1) Adapted from Prescribing Oral Contraceptives, Current Therapeutics, April 1995 by Dr Edith Weisberg (Family Planning NSW Ashfield, Sydney, New South Wales)

  What is an oral contraceptives?  

There are a number of different types of oral contraceptives. When women talk about the pill, they generally mean what is technically known as the combined oral contraceptive pill. The pill contains oestrogen and progestogen, two chemical substances which are very similar to the hormones that are produced by the ovary during the menstrual cycle.

In prescribing OCs it is essential that a practitioner spends time addressing  areas of uncertainty of concern, ensuring that the patients clearly informed about how the contraceptive works and what is needed to use it effectively. Patients also need to be informed of the likely initial adverse effects and what to do if a pills missed.

            Combined oral contraceptives

Ø          Introduction  

The Combined Oral Contraceptive (OC) pill is the most popular method contraception yet developed. It is estimated that approximately 65 million women throughout the world use OCs.

The formulations in use today are very different from the original pillfirst trialled in Puerto Rico in 1956. The dose of oestrogen had been reduced by 80% while the dose of progestogen has been reduced by 90%. This reduction in hormone dose has improved in tolerability so that modern combined OCs has very few adverse effects, the major one being breakthrough bleeding.

Ø          How good the pills preventing pregnancy

The pill is very effective if it been taken correctly. When taken according to instructions, at about the same time everyday, about 5 women out of every 1000 who take the pill for a year will become pregnant. In actual practice, the pregnancy rate for the pill is much higher: between 2 and 6 women in every 100 become pregnant.

Ø          How the pills work? 

 When the combined pill taken everyday, it prevent the body producing the hormones which normally stimulate the ovary to release an egg. This means that there is no eggs are released. As well as this, the progestogen of the pill makes the lining of the womb thinner. So that, it will become unsuitable for pregnancy. The progestogen also thickens the mucus produced by the glands in the neck of the womb (cervix) so that it is harder for the sperm to get through. This three actions make the combined pill the most reliable reversible method of contraception available at present.

Ø          The expectation  after taking the first pill 

With the modern low dose pills, the most common side effect  occurring in the first month  or two pills taking will cause  bleeding i.e. bleeding between periods. This usually settles down by the second or third cycle. If it is not settled by the third cycle, it is an indication that the need a different pill. Besides that, the period are usually lighter, shorter, and less painful than previously. This is one of the benefits of taking the pill. Breast tenderness initially some breast enlargement will be noticed.. Occasionally, a women is sensitive to oestrogen and may develop nausea even on low dose. This usually settles down after a few days.

If it does not, it may be necessary to change to a pill with a lower oestrogen dose or to use the progestogen only- pill.

                                                   LOW DOSE PILL

The original oral contraceptive pills tested in the 50s had 150µg of oestrogen and 10000µg

Of progestrogen. Today’s low dose pill contain between 20 and 35µg of oestrogen and between 125 and 1000µg of progestogen, depending on the type of progestogen used.

This mean that the modern low dose pill contains about one-fifth to one-tenth the dose of hormones originally used. As the dose has been reduced, the minor and serious side effects that can go with the high doses have also been lessened.

THE PROGESTOGEN ONLY PILL

  Introduction

The progestogen-only pill or mini pill contains very small amounts of progestogen.

It doesn’t contain oestrogen, which is found in combined oral contraceptive pills. The progestogen-only pill is called mini pill because it contains a much lower dose of progestogen, about one-third to one-fifth of the dose in combined pill.

Mode of action

The progestogen only pill’s main effect is on the cervical mucus, making the mucus thicker which makes it very difficult for the sperm to get through to fertilise the egg.

It also has an effect on the womb’s lining, making it unsuitable for pregnancy.

It is slightly less reliable than the combined pill, but still a very effective method of birth control.

Times for the pill taken

The progestogen-only pill is taken at the same time every single day. When one packed is finished, start the next packet without a break. Because the effect of cervical mucus  is at its best three hours after taking the pill, and start to diminish 21 hours after taking it, it is not advisable to take the Progestogen-only pill just prior to having intercourse. If  having sex mainly at night, or in the morning, it is best to take the pill with main evening meal, or in the middle of the day.

Expectation when first take the pill

It is hard to predict what will happen to the periods when start taking the progestogen-only pill. Women will have completely regular cycles, cycles longer than 4 weeks or shorter than 4 weeks, irregular cycles or nuisance spotting. Occasionally  women on the progestogen-only pill do not have periods at all. If they do not have period for 6 weeks, they are adviced to see for the doctor.

Women may noticed other minor adverse effects such s breast tenderness or enlargement. If these persist, they should tell their doctor.

The main risk of the pill

The progestogen-only pill contains no oestrogen. So, it has fewer adverse effects on body than the combined pill. It can be used by some women unable to take the combined pills. The combined pill has been shown to increase the possibility of developing a stroke, blood clot or heart attack ; it is unlikely that proestogen-only pills would increase this risk.

Progestogen-only pills may increase the risk of an ectopic pregnancy, if pregnancy occurs when taking the pill. Functional ovarian cysts may occur more frequently in women taking the progestogen-only pill.

Women who should not take the progestogen-only pill

ü      Having malabsorption  syndrome ,that is have difficulty of having absorbing food from the upper digestive tract.

ü      Having severe chronic liver disease

ü      Women who have previously had an ectopic pregnancy should probably also avoid the progestogen-only pills.

