3 DECEMBER 2021 ausdoc . com . au
Therapy Update
Oral contraceptives
Women ’ s health
Dr Clare Boerma is a GP and the associate medical director at Family Planning NSW . Associate Professor Deborah Bateson is the medical director at Family Planning NSW , and is a clinical associate professor at the University of Sydney and an adjunct professor at UNSW Sydney and the University of Technology Sydney .
An update for GPs , including non-contraceptive indications , managing risks and side effects , newer agents and options for women across the reproductive lifespan .
ORAL contraceptives have been available in Australia for over 60 years , and despite the growing range of contraceptive choices , they remain the most popular method , being familiar , readily accessible and easy to start and stop . With perfect use , oral contraceptives are 99.5 % effective . However , with typical use , their efficacy can drop to 93 %, as a result of running out of pills , missed pills or drug interactions .
Combined oral contraceptive pills
Table 1 . Combined oral contraceptive pills available in Australia
Oestrogen dose ( micrograms )
Monophasic
Progestogen dose ( micrograms )
Brand name examples
Ethinylestradiol 20 |
Levonorgestrel 100 |
Femme-Tab ED 20 / 100 ,* Lenest |
|
|
20 ED , Loette , Microgynon 20 ED , |
|
|
Micronelle 20 ED |
Ethinylestradiol 30 |
Levonorgestrel 150 |
Eleanor 150 / 30 ED ,* Evelyn 150 / 30 ED ,* Femme-Tab 30 / 150 ED ,* Lenest 30 ED ,* Levlen ED ,* Microgynon 30 ED , Micronelle 30 ED ,* Monofeme ,* Nordette * |
84x ethinylestradiol 30 7x ethinylestradiol 10
84x levonorgestrel 150 -
Seasonique
( COCPs ) have evolved to include new hormonal constituents , reduced hormone doses and different pill regimens , resulting in improved safety and side-effect profiles , as well as additional non-contraceptive benefits .
By contrast , traditional progestogen-only pills ( POPs ) have remained relatively unchanged , until the recent introduction of a new drospirenone POP this year , which has a similar mechanism of action to COCPs in preventing ovulation .
Ethinylestradiol 50 Levonorgestrel 125 Microgynon 50 ED # 21 / 7 Ethinylestradiol 35 Norethisterone 500 Brevinor ,* Norimin * 21 / 7
Ethinylestradiol 35 Norethisterone 1000 Brevinor-1 ,* Norimin-1 ,* Pirmella * 21 / 7 Mestranol 50 Norethisterone 1000 Norinyl-1 # 21 / 7 Ethinylestradiol 30 Desogestrel 150 Madeline , Marvelon 21 / 7 Ethinylestradiol 30 Gestodene 75 Minulet 21 / 7
Ethinylestradiol 35 |
Cyproterone 2000 |
Chelsea-35 ED , Diane-35 ED , |
|
|
Estelle-35 ED , Jene-35 ED , |
|
|
Juliet-35 ED , Laila-35 ED |
Ethinylestradiol 20 Drospirenone 3000 Yaz 24 / 4 Ethinylestradiol 30 Drospirenone 3000 Petibelle , Yasmin 21 / 7 Ethinylestradiol 30 Dienogest 2000 Valette 21 / 7 Estradiol 1500 Nomegestrol 2500 Zoely 24 / 4 Triphasic
6x ethinylestradiol 30 5x ethinylestradiol 30 10x ethinylestradiol 40
Quadriphasic
2x estradiol valerate 3000 5x estradiol valerate 2000 17x estradiol valerate 2000 2x estradiol valerate 1000
* PBS-listed at time of writing
6x levonorgestrel 50 5x levonorgestrel 75 10x levonorgestrel 125
- 5x dienogest 2000 17 x dienogest 3000 -
#
Not recommended given unacceptable VTE risk
Logynon ED ,* Trifeme ,* Triphasil ,* Triquilar ED *
Pill pack ( hormone pills / hormone-free pills )
21 / 7
21 / 7
91 tablets / pack
21 / 7
21 / 7
Qlaira 26 / 2
This article reviews currently available COCPs and POPs in relation to their medical eligibility , side effects and non-contraceptive benefits , and provides guidance to support shared decision-making for patients who choose an oral contraceptive .
