To the Editor,
The review by Bhutta et al (2005) of community-based interventions
targeting perinatal and neonatal health in developed countries provides a
major contribution to increase awareness of researchers and policy makers
about needs in this field. However, while we recognize that the authors
focused mainly on evidence from randomized clinical trials (RCTs), we
would like to point out that the discussion in this review may have
benefited by incorporating several studies conducted by researchers in the
health economics field that measure the impact of prenatal care on at-
birth and neonatal health. While these observational studies are
suboptimal to RCTs in establishing causality, the statistical models
applied in these studies and the subject samples used, potentially provide
estimates of the “effectiveness” (real world effect) of prenatal care,
rather than estimates of “efficacy” usually obtained from RCTs. These
studies (e.g. Rosenzweig and Schultz (1983), Corman et al (1987), Grossman
and Joyce (1990), Frank et al (1992), Joyce (1994), Warner (1995)) have
evaluated the impact of several measures of the quantity of prenatal care,
including delay in initiating prenatal care, number of prenatal care
visits, first semester initiation of prenatal care, and adequacy of
prenatal care (Kessner index) on various infant health outcomes, including
birth weight, gestational age, and intrauterine growth retardation.
The discussion in the supplement seemed to focus specifically on the
optimal number of prenatal care visits. There is some research evidence,
however, of a difference in the magnitude of the impact of delay in
initiating prenatal care and of number of prenatal visits on infant health
outcomes, with the former demonstrating a larger effect (e.g. Warner
(1995)). Further, as a substantial proportion of women receive no
prenatal care in developing communities, it seems of equal importance to
discuss the impacts of delay in seeking prenatal care, compared to number
of visits, as decreasing delay in seeking prenatal care may be a much
easier target to achieve, as a first step, for health policies and
programs in developing communities, rather than implementing and ensuring
access to a pre-packaged prenatal care program.
While these studies are based on US samples, they provide useful
results for achievable effectiveness of prenatal care in developing
settings where health care technology usually lags far behind that of more
developed communities. Finally, the authors mention that they could not
cite a single source of objective evidence of the marginal impact of
prenatal care on neonatal mortality (p 533). Corman et al (1987) provided
estimates of proportion of births with prenatal care initiated in first
trimester of pregnancy on neonatal mortality.
References:
Bhutta ZA, Darmstadt GL, Hasan BS, Haws RA. Community-Based
Interventions for Improving Perinatal and Neonatal Health Outcomes in
Developing Countries: A Review of the Evidence. Pediatrics. 2005;115:519-
617.
Corman H, Joyce TJ, Grossman M. Birth Outcome Production Function in
the United States. The Journal of Human Resources. 1987;22:339-360.
Frank RG, Strobino DM, Salkever DS, Jackson CA. Updated Estimates of
the Impact of Prenatal Care on Birthweight Outcomes by Race. The Journal
of Human Resources. 1992;27:629-642.
Grossman M, Joyce TJ. Unobservables, Pregnancy Resolutions, and Birth
Weight Production Functions in New York City. The Journal of Political
Economy. 1990;98:983-1007.
Joyce TJ. Self-Selection, Prenatal Care, and Birthweight among
Blacks, Whites, and Hispanics in New York City. The Journal of Human
Resources, 1994;29:762-794.
Rosenzweig MR, Schultz TP. Estimating a Household Production
Function: Heterogeneity, the Demand for Health Inputs, and Their Effects
on Birth Weight. The Journal of Political Economy. 1983;91:723-746.
Warner GL. Prenatal Care Demand and Birthweight Production of Black
Mothers. The American Economic Review. 1995;85:132-137.
eLetters: ![[Read eLetters]](/icons/misc/sectionDOWN.gif){kind=icon}