   More about progestogen only-pill

Ø      Certain drugs such as rifampicin and griseofulvin are known to reduce the effectiveness of the combined OCs and may also affect the progestogen-only pill. Therefore, women are advised to use another method of contraception (e.g. condoms) while they are taking these drugs.

Ø      The progestogen-only pill does not cause the infertility, and does not produce a delay in the risk of fertility after stopping the pill.

Ø      The progestogen-only pill can be taken during breast-feeding, as it does not reduce the volume of milk, and only a small amount is transferred in the milk to the baby.

Ø       The main risk of the pill

The pill’s main risk are the possibility of developing a stroke or a blood clot, or having a heart attack. The risk apply only while a women is taking the pill. The risk of heart attack is not increased for women who take the pill compared to women who do not take it, unless they also smoke. The risk of heart attack is increased with increasing age. For women who smoke. Therefore women over 35 years old who are smokers should not take the pill. All women contemplating taking the pill should try to stop smoking. The risk of having a heart attack or stroke while on the pill is increased by :

If a women has the more risk factors, she is the more to develop a heart attack or stroke while taking the pill. For women who has such risk factors, a possible alternative which does not appear to carry the risk of heart attack or stroke, is the progestogen only-pill or ‘mini pill’.

Ø          Women who should not take the pill

  Have had a heart attack or stroke in the past

ü      Suffer from focal migraine, that is loss of part of the sight in one eye, numbness of 

        one sight of the body, followed by migraine headaches.

ü      Have ever had breast or liver cancer

ü      Have certain congenital liver disorders such as Dubin Johnson or Rotor Syndrome

ü      Have had jaundice during a previous pregnancy

ü      Have severe liver damage

ü      Other diseases which may make it inadvisable to use the pill are:

·        Crohn’s disease

·        Epilepsy

·        Tuberculosis

·        Diabetes

Ø          More about combined oral contraceptives

Pill and menopause

The pill will not change the time at which menopause occurs, which is usually around 50 years of age. Taking the pill, however, will mean that the woman will not know when she has had her last period; while she continues to take the pill, she will have an artificial period once every 4 weeks. If they choose to continue to use the pill over the age of 50, the only way to know whether they have had last their period is to stop using it and have a blood test to check the hormone levels, to see whether they have actually achieved the menopause. If the test shows that they are not nearing the menopause, they can go back to taking the pill for another six months, and do the same thing again.

If they do not have a period for 6 months after stopping the pill, they can assume they have passed the menopause (the last period).

Pill and women over the age 40

If they are satisfied with the pill, are taking a low dose formulation, and provided them have no risk factors for heart disease and do not smoke, they can continue taking the pill until the menopause, which is usually occurs around the age of about 50.

Are there any advantages for older women to take the pill?

Many women in their 40s starts having problems with heavier periods or a shortening cycle. For these women, taking the pill will help them control their bleeding problems and also provide protection against cancer of the womb and ovary for at least 10 years after stopping the pill, at a time when the risk is much greater than for younger women.

Pregnant after stopping the pill?

The only information about how long it takes women to fall pregnant after stopping the pill comes from old studies relating to high dose pills. They suggested that there might be a lag of few months in the time it took women who had never had children to conceive after stopping the pill, compared to women who had never used the pill. With the modern low dose pill, however, it seems likely that there will be no delay in becoming pregnant. The old studies shows that at least 17% of women become pregnant the first month after stopping the pill. This compares with the general population in which 25% of couples produce the pregnancy the first month they try. After 6 months of trying, about 70% are pregnant.

It seems likely that the average couple will take more than one month to get pregnant after stopping the pill; most will get pregnant within six months.

      Oral contraceptives formulation

There are many types of  oral contraceptives in the market now to ensure that there  are pills suitable for each individual women. With the number of different pills available, it is unlikely that a women will be unable to find one that suitable to her.

A wide variety of OCs is available (table 1) with a variety of oestrogen doses combined differing  progestogens (table II). There are also different regimens :

ü      Monophasic formulations- Each active tablet contains a constant dose of

                                            oestrogen  and progestogen throughout the cycle.

ü      Biphasic formulations-  The dose of oestrogen is constant throughout the active

                                        tablets but the dose of progestogen is increased in the

                                        second half of the cycle.

ü      Triphasic formulations- the dose of oestrogen is increased  in the middle of the.

                                        cycle to lower the rate of breakthrough bleeding, whilst 

                                        the progestogen dose is low initially and is increased

                                        throughout the cycle

ü      Progestogen-only formulations- Contains no oestrogen and a much lower dose of

                                                   progestogen than the combined pill  about one-

                                                   third to one-fifth of the dose. It is taken everyday 

                                                   without a break.

        Choice of oral contraceptives formulations

The large range of combined OC formulations on the market means that it is possible for the majority of women to find a commercially available pill which suits their particular needs.

The UK National Association of Family Planning doctors recommend that the pill of choice for an individual should be the one containing the lowest available dose of oestrogen and progestogen which provides effective contraception, produce acceptable cycle control, is well tolerated, and has the least known effect on carbohydrate or lipid metabolism and haemostatic parameters. Combined OCs containing the new third-generation  progestogens (desogestrel and gestodene) are considered to be an improvement since they have no effect on lipid or carbohydrate metabolism. However there are no studies of their effects on cardiovascular disease that provide long-term clinical evidence that they are superior to the earlier low-dose OCs in practice.