Hormonal contraception Q&As
Published by Bupa's health information team, November 2008.
Answers to questions about hormonal contraception
This section contains answers to common questions about this topic. Questions have been suggested by health professionals, website feedback and requests via email.
- What is the risk of getting deep vein thrombosis (DVT) from the contraceptive pill?
- At what age should I stop taking the contraceptive pill?
- Are there any medicines that can stop the contraceptive pill from working properly?
- What should I do if I'm sick after taking my pill?
- Can I take the pill so I don't have a period while I'm on holiday?
What is the risk of getting deep vein thrombosis (DVT) from the contraceptive pill?
The contraceptive pill does increase the risk of having a blood clot (deep vein thrombosis, or DVT). However, in most women this is still a very low risk, and certainly lower than the risk of blood clots associated with pregnancy.
Explanation
Taking a contraceptive pill slightly increases your risk of DVT - a blood clot in one of the deep veins, usually in the leg.
It's not possible to say precisely what your personal chances of getting a clot are. It's thought that about five women out of every 100,000 who aren't taking the pill get blood clots in a year. This is a low risk.
Some contraceptive pills contain newer types of progestogen called 'second generation' (eg levonorgestrel), and others contain 'third generation' progestogens (eg gestodene, desogestrel) which were developed even later.
The risk of DVT varies depending on what type of progestogens the pill contains.
For every 100,000 women:
- 15 per year will develop DVT if they are taking a contraceptive pill that contains second generation progestogens
- 25 per year will develop DVT if they are taking a contraceptive pill that contains third generation progestogens
This is still much lower than the risk of developing a blood clot if you are pregnant - 60 per year out of every 100,000 pregnant women.
If you fly while taking the contraceptive pill, this may also increase your risk of developing DVT. Speak to your GP, family planning nurse or pharmacist for more advice.
Sources
- Joint Formulary Committee, British National Formulary. 55th ed. London: British Medical Association and Royal Pharmaceutical Society of Great Britain, 2008
At what age should I stop taking the contraceptive pill?
This will depend on which type of contraceptive pill you're taking. It will also be different if you smoke, if you are overweight or have certain medical conditions such as diabetes.
Explanation
The risks associated with taking the contraceptive pill go up as you get older. However, these risks are also affected by other things such as smoking, obesity or having high blood pressure or diabetes.
The age at which you are advised to stop taking the contraceptive pill will depend on the type of pill you are taking and other lifestyle factors. For example if you smoke, you are likely to be advised to stop taking the contraceptive pill earlier than someone who doesn't. The more you smoke, the younger you will be when you're advised to stop.
Your GP or family planning nurse can give you information about the balance of benefits and risks of the contraceptive pill as you get older. He or she can also discuss possible alternatives with you, including the progestogen-only pill, an intra-uterine device (IUD or coil) or a contraceptive injection such as Depo-Provera.
Sources
- Monga A, editor. Gynaecology by ten teachers. 18th ed. London: Hodder Arnold, 2006:62-63
- Joint Formulary Committee, British National Formulary. 55th ed. London: British Medical Association and Royal Pharmaceutical Society of Great Britain, 2008: 428-429
Are there any medicines that can stop the contraceptive pill from working properly?
Medicines for epilepsy, antibiotics and several other types of medicine, including St John's wort can stop your contraceptive pill from working effectively.
Explanation
Always tell your GP that you are taking the contraceptive pill before you start taking any new medicine. Some prescription medicines and over-the-counter products such as St John's wort can make the contraceptive pill work less effectively.
If you take anti-epileptic medicines such as carbamazepine (eg Tegretol), the standard contraceptive pill or progestogen-only pill may not work for you and an alternative method of contraception might be more suitable.
If you are prescribed a short course of another medicine that interferes with the effectiveness of the contraceptive pill (such as antiviral and antifungal medicines), you may need a higher strength version of the pill, or need to use an alternative method of contraception. The antibiotics rifampicin and rifabutin, used to treat tuberculosis (TB) and other infections, are almost certain to stop the contraceptive pill working. You will need to use an alternative contraception method if you take one of these medicines.
The contraceptive effect of the pill may also be reduced by a course of antibiotics. You should use additional methods of contraception, such as a condom, while you are taking a short course of antibiotics and for seven days afterwards. If these seven days go into what would usually be your pill-free/inactive pill period, start the next packet straight away. If you are unsure, speak to your GP, family planning nurse or pharmacist.
