The combined oral contraceptive pill ('the pill') first became available in Australia in 1961. While women's knowledge of reproduction and contraception has significantly improved since the pill's introduction many misconceptions about the pill still exist.
An inadequate knowledge of how the Pill prevents pregnancy and, therefore, how it needs to be taken, can put women at risk of unplanned pregnancy. It has been estimated that one in five unplanned pregnancies may be due to women's lack of knowledge about the pill (1). This article aims to provide an overview of how the pill works as well as dispel some of the common myths and misconceptions.
What do women know about the pill?
When women first visit a doctor to obtain the pill they are generally provided with information on how the medication is taken, risks/side effects and what to do if a pill is missed or its absorption is affected by diarrhoea or antibiotics.
The actual mechanisms by which the pill works to prevent pregnancy, however, are not always adequately covered by the doctor or, alternatively, understood by women. A study of 2 700 Pill users in Scotland, for example, revealed that almost one third of the respondents (incorrectly) believed the pill worked by killing all spermatozoa (2). Similarly, a study of university women found the measures taken following a missed pill placed them at risk of unplanned pregnancy (3). If women do not understand how the pill works, the rules about its use have little meaning and, therefore, are more likely to be overlooked or ignored.
How the pill works
The two hormones in the combined oral contraceptive pill, oestrogen and progestogen work on several levels to prevent pregnancy. Primarily, the pill works by stopping ovulation (the release of an egg from the ovary). If an egg is not released then of course conception cannot take place. As a back-up, the pill also makes the mucus released by the cervix thicker so the sperm cannot get through and thins the lining of the uterus so a fertilised egg has difficulty implanting.
When a woman takes the pill her normal menstrual cycle is interrupted. In effect, the pill tricks the body into believing it is pregnant. When the pill was being developed, however, it was felt that women would find the lack of a normal menstrual cycle disconcerting. Many women, for example, rely on their regular menstrual period for reassurance of not being pregnant. Consequently, it was decided to have the pill consist of 21 days of active pills (pills containing the hormones), followed by a pill-free interval of seven days (either no pills or sugar pills). The rapid decline in the artificial hormones which occurs in the pill-free interval results in a 'withdrawal bleed', which somewhat resembles a menstrual period and is often still referred to as a 'period' for simplicity. It is important, however, for women to understand that when they take the pill the bleeding which occurs during the pill free interval is not a menstrual period.
Similarly, women should be aware the current packaging of the pill (21 active pills, seven day pill free interval) was developed primarily for acceptability reasons and not because of any physiological reason. Indeed, contraception expert John Guillebaud explains, 'When you think about it we have here a bizarre contraceptive: one that we providers actually instruct the users not to use - for 25% of the time' (4). As Guillebaud suggests, the pill-free interval is the 'Achilles heel' of the Pill's efficacy as it can contribute to pill failure. To stop ovulation from occurring a woman needs to take seven consecutive active pills. In addition, if more than seven days are missed a woman risks ovulation and, if unprotected intercourse occurs, pregnancy. The lengthening of the pill free interval is one of the most common causes of pill failure and is often associated with a woman starting her new pill packet late. It is very easy to start a pill packet late with women either simply forgetting or not having their new packet with them.
Similarly, if some of the active pills near the end of the previous packet or active pills near the start of the new packet are either missed or not absorbed properly (due to vomiting, diarrhoea, use of antibiotics) this can also mean that there has not been enough pills taken overall to prevent ovulation. Women who miss pills towards the end of their packet often mistakenly believe it does not matter because they are having their 'period' soon. They do not realise that missing pills near the pill free interval may mean they have not taken enough pills to prevent ovulation in the next month. The most dangerous time to miss a pill is at the end or beginning of a packet (because it lengthens the pill free interval beyond seven days).
So why have a pill free interval?
As discussed above, the pill free interval was devised in the early days of the pill because it was felt that women would find having a 'period' more acceptable. Additionally, all the data on the safety of the pill was conducted using women who were having a pill free interval (5). If women did not have a pill free interval they would actually be taking more pills a year and, therefore, would be exposed to more of the hormones. For a range of reasons, however, women may choose to tricycle their pill (taking three packets together without a pill free interval), thus reducing the number of withdrawal bleeds a year from 12 to four.
Who could benefit from tricycling?
Women who suffer from headaches or migraines triggered by the sudden drop in hormones during the pill free week and women who experience heavy bleeding may benefit from tricycling. Tricycling is also often recommended for women with endometriosis as it reduces the number of painful withdrawal bleeds and the opportunities for retrograde menstruation (where blood travels in the wrong direction up the fallopian tubes and into the pelvis), thought to be one of the causes of endometriosis. For women who are debilitated by symptoms during the pill free interval, reducing the number of withdrawal bleeds can be extremely beneficial.
Tricycling or bicycling (taking two packets together with no pill free interval) can also be useful for women who wish to avoid the withdrawal bleed for special occasions like travel or a honeymoon.
It is important to note that for women taking a fixed dose pill (all the active pills in the packet are the same) tricycling simply involves taking several packets together without the pill free interval. However, when women are on a phasic pill (where there are two or three different types of active pills), simply running the packets together can result in break-through bleeding (although it will not reduce the efficacy of the contraception). Women taking a phasic pill, therefore, should ask their health care provider about how to tricycle.
Answers to other common myths surrounding the pill
The pill makes you fat
When the pill was first introduced it contained much higher levels of hormones than what is available in the formulations today (100-175 micrograms of oestrogen compared to 20-50 micrograms today). While weight gain was associated with these older high dose pills, the pill formulations used today do not always result in weight gain.
