How to take the pill safely

Combined contraceptive pills are made from two synthetic hormones. Because the hormones are in amounts that are not normal for the body they can have side effects as well as the desired contraceptive effect.

The main way the hormones provide contraception is to stop the ovary producing mature eggs each month making conception impossible. It requires seven days of pill taking to put the ovary to sleep and about seven days for the ovary to wake up again. For this reason lovemaking in the seven day pill free period is safe; there is not enough time for you to produce an egg before the next packet of pills starts to suppress your ovaries again. However, this is critically dependent on not missing or delaying pills towards the end or beginning of the packet—you only have one week's grace before your ovaries produce an egg. Do not make the pill free break any longer, even if you get a withdrawal bleed (period) on the normal day. If you miss one or more pills near the end or delay starting the next packet you are giving the ovary more than seven days to wake up and start producing a mature egg. This is more dangerous than missing pills in the middle of the pack. Because of this, if you miss a pill with less than seven pills left to the end of the packet, you should start the next packet without a break so that the ovary stays dormant. This is true for 21 pill packets; packs with 28 pills have seven dummy pills at the end of the packet that do not count. If you remember to take a missed pill within twelve hours of your normal time then it does not count as missed—any longer is too long and you should not consider yourself protected for the next seven days so avoid sex or use other, additional contraception. You should continue with the rest of the packet at the normal time.

Do not stop taking the pill if you have bleeding in the middle of the cycle. This is common when first starting the pill and usually settles. If it continues for more than two or three cycles you should see your doctor for a check-up.

If you have diarrhoea or vomiting, or take antibiotics, you may not absorb the pill from the gut. If these conditions apply, you cannot trust the pill for contraception and you should use an additional method such as a condom. Do not forget that it takes the ovary seven days to go to sleep again and so you should continue additional methods during and for seven days after antibiotics (or diarrhoea and vomiting).

How long can I take the pill for safely?

Because the pill suppresses the normal cycle of your female hormones you can continue taking a second or even third packet of pills without a break if it is important to delay your withdrawal bleed. For example you may wish to do this if you are going on holiday. However, taking every packet without a break is not safe because the womb depends on a bleed to discard its stimulated inner lining. If used responsibly, the pill does not increase your chances of cancer of the lining of the womb (in fact the risk of this cancer is reduced). However, it does not protect against cancer of the neck of the womb (the cervix) so you should have regular smears—every three years usually—to detect any changes before they become nasty. Incidentally, the pill makes cancer of the ovary much less likely. There is no conclusive evidence that breast cancer is more common in pill takers. However, if you have a close relative with breast cancer you should discuss this with your doctor.

There is no reason to have a break in pill taking every so often and particularly so if you run a risk of pregnancy by stopping your contraception. One in two women stopping the pill will become pregnant within 3 months (if they have sex without contraception of course). The pill does not damage your future fertility and if fully reversible. Unless you smoke, or have other risk factors for side effects that your doctor would enquire about, there is no reason why you should not continue taking the pill until the menopause if you wish.

Sexually transmitted diseases

One of the ways the pill provides contraception is by altering the quality of the mucus at the neck of the womb making it harder for sperm to get through. There is some benefit in reducing the chances of pelvic infection as well. However, this is not sufficient to protect you from sexually transmitted diseases. If you do not know your partner well you should use a condom for additional protection. Condoms will provide protection against viruses such as HIV which causes AIDS, and the viruses that cause cancer of the neck of the womb. It will also protect you against bacteria that can cause vaginal or internal pelvic disease. The latter can damage your fallopian tubes and reduce future fertility.

Important side effects

The pill does have side effects. The most important is the effect on blood clotting. This is not usually a problem but women who have already had clots in the large veins of the legs or lungs cannot safely take these types of pills. If you develop severe pain in the calf of one leg, severe, sharp pains in the chest, unexplained breathlessness or coughing of blood you should see your doctor. Additionally, if you have severe migraine headaches with symptoms such as weakness, pins and needles or numbness coming on during or after the headache, there is a risk of causing a stroke if you take the pill—you must stop the pill immediately. If you develop severe migraine after starting the pill you should tell your doctor. Migraine that is not particularly severe or has none of the extra symptoms mentioned above is OK. Any sudden loss of vision, speech disturbance, bad fainting attack or collapse should also be reported immediately.

You will have noticed that your doctor always checks your blood pressure before prescribing more pills. This is because the pill sometimes causes a rise in blood pressure that may be dangerous in the long term. Also the pill and high blood pressure in combination make heart disease and stroke more likely. For these reasons we will not give repeat prescriptions without seeing you in the surgery.

Smoking and taking the pill puts you at a much higher risk of heart disease and stroke. You should stop smoking if you wish to use the pill.

Some long term drugs reduce the effectiveness of the pill. Notable examples are anti-epileptics, some sleeping tablets, tranquillisers, and diuretics (water pills), and a few antibiotics such as anti-fungal or anti-TB drugs. You may require a change to a different brand of pill. Ask your doctor if you start any new drugs.

Occasionally the pill may cause jaundice (yellow discolouration of skin and eyes). You should report this to your doctor and stop the pill whilst the jaundice is investigated. There is a slight increased risk of developing gall stones in the early years of pill taking.

The pill is not 100% effective and occasionally pregnancies can occur despite meticulous pill taking. If you do become pregnant then stop the pill as soon as you know. There is no evidence that the pill causes harm to the developing baby.

Minor side effects that may be pill related

The pill does not normally cause thrush (candida infection). There are some women who have had more trouble with thrush after starting the pill; this may be for other reasons than taking the pill. The pill does not usually cause a vaginal discharge so if you have one tell your doctor.

The pill occasionally causes nausea at the beginning of the packet. This often settles after the first cycle but if it recurs you may try taking the pill at night or possibly switching to a lower dose pill. Do not forget that vomiting can interfere with pill absorption. Weight gain may be a problem for some. This is usually due to an increased appetite and responds to dieting. Occasionally a different brand of pill may help.

Women taking the pill have more episodes of cystitis. This may be a direct effect of the pill or an increased rate of "honeymoon cystitis". Make sure that you empty your bladder after sex to minimise this.

The pill does not cause epilepsy. Finally, there is a possibility that you become drunk more easily whilst taking the pill. The liver turns excess alcohol into waste products less efficiently when the contraceptive pill is being taken. You have been warned!

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