Barrier Methods Of Contraception

Barrier methods of contraception are so-called because they prevent the sperm from meeting an ovum by placing a physical barrier in between. Barrier methods are some of the oldest forms of contraception; scientific and medical research has now removed much of the guesswork of old barrier methods, and made their modern equivalents very efficient at preventing conception.

The barrier between the sperm and the ovum is often a thin membrane of latex or rubber, worn by the man as a sheath over the penis, or by the woman as a cap over the cervix. A new barrier method — a variation of the oldest — consists of a small sponge placed high in the vagina. The barrier may also be formed by a layer of foam, cream or jelly, which also contains spermicidal chemicals to incapacitate or kill the sperm. The most effective barrier contraception combines two of these methods, for instance the sheath plus foam or a cap plus spermicidal cream.

To anyone who accepts the theory of contraception, there are no real ethical problems posed by barrier methods. They do not alter the body’s hormones, or necessitate sexual abstinence, or cause early abortions instead of preventing conception. None of the barrier methods has been given anything like the amount of medical research allocated to the pill and IUD, because they are generally classified as ‘non-medical’ methods. Therefore it is difficult to say with absolute certainty that barrier methods have no medical side-effects. However, caps and sheaths have been in use for so long, and have been used by so many millions of people throughout the world, that it is unlikely that this is so — any links would surely have become evident as a consistent pattern in barrier method users.

One study reported in 1981 did cause concern as it seemed to link the use of spermicide near conception with an increase in congenital malformations of the foetus. Theoretically, a sperm which has travelled through a layer of spermicide could have been damaged, thus altering its pattern of chromosomes. However, the Which? Guide to Birth Control described it as a study which ‘unfortunately … raised more questions than it answered’. For instance, the rate of malformation in spermicide users was 2.2%, while it was 1.1% in the control group — but the national rate of congenital malformation is 2.1%. Also, those studied were couples who had had a prescription for spermicide in the previous two years; there was no definite proof that the spermicide had been used at or near the time of conception. The general consensus among contraceptive experts is that the matter should continue to be studied, but that there is at the moment no cause to believe that spermicide can damage the developing foetus.

The problems relating to barrier methods are not so much ethical as practical, mechanical and aesthetic. Some couples dislike the thought of using any mechanical device to prevent conception. If a sheath, or spermicide alone, is used, then contraceptive precautions have to be taken actually at the time of lovemaking. Some women are unhappy about touching their genitals, and so may find inserting a cap distasteful. All the barrier methods require some kind of preparation for sex; some can be rather messy! A couple thinking of using a barrier method consistently should look very carefully at the requirements and mechanics of the chosen method, and decide whether they are acceptable, and whether they are willing to establish or alter their patterns of lovemaking accordingly.

All barrier methods are useful for couples who don’t want to use the pill or IUD, or for those for whom the pill is unsuitable, e.g. older women, those with a history of heart or cir culatory disease. As with many methods of contraception, the success of barrier methods depends very much on the motivation of both partners involved. It is easy to be irresponsible, forgetful or erratic over using barrier methods, which can result in a high failure rate; on the other hand, when used conscientiously barrier methods can have a very low failure rate. Also, there is no problem with re-establishing fertility when a couple wants to conceive a baby after using a barrier method; both husband and wife remain fertile throughout the time of using the contraception.

More Information on Barrier Methods

Mechanical methods of contraception aim to place a barrier between sperm and egg, and so prevent them meeting. The condom or sheath or French letter, is the most popular method of contraception for young persons who are at the beginning of their sexual experience. The sheath (condom) is basically a tube-shaped piece of thin latex rubber, closed at one end, which is shaped to fit closely over the man’s penis. When the man ejaculates at orgasm, sperm are trapped in the closed end of the sheath. The sheath should be unrolled gently over the penis after it has become erect but before intercourse starts. Most sheaths have a teat or reservoir end which will safely hold the ejaculated sperm. This should be pinched flat as the sheath is put on, to make sure an air bubble is not created which could either cause the sheath to burst or force semen down the sides of it and out into the vagina.

After climax, the sheath should be held at the base, while the man withdraws his penis to prevent the sheath slipping off inside his partner. For maximum safety he should withdraw before the penis has relaxed. Genital contact should be avoided afterwards and a new sheath used if the couple make love again. Some men complain that sheaths reduce sensation, although it is more than likely that emotional, rather than actual, difficulties are the basis for such complaints. New materials have recently been produced that despite offering maximum sensitivity, by means of thinner walls, still retain great strength. With careful use, the sheath can be as much as 95 per cent effective and it has the added advantage of providing

some protection against sexually transmitted diseases. Slightly better results are obtained with barrier methods used by women: the diaphragm and Dutch cap. Diaphragms are circular domes made of thin rubber with a flexible spring rim. They are designed to fit snugly over the cervix, lodging securely between the pelvic bone and the vaginal vault, and held in place by the muscles around the vagina. The correct size should be chosen by a trained doctor or nurse. A diaphragm can be slipped into place some time before intercourse occurs. To do so, the woman squeezes the rim and guides the device up into her vagina. It then opens out and covers the cervix. Even the best-fitted diaphragm cannot be guaranteed to exclude all sperm and for extra safety, women are advised to use a spermicide as well. To allow the spermicide to act fully, the diaphragm should be left in place for at least six hours after the last act of love-making. To remove it, the woman hooks her index finger over its rim and pulls out the device.

In some cases, the diaphragm is an unsuitable method. A woman with a retroverted womb* will find that the device does not lodge securely, and some women find that their vaginal muscles are too weak to hold a diaphragm in place. In such cases, a cap or cervical pessary can be ideal. This is a cone of rubber shaped like a thimble which fits exactly and tightly over the cervix. It, too, may be made even safer by the use of spermicides, although some doctors believe that the suction effect of the cap over the cervix is enough to produce a secure barrier. To remove a cap, the woman must first ‘flick’ the cap back off the cervix to break the seal and then hook it out. There are plastic applicators available to help with this procedure, if necessary.

A third form of female barrier is the contraceptive sponge. It is made of polyurethane foam, measures 5cm across and has a dimple in one site to fit over the cervix. The foam is impregnated with spermicide, and one size fits all women. The sponge must be moistened before use, to activate the spermicide. It can be inserted up to 24 hours before intercourse and will protect against as many acts of intercourse as the

couple wish to have. The sponge is withdrawn with the aid of a small loop sewn into one side and thrown away. Like the sheath, it is available from chemists without prescription. Studies suggest that its safety rate is not very high, about 85 per cent.