Sources
- Joint Formulary Committee, British National Formulary. 55th ed. London: British Medical Association and Royal Pharmaceutical Society of Great Britain, 2008:; 428-429
What should I do if I'm sick after taking my pill?
The effect of the contraceptive pill may be lost if you vomit or have diarrhoea.
Explanation
If you are sick within two hours of taking your combined contraceptive pill, take another one as soon as possible. If you are vomiting or have diarrhoea for more than 24 hours, you should use additional contraceptive precautions (such as condoms) for seven days. If these seven days go into what would usually be your pill-free/inactive pill period, start the next packet straight away. If you are unsure, speak to your GP, family planning nurse or pharmacist.
Sources
- Joint Formulary Committee, British National Formulary. 55th ed. London: British Medical Association and Royal Pharmaceutical Society of Great Britain, 2008: 428-429
Can I take the pill so I don't have a period while I'm on holiday?
It's usually fine to run two packets back-to-back without the usual seven-day break. This will stop you having a bleed.
Explanation
If you take two packets of your contraceptive pill without a break in between, you are likely to have a period-free holiday. However, it's important to know what sort of contraceptive pill you are on. If you are taking a standard contraceptive pill that comes in a 21-pill packet with all the pills the same colour, it's fine to start taking the second packet straight after the first.
If you have a 28-day packet (once a day, every day), the last seven pills are dummies (inactive pills) to remind you when to start the next pack. You need to know which ones are the dummies and not take these if you are taking two packets back-to-back.
In some contraceptive pills, the dose of hormones is different for different weeks of the cycle (eg Trinordiol or Logynon ED). It's not reliable to take packets of these contraceptive pills back-to-back. Ask your GP, family practice nurse or pharmacist for advice.
After running two packets of the contraceptive pill back-to-back, you should take the usual seven-day break. It's best not to take more than two packets of the contraceptive pill back-to-back. If the lining of the womb (uterus) doesn't have a bleed for more than a couple of months, it carries on building up and you will probably get bleeding between your periods (breakthrough bleeding).
Sources
- Guillebaud J. Reducing withdrawal bleeds. Lancet 2000; 355(9221):2168-2169
- Regis D, Ruddock B. Timing oral contraceptives to delay menses. Can Pharm J 2003;136(8):39-40
Is it true that missing a combined pill at the start or end of the packet is more risky than missing one in the middle?
Yes, missing a contraceptive pill at the start or end of the packet increases the length of time that you're not protected and makes it more likely that your contraception won't work.
Explanation
The combined pill partly works by effectively shutting down your ovaries. In the pill-free period between packets, the usual balance of hormones starts to return and your ovaries begin to prepare to produce an egg. However, once you start the new packet, the ovaries shut down again and ovulation is prevented. If you miss a pill at the beginning or end of your cycle, your pill-free period is increased and the signals of the contraceptive pill that usually tell your ovaries not to produce will have worn off. Your ovaries will be working and it may be too late to prevent ovulation. You will need to start taking the next packet straight away and either not have sex or use additional barrier contraception, for example condoms, for seven days.
If you have missed two or more contraceptive pills from the first seven in the packet and had sex since finishing the previous packet, there is a high chance the contraceptive pill won't work. You may wish to use emergency hormonal contraception (the 'morning after pill'). You can get this from a pharmacy or family planning clinic, or your GP can write you a prescription. Always read the patient information leaflet that comes with your medicine and if you have any questions, ask your pharmacist for advice.
If you miss one combined pill in the middle of the packet, when the action of the ovaries is generally well blocked, there is less risk of pregnancy. As long as you don't miss more than one contraceptive pill, you don't need to use any extra contraception. Take the next pill as soon as possible and continue as usual.
It's important to be aware that if you miss a progestogen-only pill, you are much more likely to become pregnant than if you miss a combined contraceptive pill. Always read the patient information leaflet that comes with your medicine and if you have any questions, ask your GP, family planning nurse or pharmacist for advice.
Sources
- Joint Formulary Committee, British National Formulary. 55th ed. London: British Medical Association and Royal Pharmaceutical Society of Great Britain, 2008: 428-429
Related topics
This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Bupa doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.
Publication date: November 2008
Hormonal contraception factsheet
Visit the hormonal contraception health factsheet for more information.
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