Lifetime income is less variable than annual household income, since the latter reflects transitory shocks to wages, family status, and employment. The paper presents an aggregate time-series analysis of unemployment and infant health that improves on previous work in several ways. First, the data is monthly as opposed to annual and pertains to New York City from January, 1970 to December, 1986. Second, a structural production function is estimated in which the race-specific percentage of low-birthweight births is the health outcome. Because we are able to control for the race-specific percentage of women who begin care in the first trimester as well as the percentage of births to unmarried mothers, the unemployment rate as a proxy for maternal stress enters the production function as one among a set of well-defined health Inputs. Third, because a pregnancy is limited to at most ten months, we can specify a lag length with confidence. Fourth. the data is tested for stationarity and the production function is estimated in levels as well as in deviations from trend. We find no cyclical variation in the percentage of low-birthweight births. The results are insensitive to changes in lag length. the omission of relevant inputs, and the functional form of the coefficients on the distributed lag.