How to initiate Lo Estrin (ethinyl estradiol and norethindrone) in a patient whose menstrual period has already started?

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Last updated: March 18, 2025View editorial policy

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From the Guidelines

To initiate Lo Estrin (ethinyl estradiol and norethindrone) in a patient whose menstrual period has already started, take the first pill on the first day of your menstrual bleeding or up to the fifth day of your period, and if starting after day 1, use a backup method like condoms for the first 7 days of pill use. This recommendation is based on the most recent guidelines from the U.S. Selected Practice Recommendations for Contraceptive Use, 2024 1. According to these guidelines, combined hormonal contraceptives (CHC) like Lo Estrin can be started anytime, but if started more than 5 days after menses started, the patient should abstain from sexual intercourse or use barrier methods (e.g., condoms) for 7 days.

Key Considerations

  • If starting on day 1, no backup contraception is needed.
  • If starting after day 1, use a backup method like condoms for the first 7 days of pill use.
  • Take one pill at the same time every day, following the order in the pack.
  • The 28-day pack contains 24 active pills followed by 4 inactive pills.
  • If you miss a pill, take it as soon as you remember, even if it means taking two pills in one day.
  • If you miss two or more pills, use backup contraception for 7 days.

Mechanism of Action and Side Effects

Lo Estrin works by preventing ovulation, thickening cervical mucus, and thinning the uterine lining. Side effects may include spotting, nausea, or breast tenderness, which typically improve after 2-3 months. Starting during your period helps ensure you're not pregnant and may reduce initial side effects. The guidelines from 2024 1 provide the most up-to-date information on initiating CHC, superseding previous recommendations from 2013 1.

From the FDA Drug Label

If a patient starts on Kariva® postpartum, and has not yet had a period, she should be instructed to use another method of contraception until a white tablet has been taken daily for 7 days. DAY 1 START Counting the first day of menstruation as “Day 1”, tablets are taken without interruption as follows: One white tablet daily for 21 days, one light-green (inert) tablet daily for 2 days followed by 1 light-blue (ethinyl estradiol) tablet daily for 5 days.

The patient should start Lo Estrin on the first day of her menstrual period, counting that day as Day 1. She should take one tablet daily for 21 days, followed by one light-green (inert) tablet daily for 2 days, and then one light-blue (active) tablet daily for 5 days. 2

From the Research

Initiating Lo Estrin in a Patient with an Ongoing Menstrual Period

  • According to the study 3, most patients can safely begin using hormonal contraception at any point in their menstrual cycle, suggesting that Lo Estrin (ethinyl estradiol and norethindrone) can be initiated in a patient whose menstrual period has already started.
  • The study 3 also mentions that delaying contraception to wait for the next menses or for an appointment creates unnecessary barriers for patients, implying that initiation of Lo Estrin should not be delayed.
  • However, the studies 4, 5, 6, and 7 do not provide specific guidance on initiating Lo Estrin in a patient with an ongoing menstrual period, as they focus on different aspects of oral contraceptives, such as cycle control, tolerability, and satisfaction.

Key Considerations

  • The study 3 emphasizes the importance of providing anticipatory guidance about common side effects, giving comprehensive information about available contraceptive choices, and honoring patients' preferences when initiating hormonal contraception.
  • The study 6 recommends that a pill containing the lowest hormonal content be utilized, but this may not be directly applicable to Lo Estrin, as the study does not specifically discuss this medication.
  • The studies 4 and 7 compare the efficacy and side effects of different oral contraceptives, but do not provide guidance on initiating Lo Estrin in a patient with an ongoing menstrual period.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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