What if someone goes over their estimated due date?

Only 4% of babies arrive on their 'estimated guess date' and it's also frequently calculated incorrectly. Let's check yours...

The concept of an 'estimated due date' is very crude science, especially if all you have to go on is an LMP and scan (even an early scan can be inaccurate by up to 10 days). The most useful piece of information is a certain date of ovulation, but don't assume that this is the same date you had sex. Ovulation and subsequent conception can occur 0-5 days after sex because sperm is nurtured within the fallopian tubes. Once released, an egg survives for up to 24 hours unless fertilised. Some women might then ovulate once more. Try the calculators below, and discuss any discrepancy with your care provider...

Calculating EDD ~ in order of reliability:

  • Confident or confirmed ovulation date:- add on 266 days
  • The date you last had sex during your fertile window (high, soft, open cervix, stretchy & clear cervical mucus with increased desire!) - work out an EDD range by adding on 261 to 266 days (or 261 to 267 days if you think you ovulated twice)
  • If you're not sure about either of the dates above use this calculator and adjust your average cycle length

How about a 'due month+' instead?

Even with an accurate EDD, 'full term' is defined by the WHO as 37 to 42 weeks. Some babies are ready at 37 weeks, others need up to five more weeks to 'cook'. Despite the emotive language, neither examples are 'early / premature' or 'late / postmature / overdue'. Here's a rough, illustrative breakdown:


Less than 37 weeks = 5%
37+0 to 37+6 = 5%
38+0 to 38+6 = 10%
39+0 to 39+6 = 20%
40+0 to 40+6 = 30%
41+0 to 41+6 = 20%
42+0 plus = 10%

What about 'natural induction' methods? 

They just don't work, sorry! Any positive reports are pure coincidence and some methods are unwise (please don't use evening primrose oil or castor oil). Birth expert Dr Michel Odent states that anything used before the baby deciding when it's ready to be born isn't remotely 'natural', and questions the safety of evicting babies before they're ready.

I agree with him, but also understand the desire to meet your baby and the pressure that mums can be under. Yet personal and professional experience has repeatedly shown me that the stress and anxiety felt by, and unfairly put on someone to 'perform' at this stage does absolutely nothing for encouraging birth to begin. Ironically, if a baby is genuinely ready, a person driving themselves crazy trying to 'get things going' isn't providing the relaxed, calm environment required... Consider replacing your social media profile picture with this!


overdue hypnobirthing natural induction

So forget all about trying to encourage birth to begin. Pretend you're 35 weeks. Do some relaxation including hypnobirthing and fear release, clear any 'stuff' with a good cry, swimming, massage, reflexology etc - but with the sole goal of relaxing. When your baby is ready and you're happy and calm, it'll most likely happen.

pregnancy-massage