What is the best emergency contraceptive option for a 27-year-old female within the first 3 days of unprotected sex?

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From the Guidelines

The best emergency contraceptive option for a 27-year-old female within the first 3 days of unprotected sex is ulipristal acetate (ella), as it has been shown to be more effective than levonorgestrel, especially in women with higher body weight 1.

Key Considerations

  • Ulipristal acetate is a progesterone receptor modulator that can be used up to 5 days after unprotected sex, but is most effective when taken as soon as possible after the event.
  • The copper IUD is also a highly effective option, with a failure rate of less than 1%, but its use may be less common due to the need for insertion by a healthcare provider 1.
  • Levonorgestrel (Plan B One-Step or generic equivalents) is still a viable option, but its effectiveness may be reduced in women with higher body weight, typically over 165 pounds 1.

Administration and Side Effects

  • Ulipristal acetate should be taken as a single 30 mg tablet as soon as possible after unprotected intercourse.
  • Side effects of ulipristal acetate are generally mild and may include headache, nausea, and fatigue.
  • It is essential to note that emergency contraception does not provide ongoing protection, and a reliable form of birth control should be used for any subsequent sexual activity.

Special Considerations

  • Women with higher body weight (over 165 pounds) may benefit from ulipristal acetate or the copper IUD, as these options may be more effective than levonorgestrel in this population 1.
  • The efficacy of emergency contraception may be affected by certain medications, such as antiretroviral agents, and healthcare providers should consider potential interactions when prescribing emergency contraception 1.

From the FDA Drug Label

Table 3: Summary of Clinical Trial Results for Women Who Received a Single Dose of ella (30 mg Ulipristal Acetate) Open-Label Study 48 to 120 Hours * Single-Blind Comparative Study 0 to 72 Hours * N = 1,242 N = 844 Expected Pregnancy Rate ** 5.5 5.6 Observed Pregnancy Rate ** (95% confidence interval) 2.2 (1.5,3.2) 1.9 (1.1,3. 1)

The best emergency contraceptive option for a 27-year-old female within the first 3 days of unprotected sex is ulipristal acetate (ella), as it has been shown to significantly reduce the pregnancy rate when taken within 72 hours after unprotected intercourse, with an observed pregnancy rate of 1.9% compared to an expected rate of 5.6% 2.

  • Key points:
    • Ulipristal acetate is effective when taken within 72 hours after unprotected intercourse.
    • The observed pregnancy rate was significantly reduced compared to the expected rate.
    • The study results support the use of ulipristal acetate as an emergency contraceptive option.

From the Research

Emergency Contraception Options

The best emergency contraceptive option for a 27-year-old female within the first 3 days of unprotected sex includes:

  • Levonorgestrel (LNG-EC): a progestin-only method that can be taken as a single 1.5 mg dose or two 0.75 mg doses 12 hours apart 3
  • Ulipristal acetate (UPA): a progesterone receptor modulator that can be taken as a single 30 mg dose 4, 5
  • Copper intrauterine device (Cu-IUD): a non-hormonal method that can be inserted up to 7 days after unprotected intercourse 6, 4, 7

Efficacy of Emergency Contraception Options

The efficacy of these options varies:

  • Levonorgestrel: prevents around 50% of expected pregnancies when taken within 72 hours of intercourse 6
  • Ulipristal acetate: may prevent almost two thirds of pregnancies when taken within 120 hours of intercourse, but its efficacy is similar to levonorgestrel when taken within 3-5 days 6, 5
  • Copper intrauterine device: probably prevents over 95% of pregnancies when inserted within 7 days of unprotected intercourse 6, 7

Safety and Side Effects

All emergency contraception options are extremely safe, with minimal side effects:

  • Levonorgestrel and ulipristal acetate: may cause nausea, vomiting, and menstrual disorders 4, 5
  • Copper intrauterine device: may cause cramping, bleeding, and other side effects associated with IUD insertion 7

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

An update on emergency contraception.

American family physician, 2014

Research

Interventions for emergency contraception.

The Cochrane database of systematic reviews, 2008

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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