My first son was born at week 42. 
My wife is now pregnant again.
I want to know what are the distribution of birth probability to
weeks, given the date of the first birth.
In other words, what is the correlation between the date of first and the
second birth-giving.
 
Thank you.

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Clarification of Question by sergv-ga on 13 Sep 2006 11:19 PDT

Thank you for all the replies,

I understand that there is now assurance or warranty in due date prediction.
But there must be some research made on statistical data that shows if
any repeatability exists at all and how strong is it.
Thank you.

This cannot be extrapolated from a sample of 1.

Maybe after her 10th child a prediction (of sorts) could be made.

Don't worry, the baby will come when it's ready.

http://answers.google.com/answers/threadview?id=110577

http://answers.google.com/answers/threadview?id=515106

Check out these previous questions on Google Answers.  The consensus
seems to be that there is suprisingly not data available on delivery
dates to figure out this type of odds.

From a sample of 1 (me), we recently had our second child at 39 weeks
6 days 23 hours after having our first child at 40 weeks 1 hour. (Our
first child came 1 hour before 40 weeks and our second child came 1
hour after 40 weeks.) There really is no way to predict though.
Congratulations, it will happen when it happens!

For those keeping score, I accidentally switched the data for first
and second in the previous comment.

Research_help, you know the exact hour of conception? You either need
to get out more or get out less.

My sister managed  - well, it just happened -  to have two children on
the same date in different years.  It never occurred to me to ask
about the dates of conception - if maybe there was something special
they celebrated each year, ca. nine months previous.

This reminds me that our doctor predicted that our second child would
be born a week early; she wasn't, she arrived a week late.

Bryan

Markvmd - who said anything about knowing the time of conception? One
child came 1 hour before her due date, 1 child came 1 hour after her
due date.  I assume from your comment you've never had children or
known anyone who was pregnant, because every pregnant woman is given a
due date.  A due date is the day that the doctor expects the baby to
be born based on an average term of 40 weeks.  The due date is based
on several factors such as last period, assumed date of conception,
cycle, ultrasound measurements.