_1 Miscarriage 08/2015
_2 Live birth  06/2014
_3 Abortion    02/2012
_4 Live birth  06/2009

_1 Live birth  06/2014
_2 Live birth  06/2009

_1 Miscarriage 08/2015  _1 Live birth  06/2014
_2 Live birth  06/2014  _2 Live birth  06/2009
_3 Abortion    02/2012  empty
_4 Live birth  06/2009  empty

use "NPIR60FL.DTA", clear

rename *_0* *_*

* fix for pidx97 pord97 s220c s220f s225c s225f s226c s226f and sprego

replace s209 = 0 if s209 == .
capture gen tot_pregs = v201 + s209
capture gen flipmax = int(tot_pregs/2)
capture gen tempvar = .

* reverse values of some variables to fix errors in the data file
capture program drop flip_var
program flip_var
syntax anything if
replace tempvar = `1'_`2' `if'
replace `1'_`2' = `1'_`3' `if'
replace `1'_`3' = tempvar `if'
end

local vlist pidx97 pord97 s220c s220f s225c s225f s226c s226f sprego
* maximum of 15 entries used in pregnancy history, minimum of 2 as no need to flip when only 1 pregnancy
forvalues p = 2/15 { 
	forvalues i = 1/7 {
		local j = `p'-`i'+1
		if `j' > `i' {
			foreach v of local vlist {
				flip_var `v' `i' `j' if tot_pregs == `p'
				di "flip_var `v' `i' `j' if tot_pregs == `p'"
			}
		}
	}
}
drop flipmax tempvar
* end of fix for s220c s220f s225c s225f s226c s226f and sprego

* keep just the variables needed
keep caseid v001 v002 v003 v005 v008 v011 v013 v017 v018 v019 v021 v022 v023 v024 v025 v201 tot_pregs b3_1  /// 
  pidx97_* pord97_* bidx97_* s215_* s216_* s217_* s219_* s220m_* s220y_* s220c_* s220f_* s220a_* s221_* ///
  s226m_* s226y_* s226c_* s226f_* s227_* s228_* s229_* sprego_* 

* set up list for reshape
local varlist pidx97_ pord97_ bidx97_ s215_ s216_ s217_ s219_ s220m_ s220y_ s220c_ s220f_ ///
  s220a_ s221_ s226m_ s226y_ s226c_ s226f_ s227_ s228_ s229_ sprego_

* capture the variable labels
foreach v of local varlist { 
	local l`v' : variable label `v'1
}

* reshape into long format file of pregnancies
reshape long `varlist', i(caseid) j(p)

* copy the variable labels back to the variables
foreach v of local varlist {
	label variable `v' `"`l`v''"'
}

* drop the empty pregnancy records
drop if pidx97_==. 

* rename the variables 
rename pidx97_ pidx97
rename pord97_ pord97
rename s*_ s*

* create cmc date of pregnancy for all pregnancies
gen cmc_preg = s220c
replace cmc_preg = s226c if cmc_preg == .

* compute the weight
gen wt=v005/1000000

* tabulate outcome for births and stillbirths
tab sprego [iw=wt] if v008 - cmc_preg < 60 & sprego <= 2

* tabulate outcome dropping stillbirth twin of live birth to match calendar approach
tab sprego [iw=wt] if v008 - cmc_preg < 60 & s226c != b3_1 & sprego <= 2