Health Information Woman Health

Information on Progestogen-only Injectable Contraceptives

Progestogen-only injectable

It is a synthetic hormone (progestogen). It prevents pregnancy by preventing the release of eggs from the ovaries, thickening the cervical mucus and creating a hostile endometrium environment for fertilisation.

• Regular Injection.
• The injection should be given every 13 weeks.
• If you cannot attend as scheduled, please return to the Maternal and Child Health Centre (MCHC) within 7 days before the due date. Please do not delay your injection.
• Before each injection, we will review your age, any change of your medical history and related information to assess whether you need to change to another more suitable contraceptive methods.

Advantages

• It is a highly effective method. The pregnancy rate is less than 1% per year.
• It is convenient for those who do not wish to take a pill daily or use a condom every time when having sex.
• It is suitable for breastfeeding mothers since it does not affect the volume and quality of breastmilk, and the health of their children.
• It does not contain oestrogen, and is suitable for women who cannot use contraceptive methods containing oestrogen.

Side Effects

• Headaches, dizziness, breast tenderness and mood change are the most common side effects at the initial period of use and usually subside within the first few months.
• Weight gain associated with Progestogen-only injectable mainly occurs in the first year. Women gain an average of 2.5kg in the first year of receiving Progestogen-only injectable.
• Majority of the women would have irregular menses, diminished menstrual flow or amenorrhoea, which is related to the hormonal effect of the progestogen, and so there is no need to worry. If you have persistent heavy or prolonged menstruation or any signs and symptoms of pregnancy after the injection, please return to the MCHC for assessment.
• Generally, it takes 6 to 9 months to resume normal ovulation following discontinuation of the Progestogen-only injectable. Therefore, it takes some time for return of fertility after stopping the injection.

Women who are not suitable to use Progestogen-only injectable

• Women with confirmed pregnancy, cancer of the breast or reproductive organs, meningioma, serious medical diseases and unexplained vaginal bleeding.

Please seek medical assessment as soon as possible if you have the following symptoms:

1. Bad fainting attack or collapse or seizures
2. Headaches and sudden onset of visual problems, such as seeing “flashing lights” & bright zig-zag line and blurred or distorted vision
3. Slurring of speech
4. Weakness or paraesthesia affecting any arms, legs or one side of the body
5. Unexplained breathlessness with or without coughing blood
6. Severe central chest pain or sharp pains in either side of chest
7. Severe calf pain (not related to trauma nor after exercise)
8. Severe abdominal pain
9. Unusual vaginal bleeding (e.g. persistent vaginal bleeding or heavy vaginal bleeding)
10. Yellowing of your skin and eyes (Jaundice)
11. Signs and symptoms of pregnancy
12. Tinnitus, hearing loss, loss of smell and memory loss

Will Progestogen-only injectable increase the risk of having breast cancer, meningioma and cancer of female reproductive organs ?

• Cancers can develop whether or not you are using the Progestogen-only injectable.
• Breast cancer: Studies showed that for women using Progestogen-only injectable has slightly higher to similar rate of breast cancer than non-users of contraceptive pill at the same age.
• Meningioma: Studies showed that for women using Progestogen-only injectable may increase their risk of having meningioma.
• Ovarian and endometrial cancer: Studies suggested that women who are using Progestogen-only injectable have a decreased risk of developing ovarian cancer and endometrial cancer.

Effect on Bone Mineral Density

• Overseas studies showed that the use of Progestogen-only injectable for more than two years is associated with a small reduction in bone mineral density. After discontinuation, the bone mineral density recovers in women aged 18 to 45. There is no evidence that the use of Progestogen-only injectable increases the risk of bone fractures.
• We suggest women who are using Progestogen-only injectable to have adequate calcium intake, sun exposure and do weight bearing exercise every day. If you have other risk factors for osteoporosis like history of fracture, alcoholism, smoking, low body mass index, inadequate calcium intake, family history of osteoporosis, endocrine diseases, e.g. thyroid disease, parathyroid disease or on long-term steroid, please discuss with your doctor to see if you can use Progestogen-only injectable. For more information, you can refer to "Osteoporosis in women" and "Meeting your calcium needs" leaflets.