The pill, birth control, contraception, contraceptive pill.

Better safe than sorry ... low fertility doesn't mean no fertility. Photo: Fiona-Lee Quimby

The fertility of women in their late 40s and even early 50s is significantly lower than that of women in their 20s, but contraception may still be needed. While the chance of a pregnancy for women over 50 is less than 1 per cent, for that one woman in a hundred an unintended and unexpected pregnancy can be very challenging. In my practice I see potentially fertile women who do not want to become pregnant at this later stage of life yet are not using contraception. While this is a calculated decision for some, others are surprised to learn they could fall pregnant. The media have rightly stressed the importance of not leaving it too late to start a family, but this may have resulted in some women underestimating their chances of becoming pregnant later on.

There are many methods of contraception available for 'mid-life' women. While the increasing chance of background health issues such as hypertension and diabetes can limit contraceptive options, the wide range of non-hormonal as well as hormonal alternatives mean that all women should be able to find a suitable method. For example, the combined oral contraceptive pill, containing oestrogen as well as a progestogen hormone, can be an appropriate choice for many women in their 40s and its benefits generally outweigh any health risks. As well as providing effective contraception, the combined pill also promotes bone health and counteracts 'perimenopausal' hot flushes and night sweats. 'The Pill' can also be helpful in managing heavy menstrual periods which result from fluctuating hormone levels at this stage of life. However, once a woman reaches 50 the health risks including deep vein thrombosis outweigh the benefits and switching to a method which does not contain oestrogen is advised.

Progestogen-only contraceptives can be used up to and beyond the age of 50 years.  These methods include the progestogen only pill (sometimes called the mini-pill), the contraceptive implant and the hormonal intrauterine device (IUD). The hormonal IUD releases the equivalent of two minipill's worth of progestogen each week into the uterus. It provides very effective contraception and is highly effective at reducing menstrual blood loss. Heavy periods, sometimes with flooding and the passage of blood clots, can be the result of serious causes such as uterine cancer and it is essential that these are ruled out before an IUD is inserted.

So how long does contraception need to be continued? Women frequently ask for a hormone test to check whether they have reached menopause but predicting the endpoint of fertility is not quite so simple. Even after many months of absent periods, the perimenopausal menstrual cycle can kick in again, occasionally for a few years! We therefore advise that women aged 50 or more can safely stop contraception only after they have experienced 12 months of absent periods, while women less than 50 are advised to wait for two years of no periods.

Women who are using a hormonal method of contraception may not 'know' whether they have reached menopause because of the effect on menopausal symptoms and signs. In this case we sometimes advise switching to condoms in order to assess what is happening to the woman's natural cycle or, in some specific instances, perform serial hormone tests to guide our advice. While the average age of menopause is 51 years in Australia, some women will continue to menstruate and remain potentially fertile until the age of 55!

At this point I would like to put in a good word for condoms. While they can seem off-putting prospect for some couples in a long term relationship, they are an 'essential' for women and men entering new relationships. Condoms are unique in having a dual role in preventing sexually transmissible infections such as Chlamydia as well as unintended pregnancy. Additional water-based lubricant can be useful to reduce the vaginal irritation that can occur at the perimenopause as well as minimise condom breakage.

The Emergency Contraceptive Pill (ECP) is another 'essential' when it comes to preventing pregnancy. It consists of a single dose of progestogen hormone, is available over the counter at the pharmacy and is effective up to five days after unprotected intercourse. The ECP is safe to use by women of all reproductive ages, including those at the very young and the not so young end of the fertile spectrum.

The decision about whether contraception is still necessary, as well as which type to use, is ultimately both individual and personal. It will be determined by the nature of the woman's relationship as well as her particular medical and social circumstances. One thing is certain, important decisions such as these should be backed up by factual information.

Dr Deborah Bateson is the Medical Director of Family Planning NSW.