COMBINED ORAL CONTRACEPTIVE PILLS
COCPs contain both an oestrogen and progestogen , and primarily work by suppressing ovulation . Their efficacy is highly user-dependent , requiring daily pill-taking , with potential for reduced contraceptive effectiveness if a pill is taken over 24 hours late .
There are a range of pills available ( see table 1 ), varying by type and dose of hormones , whether the dose is uniform or changes through the cycle , and the number of hormone-free days per pack . Not all COCPs are PBS-subsidised , which may limit patient choice .
COCPs provide predictable hormone withdrawal bleeds and allow users to manipulate or skip withdrawal bleeds . In addition to providing contraception , COCPs can be useful for management of conditions such as acne , heavy menstrual bleeding ( HMB ) and dysmenorrhoea .
However , oestrogen-containing contraceptives are also associated with increased risk of VTE , ischaemic stroke and myocardial infarction , and have more contraindications than progestogen-only options . COCPs are associated with a reduced risk of ovarian , endometrial and bowel cancer and a small increase in the risk of cervical and possibly breast cancer .
Oestrogen component Ethinylestradiol ( EE ) has been the predominant oestrogen in COCPs because of its high oral bioavailability . Reduced EE doses in modern pills have simultaneously reduced their associated risks and side effects . COCPs with 50 µ g EE or mestranol are no longer recommended for contraception , including for patients using liver enzyme-inducing medications , because of an unacceptable associated VTE risk .
COCPs are considered low risk if they contain 35 µ g EE or less , and the risk of VTE and cardiovascular disease appears to be slightly lower with pills containing 20 µ g EE . However , the safety benefit with 20 µ g EE pills needs to be balanced against a higher likelihood of breakthrough bleeding , which may lead to early discontinuation .
In 2010 , COCPs containing estradiol ( Zoely ), an identical oestrogen to that produced by the ovaries , or its pro-drug , estradiol valerate ( Qlaira ), were introduced into Australia . While these have a lesser effect
NEED TO KNOW
Oral contraceptives have high efficacy when taken correctly and consistently ( 99.5 % for perfect use , 93 % for typical use ).
Combined oral contraceptives ( COCPs ) containing 30 µ g ethinylestradiol or less , with levonorgestrel , are considered first line because of their well-established safety profile .
COCPs can have additional non-contraceptive benefits for acne , heavy menstrual bleeding and premenstrual dysphoric disorder . There is generally limited evidence demonstrating superiority of one COCP type over another .
Extended use of COCPs allows users to avoid withdrawal bleeding , and potentially increases effectiveness and non-contraceptive benefits .
There is limited evidence guiding choice of progestogen-only pills ( POPs ). Traditional low-dose POPs have a three-hour missed pill window that typically limits their use .
A new 4mg drospirenone POP has recently become available that has a 24-hour missed pill window ( similar to COCPs ) and a four-day hormone-free break designed to reduce unscheduled bleeding .
on haemostatic and metabolic laboratory markers than EE , it remains unclear whether this will translate into lower risks of VTE and cardiovascular disease .
Progestogen component Levonorgestrel ( LNG ) and norethisterone ( NET ) have been used in COCPs since the 1960s . Since then , newer progestogens ( drospirenone , desogestrel , dienogest , cyproterone , gestodene and nomegestrol ) have been developed to reduce androgenic side effects and breakthrough bleeding .
While the small VTE risk associated with COCPs is predominantly linked to oestrogen , the type of progestogen may slightly modulate this risk . COCPs containing cyproterone , desogestrel , drospirenone or gestodene may carry a slightly higher VTE risk compared to pills containing LNG or NET ; however , the absolute risk remains low .
First-line COCP choice COCPs containing LNG with 30 µ g EE or less are useful first-line options as they carry the lowest VTE risk and are PBS-listed . Supporting informed choice of other pills will depend on patient preference , including the desire for non-contraceptive benefits , although it is important to be aware that head-to-head studies comparing different pill formulations for reasons other than contraception are limited .
COCP regimens Traditionally COCPs have had a seven-day hormone-free break to mimic a regular menstrual cycle , but the benefits of reducing or eliminating this break are now well established . Two COCPs are available with 24 hormone pills and four inactive pills , which may reduce risk of breakthrough ovulation if subsequent hormone pills are missed . Extended COCP use without a hormone-free break can avoid bleeding