Side effects of Postinor-2 (P2) on menstruation

Postinor-2 is safe for use and does not affect fertility. However, it has minor side effects that may alter menstruation or the menstrual cycle. Find out the side effects of Postinor-2 on menstruation.

Sad Black girl taking postinor-2 pill with a glass of water

Key Takeaways:

  • One of the most common side effects of Postinor-2, also called P2, is menstrual cycle disturbance. However, this pill does not damage the womb.
  • The side effects of Postinor-2 on menstruation include changes in the duration of the period, heavier menstrual flow, and irregular menstrual cycle patterns. The side effects can last from a few days to several days.
  • Postinor-2 is not designed to be taken as a regular birth control pill. If you are sexually active, it is best to speak with your doctor about using a regular birth control method, such as hormonal pills and IUDs.

If you had unprotected sex unintentionally and are on the lookout for a quick contraceptive solution to prevent pregnancy, you are not the only one who has been in that situation. People often purchase emergency contraceptives like Postinor 2 after one-off sexual intercourse to prevent contraception.

But is Postinor 2 safe?

The World Health Organisation (WHO) says emergency contraceptives are safe for everybody, including adolescents. Secondly, the organization also says emergency contraceptive pills don't affect future fertility. Postinor-2 does not cause damage to the womb.

Postinor 2 works by delaying ovulation by several days. While it is considered safe, Postinor 2 can cause side effects that affect your menstrual cycle, such as irregular periods. Postinor 2 side effects can last for a few days. However, the side effects often change or correct themselves over time.  

In this article, we will discuss how Postinor-2 works and the side effects of Postinor-2 on menstruation. We will also explore other possible side effects of postinor and when to see a doctor for menstrual cycle issues. 

Side effects of Postinor 2 on menstrual cycle

Postinor 2 can alter the menstrual cycle, causing missed periods, particularly in people who use it regularly. However, it often doesn’t cause serious side effects, even when taken more than once in a cycle. 

Side effects of Postinor 2 on menstruation include:

  • Changes in the length of the menstrual cycle
  • Seeing period later or earlier than expected
  • Changes in volume of flow (such as heavier or lighter flow)
  • Spottings

“These changes are often transient, and in the absence of any prior existing condition, periods are likely to return to normal patterns,” said Agbaje Michael (MBBS), Consultant Gynecologist and Obstetrician at Lagoon Hospitals, Lagos, told SemicHealth,

Postinor-2 does not harm a developing fetus; hence, does not induce abortion.

How Postinor-2 works

Postinor-2 is an emergency contraceptive pill (ECP) that contains levonorgestrel. Levonorgestrel belongs to a class of medications called progestins. Progestins work by preventing the release of an egg from the ovary, thereby preventing fertilization.

To explain more on how Postinor-2 works, Dr. Agbaje said “By virtue of their physiological effects, Postinor-2 also works by altering cervical mucus consistency (thickening it)”. 

Agbaje added that Postinor-2 may change the endometrial lining (lining of the uterus), making it less receptive to implantation and pregnancy.

However, evidence indicates that Postinor-2 may not reduce the pregnancy rate if taken after ovulation. Also, it cannot prevent implantation if taken after fertilization.

Wondering if Postinor-2 is affordable? Check the price of Postinor-2

How often should you take Postinor-2?

Postinor 2 is an emergency contraceptive and should be taken in situations like contraceptive accidents (e.g., torn condoms and forgotten pills) and coerced sex. 

It may not cause serious health risks if taken repeatedly; however, Postinor-2 is not designed to be taken as a regular birth control pill. Older studies indicate that Postinor has a failure rate of less than 1 and may only cause relatively few side effects if not more than 4 pills are taken per month.

“Postinor-2 is not advised for frequent use. Patients who plan regular unprotected sex should get other methods,” Agbaje said.  

When asked how many times in a monthly cycle will be considered as “frequent” for the use of Postinor-2, Agbaje said, “It can be extrapolated that more than once in a cycle is “frequent.” It’s advised best use is once in a cycle. Alternative regular methods are advised.”

Should you take Postinor 2 up to three times a month?

It is not healthy to take Postinor 2 three times a month. If you take Postinor 2 multiple times in a month (which is almost similar to one menstrual cycle), you should consider stopping. Instead, speak to your doctor about getting a regular birth control that will be ideal for you.

Read this article on how to take Postinor-2, if you are confused about how to take it.

Other side effects of Postinor 2 (P2)

Postinor-2 has some possible adverse effects. However, Postinor 2 side effects are often not serious and not long-lasting. 

The most commonly reported side effects of emergency contraceptive pills like Postinor 2 are irregular menstruation and vaginal bleeding disturbances or intermenstrual bleeding. Some people also report side effects like abdominal discomfort and nausea.

As written on the pill's consumer medicine information (CMI) leaflet, side effects of Postinor 2 include:

  • Tiredness
  • Nausea and vomiting
  • Dizziness
  • Stomach pain
  • Headache
  • Diarrhea
  • Breast tenderness
  • Skin reactions
  • Increased vaginal bleeding

For people who are sexually active: Read about regular birth control options you can opt for if you are not ready for conception .

When to see a doctor for menstrual cycle issues

Postinor-2 can interfere with your menstrual cycle; however, this is not always the case. Some people experience menstrual cycle issues caused by health conditions that affect the hormones. Health conditions that can affect your periods include polycystic ovarian syndrome (PCOS), pelvic inflammatory diseases, uterine fibroids, and endometriosis. 

Pregnancy, stress, and lifestyle factors can also contribute to abnormal changes in the menstrual cycle. Always check with your gynecologist if you notice changes, especially repeatedly with your period flow or menstrual cycle.

Your gynecologist will recommend some tests to rule out serious health conditions. If there is a need to start you on a treatment plan, they will discuss this further with you.