By Laura Garrido BSc, MSc (embryologist).
Last Update: 11/05/2015

The incorrect insertion of Implanon, a new contraceptive implant, may be the cause of nearly 600 unplanned pregnancies.

A BBC News’ article entitled Implanon: 600 pregnancies despite contraceptive implant suggests that this failure may be due to an incorrect insertion of the implant. A total of 584 cases of unwanted pregnancy have occurred among women using this method of birth control. However, the advice from the Spanish and British health authorities is that women should not panic about the safety and the accuracy of Implanon as a method of birth control provided it is properly placed.

What is Implanon?

This contraceptive implant is a hormonal method which releases its active substance into the bloodstream, achieving thus its contraceptive effect. This active ingredient exerts its contraceptive action in two ways:

  • It prevents the release of an egg from the ovaries.
  • Produces changes in the cervix that hinder the entry of sperm into the uterus.

It is a small plastic rod (2mm wide and 4mm long), which is inserted under the skin of a woman’s arm the first day of her menstrual period. It can be used during a 3-5 years period. Since its insertion is subcutaneous, surgery is required. It consists of a very simple surgical procedure, but it should be performed by a healthcare professional. Although it is an extremely reliable method, no contraceptive method is totally accurate.

The British press has recently published an article showing an amount of nearly 600 unwanted pregnancies in women using this contraceptive method. Similarly, Channel 4 News has spoken about this as well as about the side effects that this method has been causing since its authorisation in 1999.

As for Spain, this implant was first sold in 2000, although it is not very popular yet –less than 1% of childbearing age women use it.

The British Government has releassed a reassuring message, since a large number of women in the UK are using this method and most of them are satisfied with the results. Currently, 800,000 women in UK use Implanon and nearly 1.4 million have been using it since its authorisation. As a result, less than 1,000 women became pregnant despite using this method.

On the other hand, the Spanish Health Ministry has spoken out on behalf of this information, reporting its intention to review the subject at forthcoming meetings with the Pharmacovigilance Inspectors Working Group. Ezequiel Pérez, spokesman for the Fundación Española de Contracepción, a panel whose aim is the scientific training on contraception, has also stated that this method is endorsed by several scientific studies and its failure may be due to its misuse instead of the method itself.

Importance of correct placement

The implant maker is MSD and its commercial name is Implanon. In October 2010, it was replaced with a new version called Nexplanon, which consists of a device designed to be inserted more easily. In addition, it includes a system which helps finding its location on imaging tests.

Following this article, manufacturer MSD has stated that the implant is both effective and safe. They have also remarked the importance of its correct insertion in order to guarantee its protection against an unwanted pregnancy as well as the fact that “no contraceptive is 100% effective”. In short, patients are recommended to go and get it seen in case there is any doubt.

Authors and contributors

 Laura Garrido
BSc, MSc
Embryologist
Bachelor's Degree in Biotechnology from the Pablo de Olavide University (UPO) of Seville, Spain. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI). Experience at IVF, andrology, and general analysis laboratories. Embryologist specialized in Assisted Reproduction. More information