Specimens analyzed for this study were collected under three separate IRB approved studies. Plasma was extracted from whole blood specimens from pregnant subjects collected under protocol SQNM-T21-106 (Compass IRB 00462). Subjects provided written informed consent and were 18 years of age or older and pregnant carrying a singleton fetus of 10 to 26 weeks gestational age inclusive. Plasma was extracted from whole blood specimens from non-pregnant female subjects collected under protocol SQNM-RND-103 (Aspire IRB T21106). Subjects provided written informed consent and were normal healthy volunteers 18 years of age or older confirmed not to be pregnant. Peripheral blood mononucleated cells (PBMCs or buffy coat) were extracted from whole blood specimens from pregnant subjects collected under protocol 1128724 (Western IRB 20111833). Placental tissue was collected from subjects under the same protocol (1128724). Subjects provided written informed consent and donated the whole blood and aborted material as an anatomical gift for the purposes of education, research, or for the advancement of medical science.