Before learning about the various modes of contraception, it would be wise to review some basic science material on the anatomy and physiology of reproduction.
- Historical methods: periodic abstinence
Following ovulation, the ovum can be fertilized within an 24 hour timespan. Sperm has been shown to be capable of 3-5 day survival in utero, in some instances even up to 7 days. The theoretical fertile timeframe thus stretches from 5 days before ovulation until the day after. Statistically, ovulation occurs most commonly at day 14 of the menstrual cycle, but there is considerable variety in the day of ovulation from cycle to cycle. At ovulation, the formation of a corpus luteum causes an increase in progesterone production. Among its many physiological effects, progesterone causes an approx. 0,5 centigrade increase in basal body temperature following ovulation. Also, LH gives an increase in oestrogen production, causing softening and upward rising of the uterus. These changes in basal body temperature and uterine consistency have been utilized as an indicator in family planning to foresee when a woman is fertile.
Oral contraceptives are also known as birth-control pills. These are used to prevent pregnancy and it is important to realize that they do not protect against STDs or HIV. Birth-control pills release the two female sex hormones, estrogen and progestin. The combination of the two hormones work by prevention ovulation, in other words the release of eggs from the ovaries. Without releasing an egg, the women can not get pregnant. The hormones also effect the lining of the uterus from developing to prevent pregnancy and change the mucus at the cervix which is the opening of the uterus so that sperm cannot enter. Birth-control can have other effects like treating acne and relieving the symptoms that occur before the menstrual period each month, depending on the brand of birth-control. Birth-control pills have been found to be 99% effective when used correctly, meaning taken at the same time every day.
Copper Intrauterine Device (IUD)
Hormonal Intrauterine Device (IUD)
Intrauterine Devices (IUD) have been used for prevention of pregnancy for the past 30 years. The exact mechanism is not fully understood. A number of mechanism are proposed, there is an effect on sperm motility & survival and there is a change in the endometruim that is unfavorable for implantation.More that one mechanism is likely. The first generation IUDs were unpopular because on increased menstrual loss(Menorrhagia) and increased pain around period time(dysmenorria). There was also an increase in pelvic infection. For these reasons IUDs lost popularity as method on contraception. The newer generation of IUDs(Mirena) are coated in a progesterone and this helps to reduce menstral loss and pain. This circumvents the two most common drawbacks on unmedicated IUDs. Some irregularity of menstrual cycle may occur during the first 3-5 months.
The diaphragm was first introduced in 1882. Modern diaphragms are dome-shaped latex rubber devices covering the cervix, thus acting as a mechanical barrier to sperm, preventing their entry into the uterus. It is generally recommended that the use of a diaphragm is supplemented with a spermicide, and used correctly this combination has an efficacy of 92-96%. It is yet unknown whether the use of diaphragms without spermicides is comparably effective.
Several sizes and types of diaphragms exist, differing in the design of the rim of the device. The selection of diaphragm is made during vaginal examination, where the cervix is assessed and the appropriate size of the diaphragm determined. Practically, this is done by measuring the distance from the posterior fornix to the symphysis, and finding a diaphragm of comparable diameter. A correctly fitted diaphragm should cover the cervix and sit tightly against the posterior part of the symphysis. The device should not be felt by the client while in situ. Fitting of the diaphragm must be taught gradually, focusing first on locating the cervix, then on fitting and removing the device, and finally on applying the spermicidal. About half an hour should be reserved for this purpose. Spermicidal gel is applied on both sides of the diaphragm, and if intercourse does not take place within 3 hours, additional gel should be added. Following intercourse, the diaphragm should be left in for about 6 hours, but not more than a total of 24 hours to avoid the development of toxic shock syndrome. Proper hygiene is crucial; the diaphragm must be washed thoroughly with mild soap and water.
Significant changes in body weight might necessitate a change in the size of the diaphragm. Also, a routine control every 6 month is recommended to ensure proper fitting. The diaphragm should be replaced annually. Diaphragms may increase the risk of urinary tract infections and provides no protection against STDs. Toxic shock syndrome is a feared complication if a diaphragm is carried for more than 30 hours.
Cervical caps are rubber devices that act as mechanical barriers for sperm, capping the cervix, being held in place by suction. Cervical caps are not as commonly used as diaphragm, apparently mainly because of greater difficulties with fitting. With correct use, an efficacy of 92-96% is obtained used with the addition of a spermicide.
The cap is introduced while squeezing it between the three first fingers. Thumb pressure is then released, and proper placement over the cervix is verified. Removal is accomplished by inserting a finger under the rim, thus removing the suction.
Usage guidelines and complications of use are identical to those mentioned in the section on diaphragms.
Sponges are made from polyurethane covered in a spermicide. They are inserted into the vagina 15 minutes prior to intercourse, and must be left in situ for 6 hours after intercourse has occurred. Protection can be left in situ for up to 12 hours, and several intercourses can take place without the need of changing the sponge.
Efficacy of condoms are reported differently ranging from 98 to 95% when used properly and consistently. Condoms are a barrier method worn by the male on his penis to stop the ejaculation fluid from entering the female. The obvious benefit from the use of condoms is protection against STDs, including HIV, and the absence of systemic effects. Condoms are inexpensive and easy to get, they do not require a prescription, and can be used with other birth control methods. The increase in condom use can limit the number of unwanted pregnancies and STDs.