Labour & due date

Does a full moon bring on labour?

Checked against the sources listed on this page. Not reviewed by a clinician. Last updated 5 November 2026. How we check.

Myth

No. Large studies of hundreds of thousands of births found no link between the lunar cycle and when babies are born.

We remember the busy full-moon night on the labour ward and forget the busy ordinary nights. That is classic confirmation bias.

References

  1. Arliss JM et al. The effect of the lunar cycle on frequency of births. American Journal of Obstetrics & Gynecology, 2005

Related weeks

Week 38

More labour & due date myths

Partly true

Is pregnancy really 9 months?

Roughly. It is 40 weeks (280 days) from the first day of your last period, which is about 9 months and 1 week. From conception it is about 38 weeks.

 Myth

Will my baby be born on the due date?

Unlikely. Only about 4% of babies arrive on their exact due date. Most are born within about two weeks either side.

 Myth

Can spicy food or pineapple bring on labour?

There’s no good evidence that spicy food or pineapple starts labour. Some small studies suggest eating dates late in pregnancy may help the cervix ripen.