Nowadays, there are many different contraception methods available, but which of them are correct and effective? Can the urban myths on alternative contraception methods successfully reduce the chance of pregnancy? Apart from the risk of pregnancy, sexual health and safety are also important concerns. We need to understand which method is the most effective in preventing HIV and other sexually transmitted infections.

 General contraceptive methods

1. Oral contraceptives / Emergency contraceptive pills (EC pills)

How to use
Cons/ side effects
Oral contraceptives
There are two main types:
  • Combined Oral Contraceptives (COC) comes in 21-day or 28-day packs. For both packs, the first pill is taken on the first day of menstruation. When using the 21-day pack, there should be a break of 7 days before starting the next pack. For the 28-day pack, the pills can be taken daily without a break.
  • Progestogen Only Pills (POP) must be taken daily without a break.
Around HK$80-150 per pack Cost may vary due to different brands, dosages, pharmacological companies etc.
  • Very reliable with 98% success rate in contraception
  • Not permanent, can stop anytime
  • Improve skin condition
  • Headache, nausea
  • Edema, weight gain
  • Breast swelling
  • Clotting of blood vessels

    *Cannot prevent HIV and STIs infection

Emergency contraceptive pills (EC pills)
There are two main types:
  • Progestogen: one pill must be taken within 72 hours after unprotected sexual intercourse
  • Ulipristal acetate: one pill must be taken within 120 hours after unprotected sexual intercourse
Around HK$200
Can be used after unprotected sexual intercourse
  • Even with correct administration (taken within 72/120 hours), there is still a 2% risk of pregnancy. If it is taken only after the above mentioned time period, successful contraception cannot be achieved.
  • Headache, dizziness, nausea, fatigue
  • Irregular menstruation, painful menstruation, abdominal pain, backache, painful and swollen breasts

    *Cannot prevent HIV and STIs infection
There are two main types:
  • Progestogen only: injected once every 3 months
  • Combined type: injected once every month
Around HK$100-200 per injection
  • High successful rate, according to research, the chance of pregnancy for women using contraceptive injection in the first year is 0.2-6%
  • Long duration of contraception: for each injection, the effect is sustained for 1 or 3 months
  • Immediate contraceptive effect after injection
  • Must be administered by medical professionals regularly
  • Similar side effects as those of oral contraceptives
  • Fertility can only be restored one year after last injection, not recommended for women planning to get pregnant in short term

    *Cannot prevent HIV and STIs infection

If I forgot to take oral contraceptive pills, what should I do?

Oral contraceptives must be taken regularly to achieve contraceptive effects. Irregular use will lower the effects of contraception. If you forgot to take once, you should immediately take the missed pill at the time you remember. The next pill should be taken at the assigned time when you should take oral contraceptives. For example, 12 pm is the assigned time for taking the pill every day. If at 4 pm on the third day, you realise you forgot to take the pill, you should immediately take one pill, then take the next pill at 12 pm for the next day and so on.

Also, for every sexual intercourse during this menstruation cycle, other external contraceptive methods should supplement oral contraceptives. If two or more pills have been missed within the first five days of the start of regimen, and sexual intercourse has been performed during this period, you should consult doctors on emergency contraceptive methods.

Are oral contraceptive pills more effective than injectables? What is the success rate of injectables? What are the side effects?

Both oral contraceptives and injectables suppress ovulation by synthetic hormones, which changes the structure of the uterine lining so that the fertilised egg cannot implant onto the uterus. Also, synthetic hormones can increase the viscosity of cervical secretion to make sperms difficult to pass through and enter the uterus. If used properly, both oral contraceptives and injectables have high efficacy.


Their failure rates are as follows:

Oral contraceptives (combined)
Oral contraceptives (progestogen only)
Injectables (progestogen only)

Are emergency contraceptive pills effective?

Although emergency contraceptive pills have high effectiveness in preventing pregnancy, they are not 100% effective. Even with proper usage, there is an about 2% failure rate. If women frequently use emergency contraceptive pills for contraception, the risk of pregnancy will be higher than using other routine contraceptive methods. This is why emergency contraceptive pills cannot replace routine contraceptive pills. Beware: for unprotected sexual intercourse taken place after taking emergency contraceptive pills, those pills will not protect you against pregnancy. Therefore, for future birth control, it is better to choose a long-term contraceptive method.


