Date calculation at 3 months interval or trimester dates

[Sharan]

Hi fellow SAS users, 

I seek your help. I have a date variable which is pregnancy start date as preg_start.  I would like to create 3 date vars: End of trimester 1, end of trimester 2 and end of trimester 3

I.e. I would like to calculate date at  the end  of each trimester.

Suppose my date is 1st jan 2005, I would like to have the output as follows:

Preg_start          end_trimester_1             end_trimester_2               end_trimester3

1JAN2005           31Mar2005                      30JUN2005                       30SEP2005

[PeterClemmensen]

How do you define end of trimester dates? In terms of days after Preg_Start? 

[Kurt_Bremser]

A pregnancy trimester is defined as 13 weeks or 91 days, so you simply add the number 91 three times (SAS dates are counts of days).

[PGStats]

If this is more than an exercise, I suggest that you refine your definition of "pregnancy start date" and "end of first/second/third trimester". A good place to start is the Wikipedia page on human Pregnancy.

[Ksharp]

data _null_;
x='01jan2005'd;
d1=intnx('qtr',x,1,'s')-1;
d2=intnx('qtr',x,2,'s')-1;
d3=intnx('qtr',x,3,'s')-1;

put (x d:) (= date9.);
run;