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 Subject: Repeatability of birth date Category: Health > Women's Health Asked by: sergv-ga List Price: \$10.00 Posted: 12 Sep 2006 08:43 PDT Expires: 19 Sep 2006 11:03 PDT Question ID: 764478
 ```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.``` 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.```
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 Subject: Re: Repeatability of birth date From: probonopublico-ga on 12 Sep 2006 09:00 PDT
 ```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.```
 Subject: Re: Repeatability of birth date From: research_help-ga on 12 Sep 2006 09:02 PDT
 ```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!```
 Subject: Re: Repeatability of birth date From: research_help-ga on 12 Sep 2006 09:04 PDT
 ```For those keeping score, I accidentally switched the data for first and second in the previous comment.```
 Subject: Re: Repeatability of birth date From: markvmd-ga on 12 Sep 2006 12:47 PDT
 ```Research_help, you know the exact hour of conception? You either need to get out more or get out less.```
 Subject: Re: Repeatability of birth date From: myoarin-ga on 12 Sep 2006 18:09 PDT
 ```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.```
 Subject: Re: Repeatability of birth date From: probonopublico-ga on 13 Sep 2006 02:35 PDT
 ```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```
 Subject: Re: Repeatability of birth date From: research_help-ga on 13 Sep 2006 06:39 PDT
 ```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.```