Birth

Birthweight, the length of a pregnancy and survival through the first year are recorded for nearly every birth in the country, which makes them the earliest outcomes that can be set against the place where a mother lived. Three chapters of this part ask how those early outcomes differ with place. A fourth asks a separate question, how many children are born, and its counts say nothing about how healthy the births were. Every chapter compares counties or states and describes groups of births. None describes a particular mother or says why her baby weighed what it did, and the county comparisons cover the counties that CDC WONDER names individually, not the smaller counties it pools.

Chapter 2.1, Birthweight and preterm birth finds that the shares of babies born at low birthweight and preterm are higher where a county's neighborhoods are more deprived. The rate of low birthweight for non-Hispanic Black mothers is higher than the rate for non-Hispanic white mothers in every quartile of county deprivation, so the gap between the two groups is not a difference between richer and poorer counties alone.

Chapter 2.2, Infant mortality follows births through the first year and finds that, among the large counties that publish a death count in every year, the infant mortality rate rises with county deprivation. The files carry no cause of death and no birthweight, so the chapter cannot say how the conditions described in the first chapter relate to the deaths described in the second. It can say that both are more common in more deprived counties.

Chapter 2.3, Smoking in pregnancy moves to a condition before birth. In the large counties with a usable count, the share of births to mothers who reported smoking fell from 2018 to 2024, and within a state the share is lower where county income is higher. Whether that slope differs between states depends on how counties are weighted and on the scale of the comparison.

Chapter 2.4, Where births are falling counts births instead of describing them. Births in the counties that CDC WONDER identifies fell from 2018 to 2024, the losses did not rise in steps with county deprivation, and births to mothers in their late thirties and early forties rose while births to mothers under thirty fell. A birth rate would divide births by the women who could have had them, and the staged files hold no county counts of women by age, so the chapter reports counts and shares and no rates.