A 12-month comparative clinical investigation of a levonorgestrel-releasing intracervical device situated in the uterine cavity or cervical canal

Implantable contraceptives (subdermal implants and hormonally impregnated intrauterine systems) versus other forms of reversible contraceptives: two systematic reviews to assess relative effectiveness, acceptability, tolerability and cost-effectiveness.

“…110 Six studies (20%) stated that they only included women with a regular menstrual cycle. 87,98,115,[120][121][122] Nearly all of the studies, for both the RCTs and the non-randomised prospective cohorts, were either comparisons of IUSs with different hormonal dosage release rates or of IUSs versus non-hormonal IUDs. The two exceptions were studies by Wang and colleagues 47 who compared the LNG-20 IUS with Norplant-2, and Sivin and colleagues 72 who investigated return to fertility after discontinuation of subdermal implants, IUSs or IUDs.…”

“…Of the remaining 17 trials, ten provided information on method of randomisation (see appendix 6). 43,47,73,85,87,98,99,101,106,114 Eight trials documented that allocation of contraceptive method was concealed to the investigator, 43,47,73,87,98,99,106,113 but in only three studies was assessment of outcomes blinded. 101,113,114 Women remained blind to allocated method in an additional two studies.…”

“…43,111 In 14 studies, the compared groups were treated identically in terms of measurement of outcomes. 43,47,73,87,[98][99][100]101,105,106,111,113,114,116 A description of the characteristics of women lost to follow-up or who withdrew from the study was not provided in any of the publications.…”

“…Twelve studies used life-table analysis to determine pregnancy and continuation rates. 43,47,73,87,98,99,101,106,108,111,113,114 It was possible to determine whether single or multiple decrement probabilities had been reported in nine of these studies and eight gave single decrement probabilities.…”

“…Less than half of all included studies provided information about contraceptive methods used (or pregnancy) immediately before enrolment. In the 15 studies in which pregnancy occurred, 43,47,73,87,[98][99][100][101]105,106,108,111,113,114,116 nine distinguished between user or method failure (or both). 43,47,73,87,98,99,101,106,114 Active follow-up was conducted in three of the 17 studies.…”