Levonorgestrel is the only hormone in Plan B; estrogen is not present in this form of emergency contraception.
Alesse birth control pills are a combination estrogen (ethinyl estradiol) and progesterone (levonorgestrel) pill.
It contains the ethinyl estradiol and levonorgestrel, two forms of the female hormones estrogen and progesterone.
The emergency pill contains a hormone called progestin levonorgestrel.
It's been reported that pregnancy occured for 1 out of 1000 women with the Levonorgestrel (LNg) intrauterine device.