Progestogen-only Injectable (POI) Contraception

Progestogen-only injectable contraception is a hormonal type of contraception that is given through an injection. It contains a synthetic form of the hormone progesterone, known as progestin or progestogen. They provide protection against pregnancy for up to 8 to 14 weeks.


  • Medroxyprogesterone acetate (DMPA)
  • Norethisterone enanthate (NET-EN)

Mechanism of action

  • This hormone works primarily by suppressing ovulation (preventing the release of an egg from the ovaries).
  • It also thickens cervical mucus, making it more difficult for sperm to reach and fertilize an egg.
  • It can thin out the uterine lining, making it less suitable for the development of the fertilized egg.


When used correctly (getting the injection on time), progestogen-only injectable contraception is highly effective, approximately 0.2% in the first year of use. However, real-world effectiveness may be slightly lower due to missed or delayed injections and is typically about 6%.



  • Convenience – do not need to remember to take a daily pill, and it offers long-lasting protection.
  • Very effective compared to oral pills or condoms.
  • Can be used to treat conditions or symptoms in endometriosis, adenomyosis or uterine fibroids.
  • Long-term users may lower the risk of developing these conditions.
  • Can provide relief from heavy or painful periods.
  • Effectiveness is not affected by weight.
  • Does not interfere with sexual spontaneity.
  • Can be used while breastfeeding.


  • Must be administered by a healthcare provider every 8 -14 weeks (depending on the type)
  • Does not protect against sexually transmitted infections (STIs).
  • Irregular bleeding can be a nuisance for some users.
  • It may take several months after discontinuation for fertility to return to normal (up to 1 year in some women).

Side Effects:

  • Change in menstrual cycles – include irregular menstrual bleeding (which may be lighter or heavier). Some women will experience a complete absence of periods (amenorrhea), which can be beneficial for those with heavy or painful menstruation (in conditions such as adenomyosis or endometriosis).
  • Other side effects include weight gain, especially in younger women with higher BMI, mood changes, headaches, breast tenderness.
  • Uncommon – acne, decreased libido, hot flushes, hair loss and vaginitis.
  • Some individuals may also experience a decrease in bone density with long-term use, so it’s important to discuss this with a healthcare provider. Fortunately, this will revert to normal after discontinuation.

Who should not use the injectables.

These injections are safe for the majority of women of reproductive age. However, there are certain medical conditions that makes these unsuitable:

  • Known or suspected pregnancy.
  • Before evaluation of genital bleeding.
  • Liver disease, including tumors.
  • Cancer of the breast (past or present).
  • Hypersensitivity to any component of the product.

Timing of first injection (Initiation):

No additional protection needed if started –

  • up to Day 5 of menses.
  • switching from COCs: injection no later than Day 5 of pill-free interval.
  • switching from intrauterine device: initiate immediately on the day of removal.
  • switching from implant: initiate immediately on the day of removal.
  • postabortion (spontaneous or induced): initiate immediately.
  • postpartum non-breastfeeding: generally 3–4 weeks postpartum.
  • fully breastfeeding: initiate 6 weeks or longer.
  • perimenopausal: begins by day 5 of menses.

If not in line with the above criterias, then a woman needs protection for 7 days (using a condom)

What you need to know prior to injection

  • This is a good choice for women who has completed her family and / or has certain gynaecological problems associated with painful or heavy menstruation. Reduction in flow or absence of menses will offer relief.
  • Women should be able to accept changes in menstrual bleeding (including absence of menses) and up to 1 year delay in return of fertility.
  • Get adequate calcium intake.
  • If worry about weight gain, women should limit their calorie intake and get regular exercise.
  • Must be able to come on time for next injection. The interval will depend on the type of injectables given – please ask your healthcare provider and make sure you return for the next injection on time. Delay in the administration of the injectable may result in unplanned pregnancy.

See your healthcare provider if you have the following symptoms:

  • Injection site reactions – severe pain and swelling.
  • Pelvic/lower abdominal pain: need to exclude ectopic pregnancy.
  • Prolonged or heavy vaginal bleeding.
  • Yellowish discoloration skin (jaundice), light coloured stools.
  • Severe abdominal pain or leg swelling as these could be signs of a blood clots.

To print a pdf file, please click HERE

Progestogen only pill (POPs)

This type of pill does not contain oestrogen and the dose of progestogen is significantly lower than in those used in combined oral contraceptive pills (COC). It is also called the “mini-pill” and is useful for women who do not want pills that contain oestrogen or in situations where the oestrogen is not suitable for medical reasons. They are a highly effective method of birth control when taken correctly.

