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Home » Topics » Mortality » Stillbirth calculation for Philippines
Stillbirth calculation for Philippines [message #25465] Tue, 25 October 2022 03:24 Go to next message
Mihir is currently offline  Mihir
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Registered: September 2022
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I am trying calculate stillbirth using calendar data following the given example-

https://www.dhsprogram.com/data/Calendar-Tutorial/index.cfm# example4

However, while calculating stillbirth for Philippines, I could not find the variable called vcal_1. Is there any way to calculate stillbirth without using the vcal_1 variable?? I guess there must be a solution as there are estimates in the report. Please help me out.
Re: Stillbirth calculation for Philippines [message #25495 is a reply to message #25465] Fri, 28 October 2022 12:56 Go to previous messageGo to next message
Janet-DHS is currently offline  Janet-DHS
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Registered: April 2022
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Following is a response from DHS staff member Tom Pullum:

You are probably asking about the 2017 survey. The survey did not include a calendar, but did include pregnancy history, and you can use that to identify stillbirths in the past five years. Open the IR file in Stata and enter "describe s21*_01". The variables are indexed for pregnancies 01 through 20. The variable for outcome (for pregnancy 01) is s211c_01, and stillbirths have code 2. Here is the label:

. label list S211C_01
S211C_01:
1 born alive
2 born dead
3 lost before full term

It is actually much easier to work with a pregnancy history than a calendar, and pregnancy histories are being added to DHS-8 surveys.
Re: Stillbirth calculation for Philippines [message #26271 is a reply to message #25495] Thu, 02 March 2023 01:43 Go to previous messageGo to next message
Shadrick Kayeye is currently offline  Shadrick Kayeye
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Registered: February 2023
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Hi @Janet,

I wanted to use the same approach to calculate stillbirth for Zambia using the 2018 ZDHS dataset, but I have struggled to locate the correct variables. I want to work with the pregnancy history. Kindly guide

Kind regards
Re: Stillbirth calculation for Philippines [message #26291 is a reply to message #26271] Fri, 03 March 2023 14:30 Go to previous messageGo to next message
Janet-DHS is currently offline  Janet-DHS
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Following is a response from DHS staff member, Tom Pullum:

This survey does not have a pregnancy history and it does not have any separate questions about stillbirths. The only way to get at stillbirths is with the calendar, specifically vcal_1. Stillbirths in the calendar are identified with 6+ months with "P", followed (chronologically) by "T". The calendar would have been used to calculate the perinatal mortality rate, which includes the number of stillbirths in the 60 months before the month of interview, but that's the only interval for which stillbirths are given.

We could provide Stata code to construct a variable which is the number of stillbirths each woman had in the past 60 months, but would that be useful to you? For the great majority of women it would be 0. Let us know.
Re: Stillbirth calculation for Philippines [message #26294 is a reply to message #26291] Sat, 04 March 2023 14:37 Go to previous messageGo to next message
Shadrick Kayeye is currently offline  Shadrick Kayeye
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Registered: February 2023
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Thank you so much for your feedback Janet. Yes, kindly help me with the Stata code to construct a variable. Additionally, in the reports and in my research proposal, I have defined stillbirths as fetal deaths in pregnancies of 7 months or more. Should I stick to that definition or I go by your suggestion of 6+ months?

I will also be grateful if could provide me with stata code to calculate the number of women aged 15-49 who were pregnant in the 5 years preceding the survey focusing on those with pregnancies of 7+ months duration. Excluding those that were pregnant during the survey. This help to define my sample size.
Re: Stillbirth calculation for Philippines [message #26325 is a reply to message #26294] Tue, 07 March 2023 16:14 Go to previous messageGo to next message
Janet-DHS is currently offline  Janet-DHS
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Following is a response from DHS staff member, Tom Pullum:

A sequence of 6+ months of P (for pregnancy) followed by T (for termination) is interpreted as a pregnancy of 7+ months of pregnancy. I know that's counter-intuitive but that's how DHS does it. But can you clarify which country and survey you are talking about? Philippines is in the subject line but the last survey you mentioned is Zambia 2018.
Re: Stillbirth calculation for Philippines [message #26330 is a reply to message #26325] Wed, 08 March 2023 00:29 Go to previous messageGo to next message
Shadrick Kayeye is currently offline  Shadrick Kayeye
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Registered: February 2023
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Thanks Janet.

Thanks for the clarification. The survey which I am requesting guidance for is for Zambia. I will greatly appreciate your guidance on the Stata code to construct a stillbirth variable for Zambia.

Regards
Shadrick
Re: Stillbirth calculation for Philippines [message #26337 is a reply to message #26330] Wed, 08 March 2023 16:44 Go to previous messageGo to next message
Janet-DHS is currently offline  Janet-DHS
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Registered: April 2022
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Please refer to Tom Pullum if you have any other questions he is the one responding to your questions.

