Sexual health experts answer GPs questions about contraception

How effective is the Mirena for PMDD when compared with the pill?

The short answer is ‘not very’. This is because though the woman may not be bleeding or be able to easily recognise the stages of her cycle, she is still producing exactly the same hormones as she would if the Mirena was not in place.

There are a few strategies in PMS management which have some evidence to support their use. These include the use of 600-1200 mg of calcium daily, the daily use of a herb called Vitex Agnus-Castus (VAC), or the use of an oral contraceptive pill or contraceptive implant which suppresses the normal hormonal fluctuations occurring in a reproductive cycle and provides more stable hormone levels. Another option which is backed by good evidence is the use of an SSRI. These are often used at doses significantly lower than would normally be used to treat depression and in some women it may be necessary to only use the SSRI in the latter half of the cycle rather than daily.

One problem is that women with PMS are often more sensitive to synthetic hormones generally. You can sometimes take someone who gets quite severe symptoms for half of their cycle to someone who gets troublesome but less severe symptoms for the whole of their cycle on the chosen COCP. That is not a great trade as far as I’m concerned, and it may take several attempts before the best COCP preparation is found – if ever. It is also possible to combine a COCP and an SSRI as a dual treatment strategy.

~ Answered by Dr Terri Foran – Sexual Health Physician; Conjoint Senior Lecturer, School of Women’s and Children’s Health, UNSW.

How do you manage consultations about contraception with adolescents and their parents, especially when a parent thinks they know what’s best?

These consultations can be challenging, especially when parents are anxious or believe they know what the best option is.

Taking a structured approach to your consultation can help establish you as the expert. Educate the patient and parent as you go along to help them understand why you are making certain recommendations.

Before getting railroaded into talking about pills, make sure you take menstrual, medical and family histories. Check the patient’s BP and BMI, look for acne or hirsutism, and consider whether they need any investigations, such as thyroid or iron studies, coags or von Willebrand factor.

Consider a HEEADSSS assessment and try to get some time alone with the patient, because you’ll want to know if they are sexually active, but it may not be something they want to mention in front of mum.

Discuss the benefits, risks and side effects of different options. If they present with heavy menstrual bleeding and dysmenorrhea, combined oral contraception or nonsteroidals such as mefenamic acid or naproxen may be appropriate. The combined oral contraceptive pill can be tri-cycled or used continuously to minimise withdrawal bleeds. This is safe and recommended for managing heavy menstrual bleeding.

If they request a pill containing cyproterone acetate such as Diane, you can explain that the risk of developing a blood clot is a bit higher and that the guidelines therefore recommend starting with a levonorgestrel or norethisterone pill. You might also want to introduce the idea of a progesterone IUD for managing her down the track.

If the combined pill is suitable for her and they insist on using Diane, it is appropriate to review her within six months to check how her symptoms have responded.

At that point, if she is well-managed on the pill you can reiterate your original recommendations and suggest they might want to think about changing pills. If symptoms are not adequately managed, consider a gynae referral, because up to 70% of adolescents who do not respond to medical management for heavy menstrual bleeding will later be diagnosed with endometriosis.

~ Answered by Dr Sarah Callister – General Practitioner; Senior Medical Educator and Medical Officer, Family Planning Australia

What are the risks of breast cancer in women using LARCs compared with the combined pill?

A study from 1996 found there was a relative risk of 1.24 for current users of the combined pill but that study did not enrol sufficient numbers of those using other hormonal methods to determine risks for these. We now have larger numbers from the Oxford Population Epidemiology Unit publication from March 2023.

This group came out with much the same figure for the oral contraceptive pill: a relative increase of 23%. They also suggested that the increased risk with the progestogen-only pills is 26%, with the injectable progestogen 25%, and with the Mirena 32%.

Some of these findings are hard to explain from a first principles perspective – the high risk for Mirena does seem somewhat counter-intuitive for instance given the lower levels of circulating hormones when compared even to an LNG pill. When this happens, I always wonder about prescriber bias – however while such studies can be tricky in terms of making reliable comparisons, it does perhaps send a signal that perhaps there is something there.

The bottom line is that I don’t really like relative risk all that much because it overstates the real-world risks for our patients. The background risk of breast cancer is small for most women in the age group to which we are prescribing any of these contraceptives. So if you increase the risk by 20-30% it is still a small risk. The figure I like to use with my own patients is that if we were to look at all women using hormonal contraception methods, an extra three in 1000 may develop a breast cancer by the age of 55 that they otherwise would not have developed. It is a small risk, but it needs to be acknowledged as a possibility until we get more information for all hormonal methods of contraception.

~ Answered by Dr Terri Foran

How do different forms of contraception affect AMH levels?

Women sometimes ask about anti-mullerian hormone (AMH) testing in relation to ovarian reserve and their fertility plans. A large, cross sectional 2021 US study evaluated the effects of current contraceptive methods on AMH levels. It showed that women using a combined oral contraceptive pill, an implant or a vaginal ring had an approximately 23% reduction in their AMH levels compared to non-users.

Women who were using the progesterone-only pill had smaller differences in AMH levels, but it was still significant at around a 15% reduction. Even women who were using a levonorgestrel IUD, a Mirena, had about a 7% reduction in their AMH levels, although the authors questioned whether that was significant. Also, the longer the IUD had been in place the less the effect was on the AMH level.

This means we do need to consider the type of contraception someone is using when we’re discussing AMH testing. It is thought to probably take about two to three months for the AMH level to return to baseline after stopping hormonal contraception, so we need to carefully weigh up, with the woman, the risks of an unintended pregnancy if she is going to stop contraception to have AMH testing performed.

~ Answered by Dr Rebecca South – Women’s Health General Practitioner, Clinical Lead at Inner West Women’s Health

What is the best option for emergency contraception in a woman with a BMI over 30?

I think it is now generally accepted that overweight or obesity can impact the effectiveness of emergency contraception – particularly LNG emergency contraception.
With a less than 1% failure rate, a copper IUD is definitely the most effective emergency contraction method available for any woman, and where overweight compromises the effectiveness of oral ECPs, this is perhaps an even more important consideration. However, it can be very difficult to find someone to insert a copper IUD as an emergency procedure. Since copper IUDs are not PBS-subsidised cost may also be an issue.

The next best ECP method is ulipristal acetate, which is generally a bit more effective than the LNG ECP both in terms of its actual effect and the fact that it can be taken for up to five days after the act of unprotected intercourse. However, when you are considering a woman who is overweight, even ulipristal acetate begins to lose its efficacy once you get beyond about 88 kg.

Unfortunately, the efficacy of levonorgestrel emergency contraception tends to reduce beyond the 70 kg mark making it the third-best choice in this situation. So we all need to discuss the implications of the relationship of weight to ECP failure rates in our overweight patients and if it does let them down a woman should know that they can always come back and discuss their options.

See the FSRH Clinical Guideline: Emergency Contraception for more information, including a helpful flow chart.

~ Answered by Dr Terri Foran