Progestogen injection is one of the effective contraceptive methods, which contain the hormone ‘progestogen’. It basically prevents the release of an egg from the ovaries. It also thickens the mucous from the cervix. Therefore, it prevents sperms reaching an egg. Progestogen injections can make the endometrium (the lining of the uterus) thinner, reducing the probability of the implantation of the fertilised egg.
There are two types of progestogen injections.
- Depot medroxyprogesterone acetate (DMPA)
- Norethisterone enanthate
Depot medroxyprogesterone acetate (DMPA)
DMPA 150 mg is given as a deep intramuscular injection into the buttock, thigh, or arm. Intramuscular DMPA releases the progesterone hormone into the blood in a consistent manner, and its action lasts about 12-13 weeks. It should be started within first five days of the menstrual cycle or within first five days after childbirth. If the mother is doing breast-feeding, DMPA injections can be delayed for six weeks after childbirth. For a long-term contraceptive effect, the DMPA injection should be repeated every 12 weeks. If a woman is late to get her DMPA injection more than five days from the scheduled date, the healthcare professional will rule out pregnancy before the next injection and advise her to use extra precautions such as condoms for 14 days after the injection. However, if a woman is late to take the injection less than five days, she doesn’t need to use an extra contraceptive method and can continue her DMPA injections as usual. DMPA is one of the highly effective contraceptive methods, and its failure rate is about 0.1-2 pregnancies, if 100 women were to use DMPA for one year.
Benefits of DMPA injections
- It is highly effective as a contraceptive method.
- It is injected every 12 weeks.
- It has minimal interactions with other drugs.
- It reduces the risk of endometrial cancer significantly (by 80 %).
- It reduces the risk of ectopic pregnancy, iron deficiency anaemia, fibroids, pelvic inflammatory disease (PID), and functional ovarian cysts.
- It does not increase the risk of stroke, ischaemic heart disease, deep-vein thrombosis (DVT), or pulmonary embolism (PE) due to lack of oestrogen hormone.
- It improves premenstrual syndrome.
- It can be used to manage painful or heavy periods.
- It is useful for a woman, who has difficulty remembering to take a pill daily.
Adverse effects of DMPA injections
- Injection-site reactions
- Absent menstruation
- Weight gain in the first year
- Continuous irregularities of the menstrual cycles
- Delay in return of fertility after discontinuation of the injections (about six months, but it may be up to nine to ten months)
- Long-term use may slightly increase the risk of osteoporosis due to low oestrogen levels.
If a woman has one of the following conditions, she cannot use DMPA injections.
- Pulmonary embolism (PE)
- Deep-vein thrombosis (DVT)
- Several risk factors for ischaemic heart disease
- Migraine with aura while the woman is using DMPA.
- Vaginal bleeding, which has not been evaluated.
- Any active liver diseases
- Breast cancer
- Ischaemic heart disease
- History of ischaemic heart disease
- History of stroke
- Diabetes for more than 20 years
- Diabetes with complications (macrovascular or microvascular)
- Hypertension with cardiovascular disease
This injection is not nearly so widely used. Norethisterone enanthate 200 mg is given as a deep intramuscular injection very slowly into the buttock within first five days of the cycle or immediately after childbirth. It releases the norethisterone hormone into the blood in a constant way over eight weeks and should be repeated once after eight weeks. If the neonate has had severe or continuous jaundice, the mother, who has taken norethisterone enanthate injections already, should withhold the breastfeeding.
(Photo courtesy: Blake Patterson)