The Biostatistics and Bioinformatics Branch (BBB) of the Division of Population Health Research (DiPHR) aims to develop broadly applicable biostatistical and computational methods and algorithms for designing and analyzing studies conducted in DiPHR and the Division of Intramural Research (DIR). Asthma is a common chronic disease, and some women experience exacerbation and worsening of their asthma during pregnancy while others improve. Patients with asthma may have a defect in regulatory T (Treg) cells, which favors further TH2-cell proliferation. Treg cells are integral to the process by which the immune system differentiates foreign antigens (pathogens, etc.) and self-antigens and, as such, they also play a key role in mediating pregnancy tolerance. This clinical research study aimed to increase understanding of factors that predict poor asthma control during pregnancy as well as add to improve knowledge of the basic immunology of pregnancy. The B-WELL-Mom Study, a multicenter prospective cohort study, aims to increase understanding of factors that predict poor asthma control during pregnancy, and that add to our knowledge of the basic immunology of pregnancy . This Task Order will provide for storage and maintenance of approximately 22,660 specimens collected in the B Well Mom study. This study investigates predictors of asthma control variability during pregnancy including demographic, biologic, genetic and environmental factors with particular interest in the role of maternal allergy. Pregnancy requires the immune system to tolerate the “not self” fetus and the clinical presentation of asthma including improvement or worsening will contribute to knowledge of the basic immunology of pregnancy. Women who get worse during pregnancy may represent a vulnerable subgroup with respect to environmental exposures, such as poor air quality, which can exacerbate asthma and may have an independent effect on poor pregnancy outcomes.