what is this used for loestrin
2.5 Stars. Lo Loestrin Fe is the brand name for norethindrone acetate and ethinyl estradiol, a prescription birth control medicine that's used to prevent pregnancy. The drug contains female hormones that prevent ovulation and also causes changes in the cervical mucus and uterine lining, which makes it harder for sperm to reach the uterus and for a fertilized egg to attach to the uterus.