Contraceptive choices: the hormonal methods

Posted on 28 November, 2018

How long has it been since you really thought about the contraception you’re using (or not using)?

Our bodies, relationships, reproductive plans, and lives change a lot over time so it’s really worth reviewing your method of contraception regularly.

This two-part series covers a variety of contraceptive methods currently available in Australia. In part one I’ll discuss the hormonal methods, and in part two the non-hormonal ones.

Efficacy rates quoted are calculated as a reduction in monthly probability of conception. A “normal” pregnancy rate for a healthy fertile couple not using contraception is considered to be 20% per month.

The Pill

This is often the first choice of adolescents and young women embarking on longer-term contraception (or “just to regulate my periods”) because of its long history, effectiveness… and because mum used it, of course!

“The pill” refers to combined oral contraceptive pills (COCP) containing both a synthetic estrogen and a progestogen to prevent ovulation. The “period” bleeding which occurs during the sugar pills at the end of each pack is simply in response to hormone withdrawal when the active pills are ceased. Advantages of the pill include the ability to predict and control menstrual bleeds (which are often lighter and less painful), very effective contraception when used correctly (up to 99.7% for “perfect” use but more like 91% for “actual” use) and possibly even improvement of your acne.

On the downside, estrogen-containing contraception such as the pill is unsuitable for women who have certain types of migraines, blood clotting disorders, liver problems, cardiovascular problems or breast cancer, or have recently given birth. And pay attention if you’re a smoker over the age of 35: get off the pill! Your risk of life-threatening blood clots is unacceptably high and increasing with age… you need to give up the fags or choose an estrogen-free contraceptive.

The pill’s effectiveness is reduced by some medications (although not most antibiotics, as we used to think), and by conditions which reduce gut absorption such as diarrhoea and vomiting. And of course it will never be a good choice if you can’t remember to take it every day.

There are new formulations with different progestogens and different numbers of pill-free days coming on the market all the time, so chat to your doctor about which might be the best for you. A problem with one pill doesn’t necessarily mean that another kind wouldn’t suit you.

Vaginal ring (Nuvaring)

This is a relatively recent addition to the market in Australia. Essentially it is a thin rubbery ring inserted into the vagina by the user which delivers estrogen and progestogen through the vaginal wall.

The ring is designed to remain in the vagina for three weeks, and then a few days after removal a “withdrawal” bleed occurs. A new ring is inserted after one ring-free week. Nuvaring is very similar in its pros and cons to the pill and is equally effective, although it may be a better choice for women who have difficulty remembering to take a pill every day or who have gut-absorption problems. It is quite expensive however, and should not be used by women who need to avoid estrogens (as for the COCP).

“Mini pill”

The “mini-pill” (progestogen-only pill, or POP) is the estrogen-free younger sister of “The Pill”. The progestogen causes thickening of the mucus at the cervix, which blocks sperm from entering the uterus. It needs to be taken within three hours of the same time every day for continued effect, and failure to do so requires use of another method or abstinence until after another three days of correct pill taking. If used properly however its effectiveness is roughly equal to COCPs.

POP is most suitable for women who are very reliable at remembering to take it, want or need to avoid estrogen, are breastfeeding, who are older or have low fertility. It is generally considered unsuitable for adolescents due to their high fertility and difficulty adhering to the strict dosing times.

DPMA injections

The depot medroxyprogesterone acetate, or DPMA injection is another progestogen-only method but because it comes in the form of a three-monthly injection it eliminates the need to remember daily pills. It is 94% effective, can make periods lighter (or even cease altogether) and does not have estrogen-related problems.

Disadvantages include unpredictable bleeding and a potentially long delay in fertility return of up to 12 months after the last injection, so avoid DPMA if you want to fall pregnant within a year. DPMA can also delay the achievement of peak bone density if used in younger girls for an extended period (although this seems to be reversible on cessation of use). Male injectable contraception is currently not available in Australia.

Implants

The progestogen-only implant currently available is called Implanon NXT. It is inserted into the skin on the inside of the non-dominant upper arm and releases progestogen in a measured way over three years. Similarly to DPMA, it prevents pregnancy mainly by preventing ovulation and causing thickening of the cervical mucus so that sperm cannot penetrate into the uterus.

