The contraceptive implant is a small flexible tube that is inserted into the upper arm. It releases progesterone into the systemic circulation over a long period of time.
Currently, Nexplanon® is the only contraceptive prescribed in the UK. It is easier to insert compared to previous models and contains barium, making it visible on X-ray. The implant has been shown to be more than 99% effective in providing up to 3 years of birth control.
In this article, we shall look at the procedure, indications and contraindications of the contraceptive implant.
Procedure
The contraceptive implant is a small, flexible 40mm plastic rod fitted by a trained healthcare professional, usually a doctor or a nurse.
The procedure is usually scheduled within the first 5 days of the menstrual cycle, and is effective immediately. If inserted after that window, it takes 7 days before it becomes effective, and alternative methods of contraception are advised during this time.
Insertion of the implant is classed as minor surgery. A local anaesthetic is administered to the skin of the upper arm. A metal device (known as an introducer), is used to pierce the skin and position the implant sub-dermally.
Fig 1 – Insertion of the Contraceptive Implant. (A) The implant introducer device. (B) The implant positioned underneath the skin.
Indications
The implant is indicated for use as contraceptive device only.
Contraindications
The major contraindications of the contraceptive implant are similar to the other progesterone only contraceptives. The following are the most common, but this is not an exhaustive list:
- Already pregnant
- Taking certain medications. Some enzyme-inducing drugs may make the implant less effective – e.g. medications used in HIV, tuberculosis, epilepsy and the herbal remedy St John’s Wort.
- Women with a history or current status of the following:
- Arterial disease, history of stroke or serious heart disease.
- Liver disease
- Breast cancer
- Unexplained vaginal bleeding
Advantages and Disadvantages
It is important to fully counsel the woman about the advantages and disadvantages of the contraceptive implant:
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