Following is a response from DHS staff member, Tom Pullum:

In the Zambia 2018 survey, the only information about stillbirths seems to be in vcal_1. This covers the interval from the start of the calendar (see the questionnaire for that) to the month of interview. The interval can be more than 60 months. The strings that indicate a stillbirth can be left-censored, that is, some of the months of pregnancy may be before the first month of the calendar, so it may not be possible to determine the length of those pregnancies.

The Stata lines below will identify whether the woman had a stillbirth, to the extent that it can be determined. The crucial command is "regexm", one of Stata's "string" commands. It produces a variable that is either 0 or 1.

* Identify stillbirths in the calendar, using the Zambia 2018 DHS survey.
* In this survey, miscarriages, abortions, and stillbirths are not given separate codes.
* Pregnancies that did not end in a live birth have code "T" in the monthe of termination.
* Stillbirths are T preceded by 6+ months with P. The calendars is in vcal_1.

use "..ZMIR71FL.DTA" , clear

gen had_stillbirth=regexm(vcal_1,"TPPPPPP")
label define noyes 0 "No" 1 "Yes"
label values had_stillbirth noyes
tab had_stillbirth

list vcal_1 if had_stillbirth==1, table clean
Re: Stillbirth calculation for Philippines [message #26358 is a reply to message #26337] Mon, 13 March 2023 12:24 Go to previous messageGo to next message
Shadrick Kayeye is currently offline  Shadrick Kayeye
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Registered: February 2023
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Thank you so much Jane, this is very helpful.
Re: Stillbirth calculation for Philippines [message #26362 is a reply to message #26358] Mon, 13 March 2023 14:29 Go to previous messageGo to next message
Shadrick Kayeye is currently offline  Shadrick Kayeye
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Registered: February 2023
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Thank you Jane once again. Just a final inquiry, I have followed the steps above but I have failed to reproduce the number of stillbirths (119) recorded in the 2018 ZDHS report. I just wanted to find out if there is something that I have missed. I keep finding 141, instead of 119. Is there a step that I have missed?

Thank you
Re: Stillbirth calculation for Philippines [message #26395 is a reply to message #26362] Wed, 15 March 2023 14:03 Go to previous messageGo to next message
Janet-DHS is currently offline  Janet-DHS
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Registered: April 2022
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Following is a response from DHS staff member, Tom Pullum:

A note to other forum users--the question is now about Zambia even though the subject line says "Philippines".

Without going into the file myself, I can speculate that there are two possible reasons for the difference. The first is that the number of stillbirths in the report will be weighted (by v005). If your number is unweighted, it will differ. A second reason is that the code I gave is for all months in the calendar, not just the 60 months before the month of interview. You can reduce vcal_1 to just the 60 months before the interview, and that will give a smaller number. You should be able to reduce vcal_1 to just the last 60 months, with the name "vcal", with this line: "gen vcal=substr(vcal_1,v018,60)".

I hope you can get close to a match if you reduce vcal_1 to vcal and count the weighted number of stillbirths, but there may still be some discrepancy because of pregnancies of indeterminate length at the beginning (the right end) of the calendar.
Re: Stillbirth calculation for Philippines [message #26516 is a reply to message #26395] Tue, 28 March 2023 15:19 Go to previous messageGo to next message
Shadrick Kayeye is currently offline  Shadrick Kayeye
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Registered: February 2023
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@Jane.

Thank you so much for the feedback. I was offline for sometime.

One last inquiry! I wanted to find on out on how to calculate the Number of pregnancies of 7+ months' duration. I want to only keep the total pregnancies of 7+ months in last 5 years. The result of this calculation will form the total population sample for my study.

Kind regards
Shadrick
Re: Stillbirth calculation for Philippines [message #26544 is a reply to message #26516] Thu, 30 March 2023 15:51 Go to previous message
Janet-DHS is currently offline  Janet-DHS
Messages: 694
Registered: April 2022
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Following is a response from DHS staff member, Tom Pullum:

Again, this post is about a survey in Zambia rather the Philippines.

The following Stata lines count up the number of strings of the two types--B or T preceded by 6 or more P's. I do not include ambiguous strings that overlap the beginning of the calendar. The number of pregnancies you are looking for will be the sum of these two types.

use "...ZMIR71FL.DTA", clear

* for each woman, count up the number of strings of TPPPPPP or BPPPPPP in vcal_1

gen nT=0
gen nB=0
gen str7 compare="."

quietly forvalues lcol=1/74 {
replace compare=substr(vcal_1,`lcol',7)
replace nT=nT+regexm(compare,"TPPPPPP")
replace nB=nB+regexm(compare,"BPPPPPP")
}

drop compare
tab nB nT
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