This is a very effective form of contraception (99.9%) because it totally eliminates user-error problems during its three-year lifetime. It is a very popular and inexpensive choice for fertile teens (often initiated by their worried mums) due to its reliability, but the most common reason for early removal is an unwanted bleeding pattern; around 20-25% of users will end up with frequent, unpredictable (although usually light) bleeding. Others will find that they get no bleeding at all, which may or may not be agreeable to them, but it is impossible to predict in advance what an individual’s bleeding pattern will be… just expect it to be different.

Implanon is a great option for those who find it hard to take daily pills, can’t take estrogens or need highly effective, inexpensive contraception. It must be removed after 3 years however, as retention of an expired implant increase your risk of ectopic pregnancy.

IUDs

Intrauterine devices or (IUD’s) are usually T-shaped devices around 2cm long which are inserted into the uterus by a specially-trained doctor. They are designed to remain within the uterus for 5-10 years preventing pregnancies but can be easily removed at any time for a rapid return to baseline fertility. IUD’s are available in two main types in Australia: copper IUDs (which I’ll cover in Part Two: Non-Hormonal contraception) or the progestogen-containing intrauterine system (IUS) called Mirena.

Mirena

This has achieved almost cult-like popularity amongst mothers, and with good reason. It offers highly effective (99.8%) semi-permanent contraception without the surgical risks or recovery time of sterilisation.

You don’t need to remember pills every day, it’s safe in breastfeeding (as are all the progestogen-only methods), has a lower risk of side effects than other hormonal methods and it usually makes your menstrual bleeds either very light or non-existent; in fact Mirena is a widely-used treatment for heavy periods.

The stem of the IUS contains a progestogen which is delivered directly to the lining of the uterus. This acts locally to thin down the lining (making it unsuitable for pregnancy) and generate thick, sperm-blocking mucus. Its local delivery means that a much lower amount of progestogen passes into your bloodstream compared to other progestogen-based contraceptives.

Sounds great… so what’s the catch? Well, in years gone by IUD’s had a bad name because early models had design flaws which increased infection rates. These have now been ironed out but still the insertion procedure itself carries a small risk of uterine infection, which may then need to be treated with antibiotics.

There are also other small risks associated with IUDs, best explained in context by your doctor. And even those who love their IUD will admit that the insertion procedure is unpleasant. IUDs are most often recommended to women who’ve had babies because they tend to be a bit easier to insert and the procedure is generally better tolerated. However sometimes it is simply the best option for a woman who hasn’t had babies, and Mirena’s period-reducing effects have made it increasingly popularity with younger women too.

Some clinics can also insert IUDs under sedation. To get the best idea about whether an IUD might suit you book in for a consultation and examination by a doctor who does the procedure: some GPs can do this, or SHFPACT Canberra, Marie Stopes (Canberra), Gynaecology Centres Australia (Queanbeyan) or your gynaecologist.

Emergency contraception

Whilst not considered to be a form of everyday contraception as such, I wanted to mention the “morning after pill” here just to remind women that they do not have to live in fear of pregnancy for weeks after an episode of unprotected intercourse.

Emergency Contraception (EC) is usually 1 or 2 tablets of high dose progestogen (much higher than in the pill) which delays or prevents ovulation and makes the uterus unsuitable for pregnancy. It is 85% effective if administered within three days but evidence shows that it can be effective even up to 1 week after intercourse.

Tablets can be obtained without a script from pharmacies, Family Planning agencies and some health centres; do consider a doctor’s visit afterwards though to work out your best long-term contraceptive choice.

The copper IUD is also highly effective emergency contraception (98%) if inserted within five days of unprotected intercourse but you need to get quick access to a doctor who can insert it for you. Don’t forget to consider screening for STI’s after an episode of unprotected sex too, as EC won’t prevent infections.

For more information about these contraceptive methods click on the links throughout this post, chat to your doctor or sexual health care provider, or check out these resources from True and Marie Stopes to help you choose the best method for you.

Stay tuned for Part Two: Non-Hormonal Contraception coming soon!