For the serum N-glycosylation characteristics likely originating for a large part from IgG-Fab, IgM, and IgA (fucosylated diantennary N-glycans with sialylation; A2FS) (15, 26), we observed a decrease in bisection with trimester progression (A2FSB, βA2FSB = −0.56 ± 0.04) and a rapid return to pre-pregnancy levels at 6 weeks postpartum (βA2FSB = 1.11 ± 0.03).