Weller, R. B., Dibben, C., & Stock, S. J. (2021). Higher Sun Exposure in the First Trimester Is Associated With Reduced Preterm Birth; A Scottish Population Cohort Study Using Linked Maternity and Meteorological Records. Frontiers in reproductive health, 3, 674245. https://doi.org/10.3389/frph.2021.674245

The other benefit of conceiving in the Summer or Fall is you will have your baby in the Spring or Summer. This may give your baby higher melatonin levels after birth (as shared earlier in this post), and also may offer protection for your own mental health as a mother since your third trimester and birth will also be in a sunny season. As per Goyal et al:

When days were shortening (August to first 4 days of November) in late third trimester, depressive symptom scores were highest (35%) and continued to be higher at each postpartum assessment compared to other day length categories. Implications for clinical practice include increased vigilance for depressive symptoms, particularly if late pregnancy and birth occurs during the 3 months around the Autumn equinox when day length is shortening. Strategies that increase light exposure in late pregnancy and postpartum should also be considered.

Source: Goyal, D., Gay, C., Torres, R., & Lee, K. (2018). Shortening day length: a potential risk factor for perinatal depression. Journal of behavioral medicine, 41(5), 690–702. https://doi.org/10.1007/s10865-018-9971-2

With all of this in mind, a natural question might arise about when to start bringing baby to the sunlight after they are born.

1-1 Postpartum Planning

When to start exposing baby to sunlight will always be a personal decision, but having your baby in a season where this is easier may also benefit their health. The data from many sources suggest the first 6 months of life to be one of the most critical.

Analysis by Dustmann et al of data from over 600,000 school-aged children reports:

In terms of magnitude, 100 additional hours of sunshine in this time period, which is equivalent to the increased sun intensity from a two-and-a-half-week-long holiday in winter to a destination where sunshine is similar to that in summer, reduce the risk of being overweight at age six by 1.1 percent, the risk of obesity by 2.6 percent, and the risk of severe obesity by 6 percent. Sun intensity beyond the first six months of life, in contrast, has no discernible impact on subsequent adiposity. Sun intensity during the last trimester of pregnancy also reduces the risk of adiposity at age six, although this effect tends to be smaller in magnitude than during the first six months of life.

Source: Dustmann, C., Sandner, M. and Schönberg, U. (2022). The effects of sun intensity during pregnancy and in the first 12 months of life on childhood obesity. Journal of Human Resources, 0920-11159R1. https://doi.org/10.3368/jhr.0920-11159R1

While Orjuela-Grimm et al report:

Contrary to expectations, we found a protective effect of sun exposure for development of retinoblastoma specific to those whose mothers did not cover their child's eyes and thus were not attempting to decrease UV exposure. The protective effect of sun exposure appears stronger in the first 6 months of life, which coincides with timing of disease initiation for both unilateral and bilateral disease. There is a marked protective effect in the second year of life, which can contribute to disease initiation in unilateral disease, but suggests a different role contributing to the second hit in bilateral disease. The protective effect of sun exposure was restricted to children who did not wear coverings shielding their eyes during sun exposure in older ages, suggesting a potential role for sun exposure that can be obliterated with coverings that shield eyes. This may imply a beneficial effect from actual UV exposure.

Source: Orjuela-Grimm, M., Carreño, S. B., Liu, X., Ruiz, A., Medina, P., Ramirez Ortiz, M. A., Rendon, J. R., Molina, N. C. L., Pinilla, H., Hinojosa, D., Rodriguez, L., Connor, A. O., Rodriguez, F. M., Castañeda, M. V. P., & Cabrera-Muñoz, L. (2021). Sunlight exposure in infancy decreases risk of sporadic retinoblastoma, extent of intraocular disease. Cancer reports (Hoboken, N.J.), 4(6), e1409. https://doi.org/10.1002/cnr2.1409

And Huiping et al report:

As for motor development, we found that the infants exposed to sunlight 7–14 h/week had the best scores of infant motor development and the lowest cortisol among the groups. Thus, sunlight exposure for 7–14h/week, or 1–2 h per day, was critical for decreasing elevated cortisol levels and ameliorating delayed motor development in infants of mothers suffering from perinatal depression.

Source: Zhang, H., Liu, S., Si, Y., Zhang, S., Tian, Y., Liu, Y., Li, H., & Zhu, Z. (2019). Natural sunlight plus vitamin D supplementation ameliorate delayed early motor development in newborn infants from maternal perinatal depression. Journal of affective disorders, 257, 241–249. https://doi.org/10.1016/j.jad.2019.07.010

Thus, we have statistical evidence baby’s health can be improved by as little as 11 minutes of sunlight per day, but that 1-2 hours per day across the first 6 months of life makes an even stronger impact.

My Circadian Pregnancy, Birth, and Infancy Workshop is a great place to start if you want to learn how to set baby up for a lifetime of healthy circadian rhythms. Here’s where you can jump in if you are already a paid subscriber.

And if you haven’t joined as a paid subscriber yet, you can use this link to enjoy a discount for your first 12 months so you can enjoy the workshop on your own time: