1. The Effect of Intention and Desirability on Preterm Birth McKenzie Lutz 1, Felix Okah 1,3 Tami Calvez 2, Jarron Saint Onge 2, Teresa Orth 1 1 UMKC School of Medicine, 2 University of Kansas Medical Center, 3 Children’s Mercy Hospitals and Clinics Introduction  In the US, only 40-50% of all pregnancies are intended. (Orr et al., 2000)  Women who’s pregnancies are unintended or undesired are at higher risk of preterm birth. (Shah et al., 2011)  This study compares the rate of preterm birth in unintended and undesired pregnancies to intended and desired pregnancies, while adjusting for psychosocial factors. Methods  A literary search on Google Scholar for “pregnancy intention and preterm birth” showed that studies have been done to assess the effect of intention of pregnancy on preterm birth, however, most studies did not account for covariates that could cause preterm birth.  Retrospective cohort study of preterm birth risks by pregnancy intention and desirability.  Data was obtained on 408,657 pregnancies, from 2005 to 2009, in the linked Birth Certificate and Pregnancy Risk Assessment Monitoring System (PRAMS) survey database.  Preterm birth was defined as birth occurring before 37 complete weeks of gestation.  Covariates included age, race, education level, stress, family income, number of dependents, and partner support of birth control and the index pregnancy.  The data was analyzed by chi-square and multivariable logistic regression analysis. Results  Cohort comprised of 84% Intended + Desired pregnancies and 16% Unintended + Undesired pregnancies.  The Unintended + Undesired group had higher rates of low-education (<13y, 65% v 41%), minorities (59% v 39%), and stress (81% v 64%).  The overall rate of preterm birth was 9.0%  Unintended + Undesired pregnancies had higher rates of preterm birth, 11.2% v 8.6%, and a relative risk of 1.37 (95% CI 1.34, 1.41).  The woman's age, education level, race, stress (sum index), and number of dependents were significantly associated with preterm birth.  On multivariable logistic regression, the odds of a preterm birth were similar for both groups of pregnancies after adjusting for psychosocial and demographic variables; Intended + Desired = 1.01 (0.93, 1.10) v Unintended + Undesired 1.00 (reference). Conclusion  The Intended/Desired status of a pregnancy is associated with preterm birth.  Unintended+Undesired pregnancies have higher rates of preterm birth; however, those effects appear to be mediated through demographic and psychosocial factors, especially race and stress.  Intent/Desirability is a good screening question for pregnant women.  Limitations of this study include data consisting of self-reported behaviors, misclassification errors, and incomplete/missing data.  Those who report an Unintended+Undesired status of their pregnancy, especially black women, ought to be closely monitored for stressors that may contribute to preterm birth. References 1.Newton, Richard W.,"Psychosocial Stress in Pregnancy and Its Relation to the Onset of Premature Labour." Br Med J (1979): 411-3. 2. Orr, S. et al.. "Unintended Pregnancy and Preterm Birth." Paediatr Perinat Ep (2000) 14.4: 309-13. 3.Shah, Prakesh et al. “Intention to Become Pregnant and Low Birth Weight and Preterm Birth: A Systemic Review” Matern Child J (2011) 15:205-16.