Contraceptive Implants

Implants are small capsules which are placed under the woman’s skin. They release hormones into the bloodstream which prevent pregnancy.

The main implant to have been tested to any extent is NORPLANT. These capsules release the progestogen, levonorgestrel. Under a local anaesthetic, six small capsules of sealed silastic tubing are placed in a fan shape under the skin on the woman’s arm. The operation requires a 3 mm incision, and takes only five to ten minutes. Once in place, these capsules protect against pregnancy for at least five years; the failure rate is 0.5 per 100 woman/years. The capsules require no attention until the end of the five years, when they are removed; removal may take up to twenty minutes, depending on the amount of fibrous tissue that has grown around them. If the patient wants the contraceptive reversed before the five-year period is up, the capsules are simply removed early; fertility returns ‘without delay’, according to the reports published so far.

The capsules work like other progestogen-only contraceptives; they suppress ovulation in some cycles, thicken the cervical mucus to make it virtually impenetrable to sperm, and possibly alter the endometrium to prevent implantation. Because of this last factor, they should be subjected by the Christian to the same careful consideration as other progestogen-only contraceptives.

Disadvantages

The most common side-effect is menstrual disruption, which is the most frequent reason for discontinuing the method. The disruption may be heavy periods, prolonged periods, or spotting between periods. For ten per cent of women using NORPLANT, the average is 77 days of menstrual bleeding per year— about six days per period. This average does tend to decrease as the contraceptive is used for longer, so does not seem to lead to anaemia through excessive blood loss. Other reported side-effects can include headache (fairly frequent) and depression, loss of libido, irritability, loss of appetite, nervousness and dizziness (less frequently).

Through the five years of use, the dosage of progestogen is around 30mg per day — well below the level used in combined contraceptive pills, and more equivalent to the dosage of the mini-pill. However, recent research has suggested that the use of norgestrels such as levonorgestrel in progestogen-only contraceptives may in the long term contribute to problems of the cardiovascular system. Another area of concern is the suspected link between progestogen-only contraceptives and ectopic pregnancy; the Progestaserte IUD has been specifically linked with ectopic pregnancies by the USA’s Federal Drugs Administration. Both of these areas of concern are still being investigated, and may turn out to be drawbacks of this method for some or all women.