| Pregnancy duration [message #9443] |
Tue, 29 March 2016 07:06  |
SARAMBE
Messages: 5
Registered: March 2016
Location: Benin
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Member |
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Hi,
I am using Burkina Faso's 2010 DHS data.
I need pregnacy duaration for every child.
I don't know how to get it.
Thank you for your help.
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| Re: Pregnancy duration [message #9465 is a reply to message #9443] |
Wed, 30 March 2016 08:45  |
Liz-DHS
Messages: 1516
Registered: February 2013
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Senior Member |
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Dear User,
A response from Dr. Tom Pullum:
Quote:
If by "pregnancy duration" you mean the length of gestation for each birth, typically nine months, DHS does not collect that information. If you mean the estimated month of pregnancy for women who are currently pregnant, that's v214 in the IR file (BFIR43). If you mean something else, please clarify.
Thank you!
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| Re: Pregnancy duration [message #9500 is a reply to message #9497] |
Tue, 05 April 2016 10:50 |
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user-rhs
Messages: 132
Registered: December 2013
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Senior Member |
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Hi Aboubacar,
There's a variable called vcal_1 that stores information on births, pregnancies and contraceptive use during at least 5 years prior to interview. From the DHS recode manual:
Quote:
The calendar of events representing the 5+ years prior to the date of interview. The calendar is split into 9 records, representing each of the 9 columns. Each of the 9 columns contains a single character for each month in the time period. The data are stored as single variables of 80 characters, allowing for up to 80 months to be represented in the calendar. The first character in each variable represents the most recent point in time, while the 80th character position represents data for January of the year in which the calendar started. The calendars are fixed at the 80th character position, such that the first few entries in the calendar represent points in time after the date of interview, and are consequently left blank.
Just a word of warning, though, that because it is a string variable, you will probably need some kind of loop or macro to generate the pregnancy duration variable for each pregnancy for each woman. The variable looks like this in the dataset:
There have been several threads on this discussion board on using the vcal variable that you should read to help you get a better understanding of using this variable. Consult the DHS Recode Manual for the coding scheme of this variable.
hth,
rhs
[Updated on: Tue, 05 April 2016 10:57] Report message to a moderator |
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| Re: Pregnancy duration [message #9502 is a reply to message #9495] |
Tue, 05 April 2016 13:24 |
Liz-DHS
Messages: 1516
Registered: February 2013
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Senior Member |
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Dear User-RHS,
A response from Dr. Tom Pullum:
Quote:
Even the durations given in the calendars would not be very useful. I think they will almost always be nine months for live births, and that's because, after a month of birth is given, the nine months before that are assigned to pregnancy. There should be variation for pregnancy terminations other than live births, but I would not have a lot of confidence in the stated durations.
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| Re: Pregnancy duration [message #9503 is a reply to message #9443] |
Tue, 05 April 2016 14:00 |
Trevor-DHS
Messages: 805
Registered: January 2013
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Senior Member |
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Here is a simple set of code for getting the duration of pregnancy for each birth in the calendar (with caveats noted below). This uses the IR file:
local callen = 80
* create separate variables for every month
forvalues i = 1/`callen' {
gen vcal1_`i' = substr(vcal_1,`i',1)
* Calculate duration of pregnancy if there is a birth in this month
gen vcalp_`i' = indexnot(substr(vcal_1,`i'+1,`callen'-`i'),"P") if substr(vcal_1,`i',1) == "B"
* Note that cases with duration 0 are truncated cases where we do not know the length of the pregnancy
}
* reshape the data file into variables for each month
reshape long vcal1_ vcalp_, i(caseid) j(i)
lab var vcalp_ "Duration of pregnancy"
lab def vcalp 0 "Unknown duration"
lab val vcalp_ vcalp
* Keep only the births
keep if vcal1_ == "B"
* CMC date of birth
gen cmc=v017+80-i
You would need to match this up with the births in the birth history, which you can do using the CMC date of birth.
Two issues, though:
1) This only gets the duration of pregnancy for births and their pregnancy that are completely within the calendar. Any pregnancy starting before the calendar will not have a duration.
2) I would not trust the duration of pregnancy from the calendar calculated this way. The calendar was not designed to collect accurate duration of pregnancy. It can only be calculated in months this way and is likely to be reported as 9 months in most cases.
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