A lunar influence on birth?

Phase of the moon, labor, and birth time correlations

Women have long associated menstrual and birth cycles with the moon, a pattern that may be breaking down under widespread circadian disruption.

We have evidence from historical writings about this, and can also compare datasets from before and after the widespread adoption of fluorescent and LED lights to validate these claims.

What I always say is healthy babies can be born anytime of the year, month, or day!

But are there trends?

Yes, and I do hypothesize that women coming back into circadian alignment with their local environments will see stronger patterns.

For example, looking at nearly every birth in New York City for 1961–1963 showed a 10% increase in births during the brighter half of the lunar cycle.

See: Menaker, Walter. “Lunar Periodicity with Reference to Live Births.” American Journal of Obstetrics and Gynecology 98, no. 7 (August 1967): 1002–4. https://doi.org/10.1016/0002-9378(67)90089-0.

But if you search modern literature, they always say there’s no scientific consensus.

The other question or end of this spectrum is if there is a lunar correlation to fertility, as conception time will obviously influence birth date.

Although current consensus likewise doesn’t support the idea of a lunar influence on conception, a similar 1960’s cohort did find a correlation with higher conception rates after the 3rd quarter of the moon.