Family planning, also birth control: several known methods, my personal experience.
I'm not a doctor, just a married woman who has three perfectly planned children and tends to read small print. I used several methods of family planning in past eleven years. Here is an overview of family planning methods with personal comments.
Pills and patches: contraceptive pills contain progesterone and/or estrogen, both are synthetic steroids resembling natural hormones in structure and function. They don't protect from STD and have to be taken every day in approximately same time. They are 99% effective with ideal use and 95% effective typically. Pills are reversible, but not immediately. It takes several periods to reestablish fertility once pills are discontinued. I got pregnant three month after I stopped taking pills. Pills often have additional to family planning effects, like lessening menstrual cramps, making a cycle regular, and even treating acne. They also can have less desirable effects: increased blood coagulation, weight changes and diminished libido. Pills can alter woman's mood -- sometimes treating mild depression, sometimes causing it. Pills are not recommended family planning method for women with history of a migraine or risk of a stroke. Certain antibiotics interfere with contraceptive pills. Since the Pill is prescription only, you will get to discuss everything with your physician before deciding which type of contraceptive pills suits you better. Patches release same hormones in smaller doses round the clock through skin. I never tried that.
Barrier methods: condoms and diaphragms. 95%-99% effective, depending on manner of use. These methods are immediately reversible, don't alter biochemistry of your body and protect from STD as well as from pregnancy. Barrier methods of family planning have no medical disadvantages. However, there are practical or psychological drawbacks: use of condoms and diaphragms require some interruption. Some women are too shy to insist on using condoms. And, as well as with pills, you should remember to have it with you. I don't think condoms are practical family planning method for a monogamous relationship. Also known as family.
Creams and gels, local tablets: spermicide agents in various forms women put in their vagina some time before the intercourse. These methods of family planning have all disadvantages of condoms and diaphragms, but not as effective. I don't know any real data, just anecdotal evidence from girls from my college who got pregnant despite using spermicide creams or tablets. Creams are rather messy and hard to apply correctly. Tablets can cause irritation and burning sensation. Unlike pills they don't interfere with body chemistry.
IUD: stands for Intra Uterine Device. It is a thin copper wire coil bend into T-shape, about an inch long, with tails to pull it out. Once it is fitted into the cervix, it an stay there up to ten years. Any foreign object in cervix prevents conception. Additionally, copper is toxic for spermatozoids. Sometimes, IUDs are made to release hormones. IUD is not recommended for women with untreated vaginal infections, because of the increased risk of pelvic infection associated with IUD. The risk is even higher if infection is already present nearby. It is not recommended for women who never been pregnant. It is a most convenient family planning method I tried yet: once in place, you don't have to think about it any more. Unlike pills, it doesn't effect your weight or libido. Unlike condoms, it doesn't effect sensation for you or your partner. Unlike surgical methods, it is reversible. Obviously, it doesn't protect from STD. Some women experience worse menstrual cramps with IUD, but I don't.
Morning-after pill (Emergency Contraceptive Pill, ECP): it is not a family planning method, more like a quick fix on unplanned. I had that once ten years ago and didn't like it at all: I felt for a day as during my worst period, plus nausea. Morning-after pill is a month worth of hormones in one dose. Back were I'm from doctors warned from using these pills more than once a period, but I don't know if this advice was founded. Sounds reasonable, anyway. ECP prevents ovulation, or fertilization, or implantation of blastocyst, depending on stage in period and time after intercourse, which should not exceed three days.
There are several other family planning approaches I'm not personally familiar with. Rhythm method is based on attempts to guess the moment of ovulation and to avoid sex when conception is most probable. It is claimed to be 80% effective. Sterilization for men and women is certainly affective, but looks too final to me.
See also: early pregnancy, due date, children.