After a single 30 mg dose of Ella (ulipristal acetate), when can Loestrin (combined estrogen‑progestin oral contraceptive) be started?

Starting Loestrin After Ella (Ulipristal Acetate)

Wait at least 5 days after taking Ella before starting Loestrin, then use backup contraception (condoms or abstinence) for 7 additional days after starting the combined oral contraceptive. 1, 2

Timing Algorithm

Step 1: Wait Period After Ella

• Do not start Loestrin for 5 days after taking ulipristal acetate 30 mg 1, 2
• This delay is necessary because ulipristal acetate has antiprogestin properties that may reduce the effectiveness of hormonal contraceptives if started simultaneously 1
• Starting combined oral contraceptives immediately after Ella may also decrease Ella's ability to delay ovulation 1

Step 2: Initiate Loestrin on Day 6

• Begin Loestrin no sooner than 5 days (120 hours) after taking Ella 1, 2
• The combined oral contraceptive can be provided or prescribed at the time of Ella use, with clear instructions to delay starting 1

Step 3: Backup Contraception Requirements

• Use barrier methods (condoms) or abstain from intercourse for 7 days after starting Loestrin 1
• This 7-day backup period is standard for combined hormonal contraceptives started outside the first 5 days of menstrual bleeding 1

Evidence Behind the Recommendation

Why the 5-Day Wait Matters

The most recent 2024 CDC guidelines explicitly address this interaction, noting that studies show conflicting effects when ulipristal acetate and hormonal contraceptives are taken close together 1:

• Two studies found that starting oral contraceptives within 5 days of Ella decreased Ella's ability to delay ovulation (ovulation rates: 27% with COC+UPA versus 3% with UPA alone; 45% with POP+UPA versus 3% with placebo+UPA) 1
• One high-quality 2020 study demonstrated that women who delayed restarting COCs for 5 days after ulipristal acetate had significantly fewer ovulations with pregnancy risk compared to immediate restart (17.4% versus 0%, p=0.042) 3
• The FDA label for Ella explicitly states: "After ella use, initiate or resume hormonal contraception no sooner than 5 days after the intake of ella" 2

Why 7 Days of Backup Contraception

• Combined oral contraceptives require 7 days to establish reliable ovulation suppression when started outside the first 5 days of menses 1
• This is distinct from progestin-only pills, which require only 2 days of backup 1

Common Pitfalls to Avoid

Pitfall #1: Starting Loestrin immediately after Ella

• This reduces the effectiveness of both medications 1, 3
• The antiprogestin effect of ulipristal acetate can interfere with progestin-containing contraceptives 1

Pitfall #2: Using only 2 days of backup contraception

• Combined oral contraceptives like Loestrin require 7 days of backup, not 2 days 1
• The 2-day rule applies only to progestin-only pills 1

Pitfall #3: Waiting for next menstrual period

• Unnecessary delay increases pregnancy risk during the waiting period 1
• Fertility returns rapidly after Ella use 2

Pregnancy Testing

• If withdrawal bleeding does not occur within 3 weeks of starting Loestrin, perform a pregnancy test 1
• Ella may delay the next expected menses by 2-3 days on average, with 19% of women experiencing delays >7 days 2

Alternative Immediate Options

If immediate contraceptive protection is needed:

• Copper IUD: Can be inserted immediately after Ella with no waiting period and provides superior emergency contraception 1
• Progestin-only pills: Can be started immediately with only 2 days of backup contraception required 1
• Etonogestrel implant: Can be inserted immediately with 7 days of backup contraception 1