The condome is the only contraception method that also protects against sexually transmitted diseases.
The contraceptive effect of barrier and natural methods in typical use is poor. They are only suitable for occasional use by persons for whom becoming accidentally pregnant does not pose a problem.
Users should be informed on postcoital contraception methods.
Barrier methods
The condom is the only method of contraception that offers protection from infection. That is why it should always be used in casual and new relationships, even if another method of contraception is used. The need and usefulness of condom cannot be overemphasized. Condoms without latex are also available Non-Latex Versus Latex Male Condoms for Contraception.
Oil-based lubricants and vaginal medications may rapidly damage the condom.
Various methods are available (not necessarily in the pharmacies but at least through the internet):
A contraceptive diaphragm is a thin dome made of latex. It is inserted into the vagina against the cervix. It should always be used with spermicide Diaphragm Versus Diaphragm with Spermicides for Contraception. Finding the right size of diaphragm usually needs help from a health professional.
A single size silicone diaphragm is also available.
A sponge is made of foam and impregnated with spermicide. It may be described as a "disposable one size diaphragm".
The diaphragm is associated with an increased risk for urinary tract infections and the sponge may predispose to the toxic shock syndrome.
Barrier methods are suitable for infrequent or casual contraception.
The effectiveness is significantly reduced by problems in the proper use.
Persons using barrier methods should be advised about the possibility of postcoital contraception.
Natural methods of contraception
Natural methods are based on abstention from sexual intercourse during the fertile period or on the use of barrier methods only during the times when becoming pregnant is probable.
Natural methods are unreliable. They may, however, be used if an absolutely reliable contraception is not required, e.g., when the woman wishes to somewhat lengthen the interval between two pregnancies.
The egg may be fertilized during less than 20 hours after ovulation. The sperm keep their fertilizing capacity often for three days, or even for six to seven days after the ejaculation. The fertile period is about ten days.
Devices that aim at predicting the time of ovulation are marketed on the Internet. The prediciton is based on the determination of luteinizing hormone in the morning urine using a dip stick.
In the rhythm method, the first eight days and (probably) the last ten days of a regular 28 day cycle are "safe".
In the basal temperature method, the time of ovulation is determined by measuring the basal body temperature. Intercourses are not allowed until when the temperature has been on a higher level for 3-4 days. The symptothermal method combines the temperature measurement with other symptoms of ovulation.
In the Billings method the woman observes the mucous discharge of the cervix.
The reliability of the natural methods varies very widely (Pearl index 1-40) depending on the user.
Regular exclusive breastfeeding acts as an effective contraceptive method until the first menstruation, yet for no longer than six months after childbirth Lactational Amenorrhea for Family Planning.