On 12/15/2015, we implemented the new national standard for calculating gestational age per NCHS that uses the Obstetric Estimate instead of the LMP-based calculation (National Vital Statistics Reports, Vol. 64, No.5, Gestational Age in Vital Statistics Data: Transitioning to the Obstetric Estimate. June 1, 2015).
The update was applied to previously-published PPOR data for birth cohort years 2008-2012. The new method has the effect of slightly lowering gestational ages.
The effect was small enough not to change rates, and total number of Feto-infant mortality changed by no more than 8.
Since 2008, there has been a sharp increase in Unknown race in Birth data, which had the predominant effect of lowering the number of White births. This effect has been seen nationwide and is associated with the use of the “2003 revision” of the birth certificate (introduced in GA in mid-2007). After consultation with NCHS, we implemented their imputation rule for Unknown race on 1/10/2017.
The effect of the imputation for Mother’s Race in Birth data, on White Feto-Infant Mortality Rate (FIMR), was that there was a decrease in White FIMR due to increase in total number of White Births in the denominator.
The correction is most pronounced in the 2008 birth cohort with a decrease in White FIMR of 0.4, but lessens in subsequent years with a White FIMR decrease of 0.3 in the 2014 birth cohort.
In 2010, there was known underreporting of infant deaths. This may have affected the FIMR for the 2010 and 2011 birth cohorts.
On 04/25/2018, the lower limit for inclusion of births and fetal deaths was lowered from 500 grams to 200 grams. This has the effect of including more fetal death and linked live birth/infant death records. Doing so is more representative of actual feto-infant mortality. Compared with previous figures, this change has the effect of changing the feto-infant mortality number and rate from 1,351 and 10.3 respectively in 2015, to 1,912 and 14.5 after the adjustment.
Also the cells that comprise Newborn Care were updated to include late neonatal deaths of 2,500+ grams (formerly part of Infant Care). Infant Care therefore now includes less events.
Content Version
04/25/2018