4.9. Analysis.
Comparison 4: 20 ug ethinyl estradiol and 100 ug levonorgestrel, 28‐day versus 168‐day cycles for 6 months, Outcome 9: Mean bleeding days in second trimester (84 days)
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.