8.1
Methods
Injections
containing hormone formulation are given periodically to women to
prevent pregnancy.
Depot-medroxy progesterone acetate
(DMPA)
This is the commonest type of injectable
contraceptive. It is given in a dose of 150 mg intra-muscularly
every three months. It is marketed as Depo-Provera in India. It
can be prescribed in women where oestrogen is contraindicated.
Norethindrone Enanthate (NET-EN)
It is given in a dose of 200 mg intra-muscularly
every 2 months. Currently, it is not available in India.
Combined Estrogen and Progestin (monthly
Injections)
It is marked as cyclofem, cycloprovera
or mesogyna. These are monthly injections containing 25mg depomedroxyprogesterone
acetate and 5mg estradiol cypionate. These are yet not available
in India.
8.2 Mechanism of action (DMPA)
•
blocks LH surge and therefore prevents ovulation
• thickens cervical mucus
• alters the endometrial receptivity for
implantation
• suppression of FSH is not intense, thus
allowing follicular growth sufficient to produce estrogen levels
comparable to early follicular phase of a normal menstrual cycle
8.3 When to start injectable
contraceptive
(DMPA)
• after excluding pregnancy, injectable
contraceptives can be started at any time of the menstrual cycle,
preferably within first 5 days of menstrual bleeding when no back-up
method is needed. If given later in the cycle a back-up method
like condoms or spermicide should be used for at least the next
48 hours.
• it can be started as early as 6 weeks
after childbirth when the woman is fully or partially breast-feeding
her baby. In non-lactating mothers it can be given immediately
after childbirth or any time within 6 weeks without waiting for
return of menses.
• after an abortion, it can be started
immediately, or in the first 7 days, or any time later after excluding
pregnancy.
• women discontinuing the use of other
contraceptives can use injectables without any delay.
8.4 Advantages
•
very effective, long acting, reversible
• easy to maintain privacy
• not a coitus-related method
• no daily pill-taking is required
• allows some flexibility in return visits.
Client can return as much as 2 weeks early or late than due date
for injection
• quantity and quality of breast milk
is not affected. Can be used by nursing mothers as soon as 6 weeks
after childbirth
• no estrogen side-effects like dyslipidemia
and increased risk of heart attack etc.
• prevent ectopic pregnancies, endometrial
cancer, uterine fibriods
• may help in preventing ovarian cancer
and iron-deficiency anemia
• may make seizures less frequent in women
with epilepsy
• make sickle cell crises less frequent
and less painful
8.5 Disadvantages
•
changes in menstrual bleeding pattern, like irregular spotting
or bleeding, scanty periods are common, rarely heavy bleeding
may occur. Amenorrhoea, especially after first year of use, may
be disturbing in some women
• breast tenderness, weight gain, acne
and depression are bothersome side-effects
• return of fertility may take up to 9
months after the last injection which is longer than other reversible
contraceptive methods
• requires another injection every 1-3
months
• does not protect against sexually transmitted
diseases including HIV/AIDS
8.6 Contraindications
•
lactating mothers less than 6 weeks post-partum
• current or past history of breast cancer
• current or past history of ischaemic
heart disease, severe hypertension, diabetes mellitus for than
20 years or associated with damage to vision, kidneys or nervous
system
• current deep vein thrombosis or pulmonary
embolism
• active viral hepatitis, severe cirrhosis,
benign or malignant liver tumors
Emergency Contraception should
be used as a ‘back up’ if more than 2 week late for
DMPA injection and more than 3 days late for combined monthly injection.
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