Subgroup peak serum MPA and NET concentrations
Given that non-study progestins were detected in a large proportion of the women in the mITT group at 25W, and that several women had low quantifiable study progestins at 25W, we performed a PP analysis on a subgroup of the whole cohort to reduce these potential confounding effects on peak serum levels at 25W. In this PP1 analysis, we excluded all individuals that had quantifiable levels (> LLOQ) of any non-study progestin at 25W, as well as all those that missed their study progestin injection at 24W (as indicated in Methods). A total of 119 women (54 in the DMPA-IM arm and 65 in the NET-EN arm) were excluded in the subgroup PP1 analysis. When comparing the demographic characteristics of the women between arms for the PP1 subgroup, no significant differences were detected (In the DMPA-IM arm, the median concentration of MPA at 25W was 6.83 nM (2.64 ng/mL) (IQR 5.09–8.80 nM), while in the NET-EN arm the median concentration of NET at 25W was 13.3 nM (3.97 ng/mL) (IQR 9.28–18.5 nM) in the PP1 analysis (