when are babies born relative to their due date?

[BellyBelly]

So many reasons due dates can be off.

* Date of last period incorrect or unknown
* Date of conception unknown - luteal phase varies
* Not every woman has a 28 day cycle and ovulates on day 14 which due dates are worked out on
* Ultrasounds are incorrect / are already inaccurate within a few days and are based on averages, not your baby. Especially later ultrasounds, when genes have taken over and your baby is more unique.
* Emotional issues/stress deferring labour (adrenaline counteracts oxytocin)
* Average gestation is not 40 weeks, its an estimate smack bang in the middle of what is classed as full term. 37/38 (depends who you ask)-42 weeks is full term.

Personally I think due dates should be calculated on 42 weeks. After that you ARE overdue and can discuss plans to move things along, IF the dates are correct, IF there are signs mum and bub are not healthy and IF mother feels that she is okay with it.

[Ambah]

My DS was 5 days early.
DD was 3 days early.

So there definitely seems to be a trend there.

My sister has 4, and they were all born after their EDD.

[Cyathea]

Personally I think due dates should be calculated on 42 weeks. After that you ARE overdue and can discuss plans to move things along, IF the dates are correct, IF there are signs mum and bub are not healthy and IF mother feels that she is okay with it.

Amen to that Kelly, I think it would solve a LOT of stress, I suggest it to everyone I know actually Not that anyone listens...

[MummyTummy]

Very interesting thread here....

My DS, my 1st was born on his EDD. My waters broke two days earlier though and although I was left alone as long as I could I had to be induced and then c/s. (Bub never engaged and just wasn't budging after 42 hours!) So, how does this get worked out in statistics?

I also believe the mind plays a big role in our births, afterall this has been going on since day dot, so before doctors and hospitals etc. That primitive part of our brain is still there and our instinct is to have optimum conditions to give birth in. That's why we get the strong nesting instinct too in the later weeks of pregnancy.

[Cyathea]

That's why we get the strong nesting instinct too in the later weeks of pregnancy.

And we are the ONLY species on earth that create a 'nest' to birth in, then walk off, and give birth elsewhere...how crazy is that??

(Homebirth all the way... That's what optimises my birthing hormones...)

[AnyDream]

I'd like to see a graph or some data showing when babies are born relative to the due date that the doctor assigned early on in the pregnancy.

See Figure 7.4 on page 83 of the following publication, which shows The distribution of births by gestational age in 1999 (most recent published).

From The AIHW publication Australia's babies, their health and wellbeing.

ETA - you could contact the AIHW library to find out whether this data has been cross-compared with other demographic information such as age of mother, different countries of origin etc (this info was collected at both of my baby's births in different states, I'm sure it's all fed up the chain statistically).

[brightstar79]

My DS was born right on my EDD and I was the midwives seemed very surprised when they asked when my EDD was! According to one of the doctors who I saw during delivery, they said "only 5% of babies actually arrive on their EDD". I have yet to confirm if this statistic is correct.

[satya]

I don't know where you can get those stats from but I remember that in the Belly Buddy group I was in about 50% went early & 50% went late (based on EDD). I don't remember anyone going on the due date, but I could be wrong.

Some of those who went late were 2nd or 3rd time mums and some of those who went early were first time mums so no trend there either. I was a first time mum and gave birth at 38/4.

[Jewel]

DS1 born at 39weeks.
DS2 born at 39week+2days.