Labour & due date

Will my baby be born on the due date?

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

Myth

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

A due date marks 40 weeks. Full term is 39 weeks 0 days to 40 weeks 6 days, and labour anywhere from 37 to 42 weeks is common. First babies tend to come a few days later than later babies.

References

  1. Tommy’s: Pregnancy due date calculator
  2. Royal Berkshire NHS Foundation Trust: Baby due dates
  3. Jukic AM et al. Length of human pregnancy and contributors to its natural variation. Human Reproduction, 2013

Related weeks

Week 39Week 40

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

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.

 Myth

Does a full moon bring on labour?

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