Page 101 - 86 human physiology part-2

Chapter 16

specifically be referred to as contraception. Contraception differs from abortion in that the former
prevents fertilization, while the latter terminates an already established pregnancy. Methods of birth
control which may prevent the implantation of an embryo if fertilization occurs are medically
considered to be contraception. It is advised to talk with a doctor before choosing a contraceptive. If
you have genetics problems or blood conditions, such as factor V leiden, certain contraceptives can be
deadly.

Type Procedure Method Effectiveness Risks
Refrain from sexual
Abstinence No sperm in vagina 100% None
intercourse
Intercourse is avoided for
about an 8-day span every fertilization is only
month in middle of her possible during 8-
Rhythm Method 70-80% None
cycle, from about five days day span in middle
before ovulation to three of menstrual cycle
days after ovulation.
The man withdraws his sperm are unable to
penis from the vagina at just enter vagina if male
Withdrawal 70-80% None
the right moment before penis is removed at
ejaculation. the right time
Tubal Ligation Oviducts are cut and tied No eggs in oviduct Almost 99% About 75%
(Vasectomy) Irreversible
Releases small
Hormonal IUD Flexible, plastic coil inserted amounts of estrogen. May cause
infections,
(intrauterine by physician In most cases, stops About 99% uterine
device) egg from developing perforation
and being released
Blood clots,
Oral Hormone medication taken Stops release of FSH More than 90% especially in
Contraceptive daily and LH
smokers
Contraceptive Tubes of progesterone Stops release of FSH
Implants implanted under the skin and LH More than 90% None known
Contraceptive Injections of hormones Stops release of FSH About 99% Possible
Injections and LH osteoporosis
Latex cup inserted into With Latex or
Diaphragm vagina to cover cervix Blocks entrance of spermicide, spermicide
sperm into uterus
before intercourse about 90% allergy
UTI, latex or
Latex cup held by suction Delivers spermicide
Cervical Cap Almost 85% spermicide
over cervix near cervix
allergy
Blocks entrance of
Polyurethane liner fitted
Female Condom sperm into uterus Almost 85% None
inside vagina
and prevents STD’s
soft sheath, made of latex or Blocks entrance of
animal membrane, encloses
Male Condom sperm into vagina 90% None
penis, trapping ejaculated and prevents STD's
sperm

316 | Human Physiology