The cervical mucus methodattempts to
pinpoint the fertile period by observing
and charting the amount and appearance
of cervical mucus during the menstrual
cycle. Recognized changes in the mucus
occur before and often at ovulation. The
symptothermal methodcombines the
temperature and cervical mucus methods.
contraception, withdrawal method
ofSee coitus interruptus.
contraceptiveAny agent that reduces
the likelihood of conception. (See also
contraception.)
contraceptive implantA hormonal
method of contraceptionin which long-
acting contraceptive drugs are inserted
under the skin. An implant consists of a
small rod that steadily releases a pro-
gestogen druginto the bloodstream.
contraceptives, injectableA hormonal
method of contraceptionin which long-
acting progestogen drugsare given by
injection every 2–3 months. Injectable
contraceptives are very effective but may
cause menstrual disturbances, weight
gain, headaches, and nausea, especially
during the first few months of use.
contractions, uterineSpasms of rhyth-
mic, squeezing muscular activity affecting
the walls of the uterusduring childbirth.
Regular contractions indicate the start
of labourand increase in strength and
frequency throughout the first stage.
(See also Braxton Hicks’ contractions.)
contracture A deformity caused by
shrinkage of tissue in the skin, muscles,
or tendons that may restrict movement
of joints. Skin contractures commonly
occur as a result of scarring following
extensive burns. Other types are caused
by inflammation and shrinkage of con-
nective tissues. Examples are Dupuytren’s
contractureand Volkmann’s contracture.
contraindicationFactors in a patient’s
condition that would make it unwise to
pursue a certain line of treatment.
contrast mediumA substance opaque
to X-rays, introduced into hollow or
fluid-filled body parts to show them up
on X-ray film. Barium is one of the most
commonly used contrast media (see
barium X-ray examinations).
controlled drugOne of a number of
drugs subject to restricted use because
of their potential for abuse. They includeSome spermicides should not be used
with rubber barrier devices.
Mechanical and chemical means used
together correctly can be highly effec-
tive in preventing conception.
contraception, emergencyMeasures
to avoid pregnancyfollowing unprotec-
ted sexual intercourse. There are 2 main
methods: hormonal and physical. In the
first, oral contraceptives (the “morning
after” pill) are taken in a high dose as
soon as possible, but not longer than
72 hours, after unprotected intercourse,
with a second dose taken 12 hours later.
They may be given as a high-dose pro-
gesterone-only pill or as a high-dose
combined (oestrogenand progesterone)
pill. In the physical method, an IUDis
inserted by a doctor within 5 days of
unprotected intercourse.
contraception, hormonal methods
of The use by women of synthetic pro-
gestogen drugs, which are often combined
with synthetic oestrogens, to prevent
pregnancy. These drugs suppress ovula-
tionand make cervical mucus thick and
impenetrable to sperm. They also cause
thinning of the endometrium(lining of the
uterus), which reduces the chance of a
fertilized egg implanting successfully. The
best-known form of hormonal contracep-
tion is the contraceptive pill (see oral
contraceptives). The hormones can also
be given as contraceptive implantsunder
the skin, by injection (see contracep-
tives, injectable), or be released by IUDs.
contraception, natural methods of
Methods of avoiding conception based
on attempts to pinpoint a woman’s fer-
tile period around the time of ovulation,
so that sexual intercoursecan be avoided
at this time. The calendar methodis based
on the assumption that ovulation occurs
around 14 days before menstruation. Be-
cause of its high failure rate, it has been
largely superseded by other methods.
The temperature methodis based on the
normal rise of a woman’s body tempera-
ture in the second half of the menstrual
cycle, after ovulation has occurred. The
woman takes her temperature daily
using an ovulation thermometer. Sex is
considered to be only safe after there
has been a sustained temperature rise
for at least 3 days.CONTRACEPTION, EMERGENCY CONTROLLED DRUGC