Ortho Micronor

How Does It Work?

Because Ortho Micronor contains only a progestin, it is slightly less effective than pills that contain both an estrogen and a progestin (known as combined oral contraceptives). This and other progestin-only oral contraceptives stop ovulation in only about half of the women who take them.
Therefore, since this drug is not very effective at preventing ovulation, it also relies on other mechanisms to prevent pregnancy. Ortho Micronor alters the lining of the uterus (called the endometrium), making it less receptive to an embryo. It also changes the cervical mucus (the fluid of the cervix, which is the lower, narrow part of the uterus that is connected to the vagina), making it more difficult for sperm to enter the uterus.
Unlike combined oral contraceptives, there are no inactive or "placebo" pills in each pack of Ortho Micronor. Every tablet contains the active hormone, and there is no break in between pills or packs. Because there are no breaks, menstrual periods often occur at irregular intervals.

When and How to Use Ortho Micronor

General considerations for when and how to use this medicine include the following:
  • Ortho Micronor comes in tablet form. It is taken by mouth once a day.
  • Missing pills or taking them late is more likely to result in pregnancy, compared with combined oral contraceptives. It is essential that you take them at exactly the same time every day.
  • Each pack of Ortho Micronor contains 28 pills. Be sure to take them in order. Once you finish a pack, start a new one right away.
  • You may have your period early or late while taking this drug. Keep taking the pill either way; do not stop Ortho Micronor during your period.
  • You can take your dose with food or on an empty stomach. If the medication bothers your stomach, try taking it with food.
  • Make sure you know exactly what to do if you miss any pills or take them even a few hours late. In some circumstances, you may need to use a backup method of contraception, such as condoms.
  • For the medication to work properly, it must be taken as prescribed. Ortho Micronor will not work if you stop taking it.
Last reviewed by: Kristi Monson, PharmD
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