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Over the past weeks Implanon, the three-year contraceptive implant, has been in the media spotlight. It was reported that 12-year old Aboriginal girls were “temporarily sterilised” with Implanon in a number of Queensland and Northern Territory remote communities (see, for instance, Tim Dick in The Sydney Morning Herald, April 16, 2008).

This issue raises serious questions about health professionals aiding and abetting sex under the legal age of 16. It also reminds us that the law is often not enforced and males who have sex with underage girls get away without prosecution. However, other than reporting that some of these young girls were found with sexually transmitted infections (STIs), Implanon itself was not queried for its medical problems.

As Implanon is gaining widespread currency as the new “cool” contraceptive for young women everywhere in Australia, it warrants a closer look at what it is and what it does.

Implanon is a second generation progesterone-like contraceptive implant. Its ingredient Etonogestrel is very similar to the Depot progesterone in Depo Provera and Levonorgestrel in the discredited Norplant (which caused blindness in women and was taken off the US market in 2002 but is now making its comeback as Norplant-II in Europe).

Implanon consists of a 40mm single polymer rod that is injected under the skin in a girl’s/woman’s upper arm where it can be felt. It can migrate and may be hard to find if she wants to have the rod removed before its three-year effectiveness has run out. Health providers need to be instructed in both implantation and removal.

Implanon was approved in Australia in 2001 and has since become one of the most favoured contraceptive options by reproductive choice groups. In 45 years on: What now in Contraceptives?, a widely-distributed free booklet available in GP surgeries published in 2007 by the National Council of Women in Australia, Implanon is listed as the number one non-daily method.

Its advantages are described as:

• convenience - not having to remember to take anything;
• long duration of use;
• reliability; and
• fertility returns quickly upon removal of implant.

All points that may especially appeal to young girls and women who have grown up with the “one stop-quick-fix-no-bother” approach to life.

Indeed, featured in the booklet as “Being a busy girl …”, is Biana Dye, presenter of Nova radio, a station for the young. She is excited about Implanon: “What a cool concept not having to worry about contraception for three years.”

The only disadvantage the booklet includes is that the “menstrual cycle is altered and some women have irregular periods”.

Throughout the booklet, Implanon is then repeatedly mentioned as the latest exciting contraceptive choice. Unfortunately, underplaying risk and adverse effects does no service to girls and women. In June 2003, the TGA (Therapeutic Goods Administration) mentioned in their Adverse Drug Reactions Bulletin that they had received 130 adverse reaction reports, 37 of which related to prolonged bleeding between two and 26 weeks. (33 of the 37 women had their implant removed.) Other well known adverse effects, listed by the US FDA (Food and Drug Administration who only approved Implanon in July 2006) include “increased or decreased bleeding frequency including amenorrhea (no periods), headaches, acne and emotional lability [mood swings]”.

The problems don’t stop there. As with the three-month injection Depo Provera (also still widely administered to girls and women of all ethnicities) there is the serious problem of potential bone mineral density (BMD) loss. Because Implanon has only been on the market since 1998 (in Europe), it will be years before Implanon users will know whether the oestrogen decreasing mechanism of this synthetic progestin will significantly reduce BMD.

A 2007 study of the forearm bone density of 111 women, reported in Reproductive Health Vol 4, No 11, comparing levonorgestrel (Norplant) and etonogestrel (Implanon) is cause for concern. After 18 and 36 months of use, BMD of the “distal radius” of the forearm in both groups was “significantly lower” (Monteiro-Dantas et al.,) although the “ultra-distal radius” appeared not to be affected.

It needs to be remembered that it took from the mid 1980s to 2004 for the manufacturer of Depo Provera to finally acknowledge BMD loss from the three-month injectable drug and for the FDA to require them to put a black box-warning on the product.

A similar time span of almost 20 years would make it another 10 years (to 2018) before it will be known more conclusively whether Implanon leads to significant bone density loss. Like Depo Provera it may only be partially recovered once the contraceptive is stopped. In the meantime, thousand of users - including girls and young women who are most vulnerable to bone loss - may jeopardise their long-term health and risk higher levels of fractures from osteoporosis as they get older. And they’re not even told that this “cool” contraceptive may put them at risk.

In common with other progesterone-like contraceptives (including the mini pill) Implanon is not recommended for women who smoke and those with heart or liver disease and vaginal bleeding. Loss of libido during the use of Implanon is another frequent problem not mentioned by its enthusiastic promoters. So are problems with its removal. As one recent user remembers:

I had it implanted when I was 18 (I had really adverse reactions to the pill), and it has done something permanently to me - ever since I have had no sex drive at all. Must be something to do with hormone levels. I didn't get my period for the whole three years I had it in. Anyway, I had it implanted in (state), and when I wanted it out I couldn't find ANYONE who did it. I rang doctors, hospitals, family planning clinics, and they all knew how to put them in, but not take them out. So I thought I may as well wait until the three years was up and I was in (another state).

As girls and boys are subtly and not so subtly steered towards engaging in sex at a pre-teen age by various media messages, and, unfortunately as rape and sexual abuse are rife (and not just in Aboriginal communities), how to prevent a teen pregnancy becomes an important question.

In general, the popular understanding is that there is a whole cafeteria of safe contraceptive “choices” available and your doctor or family planning clinic will help you select the one “that’s best for you”. All hormonal contraceptives have side effects but at least if the pill makes you sick, you can discontinue it and look for something else. A plastic rod stuck in your arm is a different matter. Girls and women deserve to be told that Implanon may make them very sick and possibly reduce their bone density for good.

Dr Renate Klein, a biologist and social scientist, is a long-term health researcher and has written extensively on reproductive technologies and feminist theory. She is a former associate professor in Women's Studies at Deakin University in Melbourne, a founder of FINRRAGE (Feminist International Network of Resistance to Reproductive and Genetic Engineering) and an Advisory Board Member of Hands Off Our Ovaries.