Neonatal and Infant Weight-Specific Mortality Rates

As recent studies have indicated, underreporting of neonatal deaths may occur when neonatal mortality rates are below 750 per 1,00zero live births in the five hundred-1,000 g birth-weight range (one-three). In a very current study, neonatal* and infant** weight-specific mortality rates for New Mexico were computed from that state’s very important statistics information. No vital underreporting was found.

New Mexico recorded eighty seven,724 births from 1974 through 1977. Of one,438 recorded infant deaths, one,364 (ninety five%) were matched with corresponding birth records. Accuracy of neonate and infant classifications within the New Mexico records was checked by comparing important statistics codes with a laptop calculation old at death (day, month, and year of birth were subtracted from day, month, and year of death (four)). In solely nine instances was age at death coded as neonatal when it ought to have been postneonatal, or vice versa. Tables 1 and 2 show the New Mexico rates and corrected neonatal mortality rates for Georgia, 1974-1976 (2), infant mortality rates for New York Town, 1968 (5), and neonatal and infant mortality rates for the United States, 1960 (six). To assess relative variations in rates for varied areas, 95p.c confidence intervals were created for each birth-weight class*** (7). *Less than twenty eight days of age **Less than one year old ***Although previous studies have reported weight-specific mortality rates in grams, New Mexico’s weights were reported in pounds and ounces; thus, the data here are given in both systems.

Neonatal mortality rates for New Mexico failed to differ statistically in any of the 5 weight-specific classes from the corresponding corrected rates for Georgia. Similarly, infant mortality rates for New Mexico didn’t differ statistically in the first four weight-specific classes from the corresponding rates for New York City. Within the over-250zero-g category, the infant mortality rate from New Mexico was statistically distinct from that of New York City. Although the difference was not massive, it absolutely was important because ninety% of the births occurred in this class. Within the unknown-weight category, New Mexico’s rate was statistically completely different from Georgia’s for neonates and from New York Town’s for infants. The whole neonatal mortality rate (information for all known and unknown birth weights combined) for New Mexico differed statistically from that for Georgia, and the full infant mortality rate for New Mexico differed statistically from that for New York City. This shows the consequences of the unknown category and of the differential composition of every birth-weight class on the whole mortality rate. For New York City, it could conjointly replicate the vi-year lag between the study in that town and the New Mexico study.

U.S. mortality rates for both neonates and infants in all weight-specific categories and totals were significantly higher for 1960 than were the corresponding rates from the later studies in New Mexico, Georgia, and New York Town, presumably because of improved standards of living, medical technology, and public health. Reported by RG Rogers, Population Research Center, University of Texas, Austin, Texas; MW Ammann, AA Ortiz, P Totkamachi, New Mexico Vital Statistics Bureau, Santa Fe, New Mexico.