How the most popular birth control methods work and can they cause abortion?
It seems like the definition of pregnancy should be simple: You either are or you're not. But medical experts disagree with some conservative lawmakers about what constitutes a pregnancy and therefore whether some forms of birth control cause an abortion.
However medical experts who study reproduction say many such arguments are based on a lack of understanding of the human reproductive process. They argue that birth control methods do not cause abortions. In most methods of contraception, egg and sperm never meet, medical experts say, so there is no fertilization – and therefore there cannot be a pregnancy.
With this discussion in mind, Paste BN set out to explain the biology:
What is pregnancy and how is it defined?
In nature, about half all fertilized eggs are lost before a woman misses a period, according to the University of California, San Francisco.
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Birth control methods, from least to most effective
In an attempt to clear up the confusion, below is a list of some of the most popular birth control methods, how they work and how effective each option is:
Fertility awareness
Effectiveness: 77% to 98%
Avoid sex when eggs could be present, about eight days per cycle.
Condoms
Effectiveness: 87%
Prevents sperm from entering the vagina.
Birth control pills
Effectiveness: 93%
A pill taken daily that stops the release of eggs from the ovaries.
Birth Control Shot
Effectiveness: Over 96%
A shot given once every three months that stops ovulation.
Emergency Contraception
Effectiveness: Over 97% - 99% (Most effective within 24 hours, can be taken up to 5 days after having sex.)
Sometimes called “the morning after pill,” emergency contraception delays or prevents the release of an egg from the ovaries. It does not end a pregnancy that has already started. Emergency contraception must be taken within five days of unprotected sex.
IUD
Effectiveness: 99.2% to 99.8%
An intrauterine device is a piece of thin, flexible plastic about an inch long inserted into the uterus. Some contain copper, some contain small amounts of hormones. They last three to 10 years.
The copper IUDs change the way sperm move so they can't get to the egg. The hormonal IUDs thicken cervical mucus so sperm cannot enter the uterus and can inhibit ovulation.
Birth control implant
Effectiveness: 99.9%
A flexible plastic rod the size of a matchstick placed under the skin of the upper arm, which releases a low, steady dose of the hormone progestin. The hormone prevents ovulation and thickens the cervical mucus to block sperm from entering. Lasts for about five years.
Sterilization
Effectiveness: Over 99%
In women, the fallopian tubes are blocked or removed so no eggs can enter the uterus.
In men, the tubes that carry sperm (vas deferens) are blocked so no sperm are released.