| Methods |
100 sites in USA and 10 in Canada.
First 1/3 of participants were to have 13 treatment cycles and the remaining 2/3 were to have 6 treatment cycles. |
| Participants |
Sexually active, healthy women aged 18 to 45 years at risk for pregnancy with regular menstrual cycles, blood pressure <140/90.
Excluded recent pregnancy or lactation; contraindications to OCs; certain diseases; smokers aged 35 or more years; certain drugs or devices; recent DMPA use; and recent alcohol or substance abuse. |
| Interventions |
Norethindrone acetate (NETA) 1.0 mg plus EE 20 µg, with 75 mg ferrous fumarate on days 22‐28 (N=853 for 6 cycles, 318 for 13 cycles) versus norgestimate (NGM) 180‐215‐250 µg plus EE 25 µg (N=1236 for 6 cycles, 487 for 13 cycles). |
| Outcomes |
Weight change was primary outcome; contraceptive efficacy, cycle control, and safety were in earlier report (Hampton 2001).
'Breakthrough' bleeding or spotting defined as bleeding or spotting that occurred during the active pill days unless it was contiguous with menses.
'Amenorrhea' defined as two consecutive cycles without any bleeding or spotting. |
| Notes |
|
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
Allocated with block sizes of 11 |
| Allocation concealment (selection bias) |
Unclear risk |
No information |
| Blinding (performance bias and detection bias)
All outcomes |
Low risk |
Blinded (participants and at least the assessors at cycle 3). |
| Incomplete outcome data (attrition bias)
All outcomes |
High risk |
Lost to follow up reportedly 6.5% in NGM/EE group and 5.8% in NETA/EE group. Noncompleters were 21% of 6‐cycle groups; 42% to 40% of 13‐cycle groups, respectively. |