It is estimated that in the first year of use:
- 20-25% of women gain more than 2kg
- 60% of women experience no change or have a weight change within 2kg (both up and down)
- 15-20% of women actually lose more than 2kg weight (6).
The progestogen in the pill can increase appetite which may result in weight gain. Some women may also experience water retention but this can often be reduced by switching to a lower dose pill. Some brands of the pill are said to be more effective at reducing the symptoms of water retention.
You need to have regular breaks from the Pill
This is one of the most commonly held beliefs about the pill, even by some health professionals. The idea of taking a break from the pill may have its origins in the fact that the older pills consisted of high hormone doses. Some people also think it is necessary to have a break from the pill to maintain fertility levels. There is, however, no reason for women to take a break from the pill. Guillebaud suggests that in fact the repeated restarting of the pill 'might be more harmful than the relatively steady-state situation that is maintained during sustained use' (7). In addition, as side effects usually occur in the first few months of the pill's use, often subsiding after a time, women restarting the pill may experience these side effects again. It may be useful for women to remember that they are actually 'taking a break' during the pill free period.
The most dangerous time to miss a pill is in the middle of the packet
This myth seems to have come from the idea that ovulation occurs in the middle of a woman's menstrual cycle. However, women on the pill are no longer ovulating (even in ovulating women, ovulation does not necessarily take place in the middle of their cycle). When a woman has been taking active pills her ovaries will be in a resting state (ovulation cannot occur). She can miss seven active pills without the risk of ovulation (which is what occurs in the pill free interval). Therefore, the least dangerous time for a woman to miss pills is in the middle of the packet and the most dangerous time is at the beginning or end of a packet. See the pill and 'periods' section.
The Pill makes you infertile
This myth may stem from the fact that women using the pill as a form of contraception may delay childbearing until their late 30s, a time when their natural fertility has declined. When these women go off the pill and experience difficulty getting pregnant they think the pill has made them infertile when, in fact, the problem is age-related. In addition, a woman (or her partner) may have always had a fertility problem but it was never realised before because they were not trying to get pregnant (8). It may take a few months for cycles to return to normal for women who were on the pill.
It could be argued that being on the pill actually contributes to the preservation of women's fertility as it reduces the incidence of a number of conditions which impact on fertility (eg. ectopic pregnancies, endometriosis, fibroids) (9).
The Pill causes cancer
The pill actually provides a protective effect from cancer of the ovaries and cancer of the endometrium (the lining of the uterus). Women who take the combined oral contraceptive pill show an increased risk of cervical cancer but a direct causal link has not been established. It has been suggested that women who use the oral contraceptive pill may be less likely to use condoms with new sexual partners and, therefore, can be more at risk of being exposed to the genital human papilloma virus (which is considered to be the main contributing factor to cervical cancer). A 1996 review of data on the pill's use and breast cancer found there was a small increased risk of breast cancer in pill users, but this increased risk decreased after stopping use and after 10 years of discontinuation it had disappeared altogether (10).
Missed a pill?
Women's Health Queensland Wide's Health Information Line workers can provide the correct information to women who have missed a pill or whose pill/s may not have been absorbed properly due to vomiting/diarrhoea or medication (antibiotics). Women in Queensland can phone 3839 9988 or 1800 017 676 (toll free outside Brisbane) during week days. If a woman believes she may be at risk of an unplanned pregnancy she can use emergency contraception. Emergency contraception can be taken up to 72 hours after unprotected sex (but is most effective the earlier it is started). Emergency contraception is available over the counter at most pharmacies.
If you find it hard to take your pill at the same time every day
For women who commonly experience difficulties in remembering to take their pills at the right time or whose lifestyle makes it difficult (ie. regular international travel) and still wish to use a hormonal contraception, Depo Provera, Implanon or a Mirena may be good options. Depo Provera is a progestogen based contraception that is given as an injection every 12 weeks. Implanon consists of a small rod that is inserted under the skin in the upper arm. It releases small amounts of progestogen and lasts for up to three years. Mirena is a type of intrauterine device (IUD) that releases small amounts of progestin hormone and lasts for up to five years. For more information on these and other contraception options contact our Health Information Line (see above).
- Little, P et al. Effect of educational leaflets and questions on knowledge of contraception in women taking the combined contraceptive pill: randomised controlled trial BMJ 1998;316:1948-1952.
- Rajasekar D & Bigrigg, A. Pill knowledge amongst oral contraceptive users in family planning clinics in Scotland: facts, myths and fantasies Eur J Contracept Reprod Health Care 2000;5:85-90.
- Fletcher P C, Bryden P J and Bonin, E. Preliminary examination of oral contraceptive use among university aged-females Contraception 2001;63:229-233.
- Guillebaud, J. Contraception Your Questions Answered (3rd edition) London: Churchill Livingstone 1999;103.
- Guillebaud Ibid;112.
- Szarewski, A and Guillabaud, J. Contraception: A User's Guide (3rd edition) Oxford University Press: Oxford 2000;239.
- Guillebaud Ibid;255.
- Szarewski, A and Guillabaud, J;30.
- Guillebaud Ibid;139.
- Guillebaud Ibid;145-151.
Last updated: September 2008
© Women's Health Queensland Wide Inc. This article was written by Kirsten Braun and reviewed by the Editorial Committee for Health Journey, Vol III 2003. Minor modifications were made to this online version in September 2008.
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