Contraception. The Family Planning Association of Hong Kong.

Oral contraceptive. Drug Office, Department of Health, HKSAR.

2. Intrauterine Contraceptive Device (IUCD)

How to use:

Insertion of the IUCD must be performed by a trained clinical professional. Before the procedure, doctors will first take a history and carry out a pelvic examination to assess whether the woman is suitable to undergo the procedure. After the procedure, regular follow-up is required.

There are two main types of IUCD: one is T-shaped and another one is shaped like an umbrella. For both types, there is a line at the bottom for doctors to check or self-monitoring. T-shaped IUCD, with respect to different models, needs to be replaced once every 5-10 years after being inserted. As for the umbrella-shaped IUCD, it needs to be replaced once every 5 years.

Price: varies from hundreds to thousands of HKD.



IUCD is a long-term contraceptive method. Once inserted, there will be contraceptive effects, thus it suits couples who require long-term birth control, such as those after pregnancy, at older ages, with enough children or unwilling to use other contraceptive methods. With IUCD insertion, user does not need to prepare before sexual intercourse and will not feel the presence of IUCD, so the sexual sensation and satisfaction will not be lowered. If the couples decide to give birth again, they can consult doctors to remove the IUCD. The chance of pregnancy can immediately be restored. IUCD has very high contraceptive effectiveness as the risk of pregnancy for women using IUCD in the first year is 0.6-0.8% only.

Cons/ Side effects/ Complications

  • Effects on menstruation: initially after insertion, there may be heavier menstrual flow, increased normal vaginal discharge, and slight menstrual pain.
  • Pelvic inflammatory disease (PID): generally, there is a low risk of PID complication.
  • Perforation of uterus: occurs in less than one out of every 1000 insertions, usually during the surgical procedure of inserting IUCD. Complications of perforation of uterus include internal bleeding, infection, and infertility.
  • Displacement or expulsion of IUCD: happens in about 5% of users, commonly occurs in first 3 months of using IUCD.
  • Cannot prevent HIV and STIs infection.



Intra-uterine contraceptive device, The Family Planning Association of Hong Kong.

Information for Intra-uterine contraceptive device, Family Health Service, Department of Health, HKSAR.

3. Diaphragm

Diaphragm is a dome-shaped soft rubber device placed inside the vagina to cover the cervix before sexual intercourse. The diaphragm and the spermicidal jelly applied on it act as double barriers to block sperms from entering the uterus, thus prevent the egg from encountering sperm and being fertilised. Spermicidal jelly can kill sperms or lower their level of activity.

How to use:

First, spermicidal jelly is put on both sides of the rubber dome and around the rim. Fingers or an inserter are used to insert the diaphragm into the vagina until the entire cervix is covered. Then the fingers can be released or the inserter can be taken out.

Within 6-8 hours after sexual intercourse, the diaphragm should not be removed and vaginal douching should not be performed, or else the spermicidal jelly will be washed away and the contraceptive effects will be compromised. If there is another sexual intercourse within 6 hours after inserting diaphragm, you can simply re-apply spermicidal jelly on the diaphragm via a syringe without the need to take out and re-insert the diaphragm. But the diaphragm cannot remain in the body for over 24 hours, or else it will give off foul smell or increase vaginal discharge.


It is only inserted before sexual intercourse, no pills or injectables are required, and users will not suffer from side effects of the synthetic hormones. The chance of pregnancy can be restored immediately if you stop using it.


  • Contraceptive effect is affected by whether the diaphragm is properly placed. If not properly inserted, there may be no birth control effect at all. Even if placed properly, the risk of pregnancy is still as high as 6-20%.
  • May lead to cystitis (bladder infection) and urethritis.
  • Both the diaphragm and the spermicidal jelly cannot be used independently for there will be no contraceptive effect in independent use.
  • Cannot prevent HIV and STIs.


Diaphragm, The Family Planning of Hong Kong.