Contraceptive pills

Combined Oral Contraceptive Pill (COCP)

What it is and how it works

When people talk about ‘the pill’, it is most likely to belong to this group. These tablets contain two types of hormone- one from a group of synthetic hormones similar to progestogen and one from a group of synthetic hormones similar to oestrogen. When taken regularly, the COCPs switch off the ovaries and stop ovulation. They also thicken the cervical mucus to stop the sperm reaching the egg and make the lining of the womb thinner, so a fertilised egg cannot implant.

Most COCPs are taken every day for 21 days (starting on the first day of your period) followed by a ‘pill free week’ after which a new pack is started. There are packs of ‘EveryDay’ pills which contain 28 tablets, 21 of which are active and 7 of which are inactive. These can be useful if you find it hard to remember when to restart your pill pack after the pill free week. The pills do not have to be taken at the same time each day, but it’s advisable to take them at a particular point of your daily routine (eg brushing your teeth in the morning) so that they are less likely to be forgotten.

How effective is it?

When taken according to instructions, the pill is over 99% effective; which means that less than one woman in 100 who take the pill will get pregnant in a year. However, because it can be easy to forget to take a tablet every day, because absorption can be affected by vomiting or diarrhoea or by other drugs, such as antibiotics, the reality is that the pill is not quite so efficient. When looking at ‘typical use’, approximately 9 women in 100 who take the pill will get pregnant in a year.

Pros and cons

The benefit of the COCPs are that the contraception comes in a tablet form, which a lot of women prefer to injections, implants or devices. The combination of the hormones can also be beneficial for problems related to the menstrual cycle. Women on the COCP can find their periods to be lighter, more regular and less painful, have less problems with premenstrual symptoms and have less severe acne.

However, the combination of hormones can cause more troublesome symptoms such as headaches, nausea, breast tenderness, mood changes or irregular bleeding. If you do experience these, they may settle down after 3 to 6 months of taking the pill. If they don’t, it may help changing the brand of pill to see if you can find one that suits you better.

The COCP does also have more serious side effects due to the oestrogen-type hormone present in them. Although they are serious risks, they are not very common. All types of oestrogen increase the risk of women having a blood clot in a vein (leading to venous thrombosis) or in an artery (leading to arterial thrombosis or heart attack or stroke). For this reason, using the COCP is not an option for everyone.

It is contra-indicated in women who have had a blood clot of any kind in the past; who have a close family member who has had a blood clot under the age of 45; who have severe migraines especially if they have warning symptoms (or aura); who have heart disease or severe hypertension; who have breast cancer or who have liver disease. It is also advisable to be cautious of using the COCP if you have one of the following risk factors for blood clots: being aged over 35, being a smoker, being very overweight, having mild to moderate migraines, having high blood pressure, having Diabetes or being immobile for a long time. If you have two or more of these risk factors it is not advisable to use the COCP.

The COCP also has been linked to a slightly higher chance of breast cancer and cervical cancer. The risk reduces over time after stopping the pill.

Relevance in PH

The COCP is not generally recommended for women with PH because of the concerns over the possibility of blood clots. For most forms of PH, the risk of blood clots is not necessarily any greater than in a woman without PH, but the consequences can be far more damaging.

Q. What do I do if I miss a pill?

A ‘missed pill’ can put you at risk of pregnancy depending on where you are in the pack. You have ‘missed a pill’ if you take it more than 24 hours after the normal time. Each pack has clear instructions what to do if you have missed a pill. The instructions will vary depending on whether you are close to the pill free week or not. Remember that vomiting and diarrhoea can lead to the same effect as missing a pill. If in any doubt, use a second form of contraception such as a condom for 7 days.

Q. I had been taking the COCP for several years with no problems when I was diagnosed with PH. I was told immediately I had to come off it. Is this correct?

Women with PH are normally advised to switch to an alternative if they are using the COCP. This is because of the increased risk of blood clots with the COCP and the damaging long term effects of having a blood clot on the lungs.

Progesterone Only Pill (POP)

What it is and how it works

This is commonly referred to as the mini-pill and contains a synthetic hormone similar to progestogen. There are lots of different types of mini-pill all with slightly different progestogen-type hormones. The POP works by thickening the cervical mucus to stop the sperm reaching the egg and by thinning the lining of the womb to prevent a fertilised egg implanting. If the POP contains a particular type of progestogen (Desogestrel), its main way of working is by stopping ovulation as well as affecting the cervical mucous and the lining of the womb. Because of how it works, the POP has to be taken every day without a break with and around the same time each day. If they are not taken in this way, they are not as effective. Desogestrel-containing POPs can have more leeway in the time of day you take them because they act by stopping ovulation. It is still a good idea though, to take them at the same point in your daily routine to help you remember to take it every day.

How effective is it?

When taken according to instructions, the pill is over 99% effective; which means that less than one woman in 100 who take the pill will get pregnant in a year. However, because there is such a small window of time to remember the POP each day, and because absorption can be affected by vomiting or diarrhoea, the reality is that the POP is not quite so efficient. When looking at ‘typical use’, approximately 9 women in 100 who take the pill will get pregnant in a year.

Pros and cons

The benefit of the POP is that the contraception comes in tablet form which can be more acceptable to women than injections, implants or devices. With Desogestrelcontaining POPs, bleeding may become lighter and less frequent.
POPs which do not contain desogestrel can cause more problematic changes in your periods. Bleeding may be heavier or lighter, more or less frequent, last longer or stop altogether. Other side effects include headaches, acne, breast tenderness and mood changes but these tend to settle within a few months of starting a POP.

Relevance in PH

For women with PH, the POP has the advantage over the COCP because it does not contain oestrogen-type hormones. This means there is no increased risk of blood clots. However, there is a big issue with its reliability, especially the POP’s that have to be taken within three hours of the normal time. For this reason, if a POP seems the best option for you to choose, one containing desogestrel (such as Cerazette) would be the recommended option.

Q. Does the mini-pill interact with my PH drugs?

The only PH drug which has the potential to interact with the mini-pill is Bosentan, an Endothelin Receptor Agonist. It is thought Bosentan makes the mini-pill less effective, so if you are on this drug as part of your PH medication, you can take an altered dose of the mini-pill or you will need to consider a second form of contraception as well. For example, someone on Cerazette and Bosentan would be advised to take two Cerazette tablets a day, instead of one.

Q. What do I do if I miss a pill?

A ‘missed pill’ puts you at risk of pregnancy wherever you are in the pack. You have ‘missed a pill’ if you are more than 3 hours late taking the POP (or more than 12 hours late taking the desogestrel POP). Each pack has clear instructions what to do if you have missed a pill. Remember that vomiting and diarrhoea can lead to the same effect as missing a pill. If in any doubt, use a second form of contraception such as a condom for 7 days.

Q. I’ve heard the mini-pill is not very good at controlling your periods and you can get lots of irregular bleeding. Does this happen?

The effect of the mini-pill on periods can vary hugely from person to person. Some women will have significant problems with irregular bleeding on the older types of mini-pill. Because the desogestrel POP works by stopping ovulation, this type of minipill often gives really good cycle control and far fewer problems with unwanted bleeding.

IMPORTANT INFORMATION ABOUT NAUSEA AND VOMITING: