Contraceptive Pill

Contraceptive pillsThe development of the oral contraceptive pill in 1959, and its widespread release in 1962, revolutionised the lives of modern women, and changed society as a whole forever. For the first time there was an effective, safe, reliable, easy to use, reversible contraceptive that did not interfere with lovemaking and had no aesthetic drawbacks.

The oral contraceptive pill is the safest and most effective form of reversible contraception. There are many different dosage forms and strengths, so that most women can find one that meets their needs. The main types are the monophasic (constant dose) two-hormone pill, the biphasic (two phase) and triphasic (three phase) hormone pills in which the hormone doses vary during the month, and the one hormone mini-pill.

The pill has several positive benefits besides almost perfect prevention of pregnancy. It regulates irregular periods, reduces menstrual pain and premenstrual tension, may increase the size of the breasts, reduces the severity of acne in some women, and libido (the desire for sex) is often increased. It even reduces the incidence of some types of cancer.

Two different hormones control the menstrual cycle. At the time of ovulation, the level of one hormone drops, and the other rises, triggering the egg’s release from the ovary. When the hormones revert to their previous level two weeks later, the lining of the uterus (womb) is no longer able to survive and breaks away, giving the woman a period.

The pill maintains a more constant hormone level, and thus prevents the release of the egg. In fact, it mimics the hormonal balance that is present during pregnancy, so the side effects of the pill are also those of pregnancy. The body, being fooled into thinking it is pregnant by the different hormone levels, does not allow further eggs to be released from the ovaries. With the triphasic pills, the level of both hormones rises at the normal time of ovulation, and then drops slightly thereafter to give a more natural hormonal cycle to the woman, while still preventing the release of an egg.

The hormones commonly used in contraceptive pills include ethinyloestradiol, levonorgestrel, norethisterone, gestodene, and mestranol. Other less commonly used hormones are the oestrogen ethynodiol diacetate and the progestogens norgestimate, desogestrel, drosperidone and norgestrel. There are some specialised types of contraceptive pills, which have added benefits such as the improvement of acne when the hormones cytoperone and ethinyloestradiol are combined.

When the pill is stopped (or the sugar pills started) at the end of the month, the sudden drop in hormone levels cause a hormone withdrawal bleed (period) to start.  If the woman stops taking the pill, her normal cycle should resume very quickly (sometimes immediately) and she is able to become pregnant.

If taken correctly, the pill is very effective as a contraceptive. But missing a pill, or suffering from diarrhoea or vomiting can have a very pregnant result. Some antibiotics can also interfere with the pill.  If any of these things occur, continue to take the pill but use another method of contraception until at least seven active pills (not the sugar ones taken when you have your period) have been taken.

In its early days there were some questions raised about the wisdom of long-term reliance on the pill, but a woman on today’s pill is taking a hormone dose that is only 4% the strength of the original. It is much safer to take the contraceptive pill for many years than it is to have one pregnancy, and that is the realistic basis on which to judge the safety of any contraceptive.

A few women do have unwanted side effects from the contraceptive pill. These can include headaches, break through bleeding, nausea, breast tenderness, increased appetite and mood changes. If these problems occur, they can be assessed by a doctor, and a pill containing a different balance of hormones can be prescribed. Rarely, a serious complication such as a blood clot in a vein may occur.

Although the contraceptive pill is very safe, there are some women who should not use it. Those who have had blood clots, severe liver disease, a stroke or bad migraines must not take the pill. Heavy smokers, obese women and those with diabetes must be observed closely, and probably should not use the pill after 35 years of age.

There is no need these days to take a break from the pill every year or so. This may have been the case in earlier years, but is no longer necessary. It is possible (and safe) to take the active pills of a monophasic (constant dose) contraceptive pill without a break for three months or more, then have a one week break when a period will occur. This way the woman will only have four periods a year, but some women have break through bleeds when attempting this.

In its most commonly used forms, the pill is a combination of the hormones oestrogen and progesterone. There is also a “mini pill” which contains only a progestogen hormone and is suitable for some women, including breastfeeding mothers, who cannot take the combined pill. The mini pill is less reliable than the combined pill and is more likely to give rise to irregular bleeding, but serious side effects are much less common. It is vital to take it at the same time each day.

The effects of the pill are readily reversible. If a woman decides to become pregnant, she could find herself in that state in as little as two weeks after ceasing the pill, with no adverse effects on the mother or child.

(Last modified: 26th Sep 2014)

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