['To determine whether increased frequency of mutant alleles of the progesterone receptor gene (PGR) was associated with preterm birth in a population of Hispanic women.', 'Placental DNA from 64 patients who had preterm births and 54 control patients was genotyped for 4 progesterone receptor gene polymorphisms by polymerase chain reaction (PCR) restriction fragment length polymorphism. The chi(2) test and t test were used to calculate statistical significance. Linkage disequilibrium was calculated using the Linkage Disequilibrium Analyzer program.', 'The genotypic frequencies of the 4 polymorphisms were not significantly different between the study and control groups. In addition, there was complete linkage disequilibrium between V660L, H770H, and PROGINS polymorphisms, but not with +331G/A polymorphism.'] Are progesterone receptor gene polymorphisms associated with preterm birth in a Hispanic population?