Barrier contraception is the only form that can both prevent pregnancy as well as sexually transmitted infections. These prevent pregnancy by physically preventing sperm from meeting an egg. You can get free condoms from contraception clinics, sexual health clinics and some GP surgeries.


Male and female condoms are available. They work by stopping the sperm meeting an egg. Male condoms are more common of these two types. They are made from thin latex (a type of rubber) or polyurethane (a type of plastic) and fit over a man’s erect penis. Female condoms are made from polyurethane and are put in the vagina to loosely line it. Condoms are the only contraception that gives any protection against sexually transmitted infections.

How effective are they?

The efficacy of both types of condoms are highly dependent on the individuals using them, in terms of motivation as well as user skill. Male condoms are more effective than female condoms. If used perfectly, male condoms are 98% effective; which means that 2 women out of a 100 who rely on condoms will get pregnant in a year. If used perfectly, female condoms are 95% effective; which means that 5 women out of a 100 who use female condoms will get pregnant in a year.

However, when looking at studies on the typical use of condoms, the efficacy rates really drop. With typical use of male condoms around 18 in 100 women whose partners use a condom will get pregnant in a year. With typical use of female condoms around 21 women out of a 100 will get pregnant in a year

Pros and cons

Condoms are the only form of contraception which gives protection against most sexually transmitted infections. Because of this quality, it is often used as a second contraceptive agent. It also has the benefit of being a non-hormonal contraceptive.

The main drawback with condoms is the high failure rate. There are lots of reasons for this such as condoms splitting or slipping off, not being put on early enough or taken off too soon. One other problem with male condoms is that both male and female partners can develop a sensitivity to the latex. If this happens, switching to polyurethane condoms will resolve the situation.

Relevance in PH

Condoms are really important in protecting against sexually transmitted infections and can also be useful as a second form of contraception to give added protection against pregnancy. For those with PH, it would be strongly recommended not to rely on this method alone due to its high failure rates.

Q. What do I do if the condom splits?

If you are using condoms as your only form of contraception, a split condom puts you at risk of pregnancy. This would be a time to organise emergency contraception. If you are using a second form of contraception as well, which we would strongly recommend, you will not be at risk of pregnancy but could still be at risk of sexually transmitted infections. If you think this is the case, seek advice from your local sexual health clinic or GP surgery.

Diaphragms & caps

Diaphragms and caps are small domes made out of silicone or latex that fit inside the vagina to form a barrier between the sperm and the egg. Diaphragms are slightly larger than caps. To be effective they both need to be used with spermicide. Diaphragms and caps are inserted before sex and have to be left in position for at least 6 hours afterwards. New spermicide needs to be applied if sex takes place more than 3 hours after putting it in.

How effective are they?

If used perfectly, diaphragms and caps are between 92-96% effective; this means between 4 and 8 women out of a100 who use this method will get pregnant in a year. However, this method is again, very dependent on its user and typical use gives a much lower efficacy rate. With typical use around 24 out of 100 women using diaphragms and caps will get pregnant in a year.

Pros and cons

The benefit of this contraception is that it is not hormonal and rarely gives any unwanted effects.

The main drawback of this method is the very high failure rates. It is also a method which requires a woman to feel very comfortable inserting and removing the device from her vagina. Women can also develop sensitivities to the latex or to the spermicide.

Relevance in PH

This form of contraception is not recommended for those with PH. The risk of pregnancy is too high.

The contraceptive patch and vaginal ring

These are two other forms of hormonal contraception; neither of these types of contraceptives are used commonly in the UK.

The contraceptive patch is a beige coloured patch approximately 5cm x 5cm in size. It sticks onto your skin and one patch lasts a week. You change the patch every 7 days for 3 weeks then have 1 week without a patch. It can be put on most areas of your body as long as the skin is clean, dry and not very hairy.

The contraceptive vaginal ring is a soft, flexible plastic ring approximately 5cm in diameter. It is placed in the vagina but does not need to be in an exact position. The ring should be left in place for 3 weeks and then removed. Another ring is inserted a week later after a 7-day break.

They both release the same two types of hormone found in the combined oral contraceptive pills (COCP). They 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.

How effective are they?

Contraceptive patches and vaginal rings are as effective as COCPs. With perfect use, they are more than 99% effective; this means that less than 1 women in 100 using these forms of contraception will get pregnant in a year. With typical use however, they become less effective with around 9 women in 100 using the patch or vaginal ring getting pregnant in one year.

Pros and cons

The pros and cons for the patches and vaginal rings are very similar to the COCP.

One benefit of these particular forms of contraception is that the hormones are absorbed through the skin or vaginal wall, not the stomach, so they are not affected by vomiting and diarrhoea.

They can cause positive changes to a woman’s periods and premenstrual symptoms but can also cause unwanted side effects such as headaches, nausea, breast tenderness and mood changes but these will often settle down after 3 to 6 months of using a new form of hormonal contraception.

Because the patch and vaginal ring release a type of oestrogen, they still have the more serious side effects linked to this hormone; that is they give an increased risk of a blood clot in a vein (leading to venous thrombosis) or in an artery (leading to arterial thrombosis or heart attack or stroke). If you have significant risk factors for blood clots or heart disease and strokes, you should not use the patch or the vaginal ring.

Relevance in PH

These forms of contraception are not recommended in women with PH due to the risk 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. I haven’t heard of the contraceptive patch before. Is it new?

The contraceptive patch was first available in 2003. It is not used very much. It is not recommended for women with PH due to the oestrogen-type hormone released by them. This increases your risk of blood clots which can be very harmful in PH.

Natural planning method

The natural family planning method relies on knowledge of the menstrual cycle and being able to recognise the different phases within your own monthly cycle. It then requires either abstinence from sex or use of condoms during the fertile time of your cycle.

How effective is it?

Typical use of natural planning will lead to around 24 out of 100 women using this method getting pregnant in a year.

Pros and cons

The benefit of this method is that it is natural-with no use of hormones or devices. But this is its biggest drawback too, as it relies heavily on very disciplined and careful use which is often not attainable in real life and leads to a very high failure rate.

Relevance in PH

This method of contraception is not recommended for women with PH. Although there are no hormones to interact with medication or give side effects, the risk of pregnancy is too high.

Q. I’ve heard natural planning methods can be really effective. Why is this such a risky form of contraception to use?

Using a natural planning method requires a regular cycle so the woman can be sure when she is going to ovulate and also needs great discipline and restraint so that during the fertile time, sex is avoided. In theory, this could be quite effective which is why you will find figures quoted on this method as 99% effective. This is what is referred to as perfect use. We all know though, that life is not perfect and occasionally a woman’s cycle may change in length one month, or the woman, for many reasons, may not avoid sex at the right time. All these variables reduce the effectiveness of the natural planning method. With typical use, ie taking into account what life is really like, it is only 76% effective; that means nearly a quarter of those using this method, will get pregnant in one year.