Peter, Thanx for rapid feedback, but I'm not sure if I agree with your reasoning to remove the "abortion factor" - mainly because whereas only a minority of women ACTUALLY come for their 1st ANC (booking) visit in the first trimester (and that minority is small in Nigeria), the POLICY and acknowledged "Good quality ANC care" means that they SHOULD come in the first trimester. My understanding of policy in this context is that government thus regard pregnant women during the last part of the first trimester as part of their target group for antenatal care.
And the denominator for ANC coverage should ideally be identical to the full target group - if women in practice delay before seeking ANC care, then I would still argue that it's better to use the full target group in the denominator AND instead reduce the short/medium term target to e.g. 90% instead of 95% (or 95% instead of 100%, etc). For South Africa we have used a factor of 1.15 (but NOTE that this estimated factor is also based on my non-specialist understanding - so quite possibly wrong). Also note that in SA, taking out the abortion group from the factor will for most provinces/districts result in Antenatal coverage tipping over 100% (we know from e.g. the Demography and Health Survey that ANC coverage on average is ~95%). Whether that is caused by errors in the antenatal routine data, errors in overall population estimates, the taking out of the "abortion factor" - or a combination of the three - are of course debatable. So yes, it would be great if somebody with more in-depth understanding of antenatal/pregnancy "pathways" would chip in.... Regards calle > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of pbarron > Sent: 08 February 2008 03:44 PM > To: 'DHIS 1.4'; [EMAIL PROTECTED]; 'DHIS_Users' > Cc: 'Debbie Bradshaw' > Subject: Re: [Dhis14] How to estimate potential ANC clients > based on thenumberof children under 1 year from a Census > > Dear Calle > > Thanks for putting this out. I am not an obstetrician but a > pragmatic public health jack of all trades pratitioner. I > think that the 1.23 factor is high: > > In practice very few women in a developing country public > sector will book before 12-16 weeks by which time most (I > would say 95%+) abortions will have already occurred. > Therefore this abortion factor should be taken out of the > denominator estimation. > > So I would say if 1000 women at 16 weeks are estimated to > need antenatal care then they will deliver 1000 (plus say 20 > for twins - 30 for > stillbirths) = 990 babies. > > If you have estimate of IMR of 100 then an estimated 75 will > die by 6 months of age. This will leave a midyear census of > under one year olds of (990-75)= 915. > > To get this figure back to 990 (the estimated number of women > who need antenatal care) then you have to multiply the 915 by > a factor of (990/915) 1.082. > > In addition this is probably an over-estimation of the real > situation as the census figures are based on extrapolations > over time. As fertility is generally dropping over time these > extrapolations probably use fertility rates that are higher > than the real figure. > > SO in short I think that 1.23 is far too high and results in > a large under-estimate of the antenatal coverage. > > I hope that this will result in a participation of a number > of epidemiologists, managers and other interested parties so > that we can get a more consensus based result. > > Regards > > Peter > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Calle Hedberg > Sent: 08 February 2008 02:41 > To: 'DHIS 1.4'; [EMAIL PROTECTED]; 'DHIS_Users' > Subject: [Dhis14] How to estimate potential ANC clients based > on the numberof children under 1 year from a Census > > Terpase, > > ******************************* > On 08/02/2008, Aluka Terpase <[EMAIL PROTECTED]> wrote: > Hi Calle > > I was going through some of the indicators and was unable to > explain how we arrived at the denominator"SUM([Female under 1 > year]) + SUM([Male under 1 > year]) * 1.23" for calculating ANC coverage. > > Could you throw more light" > ******************************* > > I am echoing this reply to the various DHIS discussion lists, > because I think it has wider interest (estimating potential > ANC clients accurately are a challenge for all countries, not > only Nigeria). > > Explanation: > > If you draw a timeline from "conception" to "census taking of > children under > 1 year" (i.e. the children under 1 will on average be around > 6 months during the census), it is a bit easier to determine > the factor to multiply with the number of children under 1 > year as per the census in order to estimate the number of > "Potential ANC clients". > > Just note that we are making two assumptions: > > (1) All women who has been pregnant for 10 weeks or more > should be aware that they are pregnant, and they should > receive ANC care (in most countries, the policy is to > encourage the first ANC visit in the first trimester, which > is before 13 weeks). > > (2) We assumed that about 25% of all pregnancies end up with > a spontaneous (or induced) abortion between 0-28 weeks > gestation - that estimate was based on similar estimates from > South Africa (abortion rates in wealthy countries are usually > about half of that). AND we assumed that around 1/3 of those > (~7-8%) occur between 10-28 weeks (i.e. those women have then > become potential ANC clients BEFORE the pregnancy ends, for > whatever reason). > > So you can set up the following timeline from "day 0" > (conception) via 10 weeks (woman aware of pregnancy) and 28 > weeks (normally viable foetus, i.e. > 28 weeks divides spontaneous abortions from still births) and 38 weeks > (delivery) to 6 months after delivery (average age for > children under 1 year at time of census): > > Day 0: 1,000 women conceive > 10 weeks: ~ 830 of them are still pregnant > 28 weeks: ~ 750 of them are still pregnant > 38 weeks: ~ 760 (10 twins) babies are born, with ~30 still > born and 730 live born Neonatal period (0-28 days): Neonatal > death rate is 53/1,000 live births, so ~40 die. > 29 days - 6 months: infant mortality of ~22/1,000 live > births, so another 15 die. > 6 months after delivery: 675 are still alive to be counted in census > > Total infant mortality for Nigeria (Unicef, 2005) is > 100/1,000 live born, but 53 of them die during the neonatal > period and I estimate another 22 from > 28 days to 6 months - which means that the last 25 will die > between 6 months and 1 year. > > So the census figure that we are using as our basis will be > 675. If you multiply that number with 1.23 (i.e. add 23%), > you see that you arrive at ~830 - which is the estimated > number of pregnant women who we regard as "potential ANC > clients" (they SHOULD receive antenatal care). > > The various rates and assumptions are not 100% correct, of > course - so anybody with better data/ideas are encouraged to > revise them and improve the accuracy of the estimate. > > Hope this helps. > > Regards > calle > > > _______________________________________________ > Dhis14 mailing list > [EMAIL PROTECTED] > http://www.hisp.info/mailman/listinfo/dhis14 > > _______________________________________________ > Dhis14 mailing list > [EMAIL PROTECTED] > http://www.hisp.info/mailman/listinfo/dhis14 > _______________________________________________ Dhis-users mailing list [email protected] http://www.hisp.info/mailman/listinfo/dhis-users
