When to switch to Micronor (norethindrone) if previously used Depo (medroxyprogesterone acetate)?

From the Guidelines

You can start taking Micronor immediately if you're switching from Depo-Provera, but if it has been more than 7 days after your last menstrual period, you should use a backup method of contraception for 2 days, as recommended by the most recent guidelines 1. When switching from Depo-Provera to Micronor, it's essential to consider the timing of your last menstrual period to determine the need for backup contraception. According to the 2024 U.S. Selected Practice Recommendations for Contraceptive Use, if you start Micronor more than 5 days after your last menstrual period, you should use a backup method, such as condoms, for 2 days 1.

• Key points to consider when switching from Depo-Provera to Micronor include:
  • Start Micronor immediately, regardless of the timing of your last Depo-Provera injection
  • Use a backup method of contraception for 2 days if you start Micronor more than 5 days after your last menstrual period
  • Take Micronor at the same time every day without breaks between packs for maximum effectiveness
  • The standard dosage is one 0.35 mg tablet daily The transition from Depo-Provera to Micronor is relatively straightforward, as both medications are progestin-only contraceptives that prevent pregnancy primarily by thickening cervical mucus and thinning the uterine lining, as noted in the CDC's guidelines for contraceptive use 1.
• Benefits of switching to Micronor include:
  • Quicker reversibility when discontinued compared to Depo-Provera
  • Daily adherence is required, which can help with menstrual cycle regulation
  • Micronor is a progestin-only pill, which can be beneficial for women who cannot use combined hormonal contraceptives.

From the Research

Switching to Micronor from Depo

There are no direct studies that provide guidance on when to switch to Micronor if Depo was used previously. However, some studies provide information on the effects of Depo and other progestins:

• The study 2 found that adolescents who used Depo had a high discontinuation rate due to irregular bleeding and weight gain.
• The study 3 found that Depo improved physical health but had no significant effect on mental health and sexual function.
• The study 4 found that medroxyprogesterone acetate (MPA), the active ingredient in Depo, increased HIV-1 replication in human peripheral blood mononuclear cells.
• The study 5 compared the effectiveness of norethindrone acetate (NETA) and dienogest in alleviating pain associated with endometriosis, but did not provide information on switching from Depo to Micronor.
• The study 6 found that combined norethindrone acetate and low-dose ethinyl estradiol therapy reduced vaginal bleeding in postmenopausal women compared to combined conjugated equine estrogens and medroxyprogesterone acetate therapy.

Key Points to Consider

• Depo can cause irregular bleeding and weight gain, leading to discontinuation 2.
• MPA can increase HIV-1 replication 4.
• NETA can be effective in alleviating pain associated with endometriosis 5.
• Combined norethindrone acetate and low-dose ethinyl estradiol therapy can reduce vaginal bleeding 6.

Potential Next Steps

• Consult with a healthcare provider to discuss individual circumstances and determine the best course of action.
• Consider the potential effects of Depo and other progestins on physical and mental health.
• Evaluate the effectiveness of alternative contraceptive methods, such as Micronor, in alleviating symptoms and improving overall health.