“…Most pertained to a specific contraceptive method (implants: 20, IUDs: 12, combined OCPs: 10, progestin-only and combined injectables: 4, vaginal ring: 2), while 13 addressed multiple methods and 10 were not method-specific. While bleeding changes may have been inconsistently defined (by researchers and study participants) across studies, spotting, unpredictable, frequent or irregular bleeding were defined as negative side effects in 42 studies [ 43 , 48 – 50 , 52 – 54 , 72 , 75 , 77 , 78 , 81 , 82 , 84 , 86 , 88 – 92 , 94 , 97 , 98 , 100 , 102 , 105 , 106 , 108 – 111 , 116 – 119 , 122 , 123 , 127 – 129 , 132 ], 22 studies noted that heavy or prolonged bleeding were poorly tolerated [ 49 , 53 , 54 , 77 , 83 , 84 , 91 , 92 , 98 , 101 , 103 , 104 , 106 , 110 , 111 , 113 – 115 , 123 , 129 , 131 ], and 22 studies found contraceptive-induced amenorrhea to be problematic [ 44 , 48 – 50 , 76 , 78 , 79 , 84 , 86 , 90 , …”