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Plan B side effects

Plan B (so called “emergency contraception” or “morning after pills”) is a type of contraception that can prevent pregnancy after unprotected sex but it does not protect from sexually transmitted infections. Plan be can be used during 72 hours after unprotected sexual contacts. Morning after pills will not protect from getting pregnant if consumed before having sexual contact. Emergency contraception is most effective when taken as soon as possible after unprotected sex – sooner you take Plan B, more effective can be the result. Emergency contraception is not most comfortable method of contraception because of Plan B side effects but it is still better than unplanned and unwanted pregnancy or abortion. Most Plan B users experience several side effects which can occur during first week or even later.

Emergency contraception pills can be purchased without any prescription or proof of age. According to health experts, Plan B effectiveness can reach 89-90% if used during 72 hours after unprotected sex. Plan B can be more effective if used during first 24 hours after unprotected sex – the effectiveness can be 94-95%. If plan B used between 25-72 hours after unprotected sexual contact, the success rate drops to 58-60%. In general, effectiveness of emergency contraception depends also from the day of menstrual cycle.

Plan B side effects – When Plan B is recommended

  • Absence of any kind of contraception combined with unprotected sex;
  • Condom accidents (broken condom, wrongly used condom, expired condom, etc.);
  • Mistakes during use of barrier contraception (wrongly installed cervical cup, diaphragm slipped out of place);
  • Missed birth control pills (two and more missed pills);
  • Mistakes during withdrawal method of contraception (when man lost the control);
  • Sexual abuse or forced sex (including cases of rape).

Plan B side effects – Plan B mechanism of action

Emergency contraception pills contain high doses of hormones (type of progesterone, mainly levonorgestrel) which can interfere in normal monthly hormonal fluctuations typical for menstrual cycle. Plan B mechanism of action include the following:

  • Prevention or delay of mid-cycle ovulation;
  • Intervention in fertilization processes;
  • Changes in internal uterine lining and prevention of implantation.
  • Emergency contraception is not effective if woman is already pregnant.

Plan B side effects – Plan B contraindications

  • Pregnancy,
  • Allergy or hypersensitivity to hormones (especially to levonorgestrel),
  • History of uterine bleeding,
  • Obesity (BMI more than 25),
  • Period of hormonal treatments.

Plan B side effects

Plan B side effects

Menstrual cycle and period

Emergency contraception can cause unexpected irregular uterine bleeding. This side effect is the main symptom that can persist for days after taking emergency contraception. In most cases after next normal monthly menstrual period all bleeding symptoms (including bloody and brown discharge) disappear. Sometimes following menstrual period can be heavier and longer. Rarely women experience lighter period after morning after pills.

In general, emergency contraception can trigger menstrual disturbances during following 2-3 months. In most cases menstrual abnormalities are temporary (especially when plan B is used correctly according to instructions). Type of menstrual dysfunction depends on where exactly you are in your cycle when you take morning after pills.

If you don’t get menstrual period within three weeks, pregnancy test would be recommended.

General discomfort – nausea, vomiting, dizziness.

After morning after pills many women experience mild to moderate upset-stomach feelings including nausea and vomiting. This side effect explained by high dose of progesterone in morning after pills. Some experts consider nausea and vomiting during first 24 hours after taking pills normal. In cases of non-stop severe nausea and vomiting women should visit their doctor.

In cases of vomiting within two hours of taking Plan B, stomach could lose the necessary dose of medication which would not been fully absorbed into general bloodstream. Doctor could recommend additional dose of plan B.

Some women could experience temporary dizziness, headaches or fatigue after taking Plan B. Medical experts explain it by relaxation of muscle cells in blood vessels due to hormone progesterone component in morning after pills.

Pelvic pain or abdominal pain

Plan B pills (mainly progesterone component) could affect uterine musculature and trigger mild to moderate pelvic pain, uterine cramps or abdominal pain.

Breast tenderness

Unexpected breast tenderness also can be linked to Plan B. It is very common reaction/response to hormonal pills.


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