Objective: The objective of this study was to examine risks of preterm births, quantify the explanatory power achieved by adding medical and obstetric risk factors to the models and to examine temporal changes in preterm birth due to changes in Medicaid eligibility and the establishment of a maternal-fetal medicine referral system.
Study Design:The study used data from the 2001 to 2005-linked Arkansas (AR) Medicaid claims and birth certificates of preterm and term singleton deliveries (N ¼ 89 459). Logistic regression modeled the association among gestational age, demographic characteristics and risk factors, pooled and separately by year.Result: Physiological risk factors were additive with demographic factors and explained more of the preterm birth p32 weeks than later preterm birth. Changing eligibility requirements for Medicaid recipients and increasing the financial threshold from 133 to 200% of federal poverty level had an impact on temporal changes. The proportion of births p32 weeks declined to 33%, from 3.0 to 2.0. However, later preterm births declined and then increased in the last year.Conclusion: Physiological conditions are strongly associated with early preterm birth. Maternal behaviors and other stressors are predictive of later preterm birth. Unmeasured effects of poverty continue to have a role in preterm birth. Further examination of the referral system is needed. Journal of Perinatology (2012) 32, 176-193; doi:10.1038/jp.2011; published online 18 August 2011 Keywords: preterm birth; Medicaid; maternal risk factors
IntroductionThere are three intertwining sets of factors that are responsible for higher rates of pregnancy complications, preterm and low birth weight births:1 demographic characteristics including age, ethnicity and parity 2 socioeconomic characteristics, as indicated by marital status, education level and low income levels, and 3 health status, including the presence of such diseases and conditions as hypertension, diabetes and kidney and pulmonary diseases. Although it is generally known that these conditions and diseases contribute to 'high risk,' distinguishing the extent to which each of these factors contribute to complications, and suboptimal pregnancy outcomes are difficult. 1 The comprehensive review of causes, consequences and prevention of preterm birth conducted by the National Academy of Sciences (NAS) in 2006, laid out a research agenda for elucidating the etiology and causal pathways for this complex syndrome.1 The National Academy of Sciences committee stressed the importance of examining the inter-relationships between the multiple risk factors, which include behavioral, social, demographic and physiological conditions. They note that currently the prevention of spontaneous preterm birth is not emphasized in prenatal care because of a widespread belief that the causes are primarily social rather than obstetric or medical.1 In addition, the committee advised that preterm birth be defined as a heterogeneous syndrome with multiple causal pathways and presentations. T...