A woman’s ability to conceive depends
on normal ovulation(the monthly pro-
duction of a healthy ovum by 1 of the
ovaries) and the ovum’s unimpeded
passage down a fallopian tube towards
the uterus; on thinning of the mucus
surrounding the mouth of the cervix
to enable sperm to penetrate; and on
changes in the lining of the uterus
which prepare it for the implantation of
a fertilized ovum. These processes are
in turn dependent on normal produc-
tion of gonadotrophins by the pituitary
gland, and of the sex hormones oestro-
genand progesteroneby the ovaries.
Women become fertile at puberty, and
they remain so until the menopause
around the age of 40 to 50. (See also
fertility drugs; infertility.)
fertility drugsA group of hormonal or
hormone-related drugs used to treat
some types of infertility.
In women, fertility drugs may be given
when abnormal hormone production by
the pituitary gland or ovaries disrupts
ovulationor causes mucus around the
cervix to become so thick that sperm
cannot penetrate it. In men, fertility
drugs are less effective, but they may
be used when abnormal hormone pro-
duction by the pituitary gland or testes
interferes with sperm production. (See
also clomifene; gonadotrophin hor-
mones; testosterone.)
fertilizationThe union of a spermand an
ovum. In natural fertilization, the sperm
and ovum unite in the fallopian tube of
the woman following sexual intercourse.
A single sperm penetrates the ovum by
releasing enzymes that can dissolve the
outer layers of the ovum. Once inside,
the sperm’s nucleus fuses with that of the
ovum, and its empty body shell and tail
drop off. Then, the newly fertilized ovum,
called a zygote, forms an outer layer that
is impenetrable to other sperm. The zy-
gote undergoes repeated cell divisions
as it passes down the fallopian tube to
the uterus, where it implants and will
eventually grow into an embryo.
Fertilization may also occur as a result
of semen being artificially introduced
into the cervix (see artificial insemina-
tion) or may take place in a laboratory
(see in vitro fertilization).rheumatoid arthritis, osteoarthritis,and
gout. Fenbufen is also used to reduce
pain and to help speed recovery follow-
ing muscle and ligament sprains. In
common with other NSAIDs, it can
cause bleeding from the stomach and
may also cause a rash.
fenoprofenA nonsteroidal anti-inflam-
matory drug(NSAID) that is used to
relieve pain and stiffness caused, for
example, by rheumatoid arthritis, osteo-
arthritis, and gout. Fenoprofen is also
used to treat muscle and ligament
sprains; it reduces pain and helps to
speed recovery. In common with many
NSAIDs, fenoprofen may cause irrita-
tion of the stomach.
fentanylAn opioidanalgesic drug that
is given by injection for pain relief dur-
ing surgery and also to enhance general
anaesthesia (see anaesthesia, general).
Fentanyl is also used in the form of a
skin patch to control the severe chronic
pain of conditions such as cancer. In
common with other opioid drugs, fen-
tanyl has side effects that include
depressed breathing, constipation, nau-
sea, and vomiting. The administration
of patches may be associated with local
irritation of the skin.
ferritinA complex of ironand protein,
found mainly in the liver and spleen,
which is the principal form of iron stor-
age in the body.
ferrous fumarateA form of irongiven
in the form of an oral preparation to
treat iron-deficiency anaemia. Ferrous
fumarate can cause diarrhoea, constipa-
tion, and abdominal pain.
ferrous sulphateAnother name for iron
sulphate (see iron).
fertilityThe ability to produce children
without undue difficulty.
A man’s fertility depends on the pro-
duction of normal quantities of healthy
spermin the testes (see testis), which, in
turn, depends on adequate production
of gonadotrophin hormonesby the pitu-
itary gland at the base of the brain.
Fertility in males is also dependent on
the ability to achieve an erectionand to
ejaculate semeninto the vagina during
sexual intercourse. Males become fertile
at puberty and usually remain so, but to
a lesser degree, well into old age.FENOPROFEN FERTILIZATIONF