Formulation – Available formulations are:

  • Norethisterone 350 ug (NET) – (Noriday)
  • Levonorgestrel (LNG) 30 μg
  • Desogestrel (DSG) 75 μg – (Cerazette)

Levonorgestrel (LNG) and norethisterone (NET) are grouped as “traditional’ POPs”

Mechanism of action

  • It prevents sperm penetration via thickening of the cervical mucus.
  • It may prevent the release of the egg from the ovary (inhibit ovulation).
  • It may prevent implantation because of thinning effects on the endometrial layers.


  • POPs are rapidly reversible.
  • Suitable and safe for women above 35 years old.
    Safe and suitable for breastfeeding mothers.
  • Does not contain oestrogen, therefore suitable for women with certain medical condition (such as hypertension, diabetes, and migraine) that are not suitable for pills that contain oestrogen (such as the COC pills).
  • There are several non-contraceptive health benefits of POPs and include: decreased menstrual blood loss with lowered risk of anaemia, decreased period pain (dysmenorrhea), decreased cyclic mood changes or other premenstrual syndrome problems, protection from endometrial cancer, decreased pain from endometriosis, decreased pelvic inflammatory disease (from thickened, impenetrable cervical mucus).


  • Changes in menstrual bleeding pattern and this varies from intermittent irregular spotting or prolonged spotting to total absence of menstruation. In women with pre-existing heavy menstrual flow or pain associated with menses, the absence of menstruation will be an advantage and beneficial.
  • There is no protection from sexually transmitted infections (STI) or HIV.
  • Narrow time window for missed pills, therefore must be taken at the same time every day. Therefore, this is less effective if a person is not compliant to regular pill taking.


As with all oral pills, the effectiveness of POPs is user-dependent. Correct and regular pill-taking is important. If used perfectly, it may be more than 99% effective; but with typical use, the risk of pregnancy during the first year has been estimated at about 9%. Overall, it is generally slightly lower than the combined oral contraceptive pills (COC) due to the narrow window of missed pill duration.

Side effects

  • Irregular menstruation is not uncommon but usually improves with continuous use. It is usually spotting or light bleeding only. With continuous use, some women may not have menses at all.
  • Functional ovarian cyst – this is seen via ultrasound scan and is usually small and resolves on its own.
  • Minor side effects include headache, breast tenderness, nausea, and changes in mood or libido. Sometimes skin changes such acne or hirsutism may present but this is uncommon. Weight gain has been a concern but is generally not a significant problem in many women. These minor side effects often improve with time. Serious side effects are rare.

Who Should Not Use Progestogen-Only Pills:

  • Women with certain cardiovascular conditions or a history of stroke.
  • Women who are or may be pregnant.
  • Women with severe liver disease.
  • Women with unexplained vaginal bleeding.
  • Women with current or past history of breast cancer.

Instruction for pill-taking

  • Some medications may interact with POPs. Inform your healthcare provider about all the medications that you are currently taking before starting the POPs.
  • Start the pill on the first or second day of your normal menses. Protection is immediate and you do not need extra precaution. Or you can start anytime in your menstrual cycle if you are sure you are not pregnant (eg no prior unprotected intercourse for at least 2 weeks or after a negative pregnancy test). You will need protection for at least 2 days for the pills effect to start.
  • POPs must be taken at about the same time every day, without a break, including during your bleeding days or when having a period.
  • Set an alarm for reminder every day.
  • You can take POPs with or without food.
  • If a pill is missed or if taken late, have a back-up method available or abstain from sex for a period of time as detailed below.
  • Vomiting or diarrhoea – take another pill immediately. If this occurs within the 3 hours for (traditional POP) and 12 hours (for DSG POP), then the effective is still the same. However, if it exceeds the time limit, treat this as missed pills and see the instructions below.

Missed pills – what to do

  • Traditional POPs (norethisterone (NET) 0.35 mg or levonorgestrel (LNG) 30 μg) – If you miss a pill by more than 3 hours, take the missed pill as soon as possible even if it means taking two pills in one day. Continue taking the pills at your regular time. You will need additional contraception (e.g condoms) for the next 48 hours. If unprotected intercourse occurs then emergency contraception must be considered.
  • Desogestrel (DSG) 75 μg – (Cerazette) – If you miss a pill by more than 12 hours, take the missed pill as soon as possible even if it means taking two pills in one day. Continue taking the pills at your regular time. You will need additional contraception (e.g., condoms) for the next 48 hours. If unprotected intercourse occurs then emergency contraception must be considered.

Click HERE for more information on what to do if missed the POPs pills.

See your healthcare provider if you have the following symptoms:

  • Pelvic/lower abdominal pain: need to exclude ectopic pregnancy.
  • Prolonged or heavy vaginal bleeding. A sudden skipped period, especially after a pattern of regular bleeding cycles: needs to exclude pregnancy.
  • Yellowish discoloration skin (jaundice), light coloured stools.
  • Severe abdominal pain or leg swelling as these could be signs of blood clots.

To print a pdf copy, click HERE

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