Does Ella Cause A Delay In Your Period?

In our latest question and answer, the pharmacist discusses how the emergency contraceptive Ella can affect the timing of your period.

Dec 30, 2017

June asked

I took Ella  one after having sex with my partner. However, we used a condom and my partner did not ejaculate inside of me so there was no chance of semen entering my vagina. My period is currently approximately 5 days late, I have read that until the period is 7 days late there is no need to be concerned, but I fear I have scared myself by reading horror stories on internet forums. But My period can be erratic.I took a pregnancy test and it was negative, should I be concerned?

Answer

Ella (ulipristal) is an emergency contraceptive, and is thought to work either delaying or inhibiting ovulation in women. It may also alter how a fertilized egg implants into the uterus. Studies have shown that it is effective in preventing pregnancy after unprotected sex for up to 5 days after intercourse (unlike Plan B which is typically effective for up to 3 days after intercourse).

As Ella affects progesterone receptors in the body, it is well known to cause changes to the menstrual cycle. Having your period delayed after administration is not uncommon. 

Per the clinical trials for Ella, the following were the most commonly reported side effects in regard to menstrual cycle changes:

Most Common Ella Side Effects

Dysmenorrhea

Dysmenorrhea, or painful periods, occurred in 7—13% of women.

Increased Menstrual Cycle Length

Menstrual cycle length was increased by an average  of 2.5 days for all patients. This increased cycle length only occurred for the cycle in which Ella was taken. Most patients returned to normal in the next cycle.

Early Menses

Menses occurred more than 7 days early in 7% of women. Most patients returned to normal in the next cycle.



Delay In Menses

Over 19% of patients reported a delay in menses of more than 7 days. 



Breakthrough Bleeding

Breakthrough bleeding was reported in 9% of women.


As you can see from the data above, delayed periods are quite common and has been reported in 19% of women. Your period will most likely return to normal your next cycle.


It should be noted that it is generally recommended that pregnancy should be ruled out if there is a delay in your period for more than 1 week. If this does occur, it doesn't necessary mean you are pregnant as Ella can also cause amenorrhea (a lack of menses).



Still, If one week has elapsed since you should have gotten your period, make an appointment with your doctor to rule out pregnancy. If you are not pregnant, you can likely expect your next cycle to return to normal.

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