show Abstracthide AbstractThe total RNA was extracted, and a small RNA library was subsequently generated and sequenced on the Illumina platform. There were 4022 unique miRNAs found during the pregnancy, with 15 of those lacking sequences in the database and 32,299 having sequences already. From the beginning of pregnancy until the 18th day, 25 of these miRNAs showed a substantial shift in expression levels in the maternal blood, with a change more than 2 logs.