['To examine whether dietary trans fatty acids (TFAs) were associated with fetal loss (no. of pregnancies - no. of live births). The basis of our inquiry derives from the facts that the PPAR-gamma receptor plays a pivotal role in placental function and that TFAs down-regulate PPAR-gamma gene mRNA expression.', 'Retrospective study comparing dietary data on TFAs and total calories from Block 98 quantitative food frequency questionnaire on 104 women with insulin data and reporting one or more pregnancies.', 'Twenty-five- to 30-year follow-up as young adults (age 39.5 +/- 4.5 years) of schoolgirls in the Princeton School cardiovascular risk study.', 'Former participants in school-based research program at ages 6-18 years (1973-78), screened as part of follow-up study (1998-2003).', 'Fetal loss.', 'By stepwise logistic regression, with fetal loss (>or=1 vs. 0) as the dependent variable and total calories, percent calories from TFAs (linear and squared terms), diabetes (yes/no), serum insulin, age, race, body mass index, leisure and work physical activity, and education as explanatory variables, percent calories from TFAs was positively, curvilinearly, independently associated with fetal loss. For each 1-unit increase in the squared term of percent calories from TFAs, the odds of having fetal loss versus no fetal loss increased 1.106 times (odds ratio = 1.106; 95% confidence interval 1.026-1.192).'] Is dietary trans fatty acid intake associated with increased fetal loss?