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Biology
(14 - 16)
Birth Control
© SSER Ltd.
Choosing the Right Contraceptive
Once a couple have decided it is the right time to enter into a
sexual relationship, it is vital that before any sexual penetration
takes place, they discuss the most appropriate form of
contraception. Abstinence is classed as a form of birth control.
Contraception means:
a method of preventing an unwanted pregnancy.
The Condom
Choosing the right method of contraception depends on a
couples’ religious and personal beliefs. There are many different
methods of contraception available, e.g. the condom
A condom is a rubber sheath rolled
down over the penis before intercourse.
During intercourse, the condom
prevents sperm entering the vagina.
The Condom
After intercourse, the penis has to be withdrawn carefully, and
the condom (together with the semen), disposed of in a sensible
manner.
Care has to be taken to ensure that the condom
is not torn or split, as this may cause the sperm
to escape into the vagina, possibly
resulting in pregnancy.
Condoms and 15 Year Olds
Study the following graph to find out more about the use of condoms
by 15 year old teenagers in Europe…
Schools give condoms to 14 year olds!
I
n some counties around the country,
as part of a sex education programme,
schools are offering boys and girls, as
young as 14, access to condoms.
One local Headteacher said “the aim is to
reduce teenage pregnancies and to protect
teenagers from sexual infections”.
However, some local parents
are appalled by the
scheme...
What do you think?
The Diaphragm (Cap)
The diaphragm is a rubber cap which is placed inside the vagina,
and moved up over the cervix.
The first time a diaphragm is used it
should be fitted by a nurse.
The diaphragm must be inserted some
time before sexual intercourse, and
remain in the vagina for 6 to 8 hours
after a man’s last ejaculation.
A diaphragm should be used together
with a spermicide, which kills sperm.
Spermicides can be in a gel or cream form.
Spermicides can also be used with a condom.
The IUD (Coil)
The Intrauterine device (IUD or coil) is 98% effective
and sits in the woman’s uterus for up to 10 years and
prevents her from getting pregnant in three main ways...
 prevents sperm from getting through to
the womb and into the fallopian tubes
 alters the secretions (mucus) in the cervix,
so creating a further barrier to the sperm
 irritates the womb lining - it is unable to
‘accept’ an embryo.
An IUD used with hormones is called an Intrauterine system
(IUS), is 99% effective and this combined system can be used for
up to 5 years. IUDs and IUSs must be administered by a doctor
and whereas an IUD can cause heavy periods the IUS can cause
tender breasts and acne.
The Femidom
The femidom can be likened to a female condom, hence its name.
A femidom is a rubber sheath inserted into the vagina.
The closed end goes inside the vagina and
the open end is left outside the vagina.
During intercourse the femidom
physically prevents sperm entering
the vagina.
After intercourse, the femidom
containing the semen has to be removed
carefully, and disposed of in a sensible
manner.
Care has to be taken to ensure that the femidom
is not torn or split, as this may cause the sperm to
escape into the vagina, possibly resulting in pregnancy.
Using Sex Hormones as Contraceptives
Oral contraceptives, usually known as ‘the pill’ prevent sperm
from fertilising ova, i.e. they prevent conception.
They may contain oestrogen and/or progesterone
which prevent conception in several ways:
 Oestrogen prevents ovulation by
inhibiting the production of
follicle-stimulating hormone (FSH) by
the pituitary gland. No ova will develop.
 Oestrogen causes a sticky substance to block the uterus
entrance at the cervix, preventing sperm from entering.
 Progesterone makes the uterus lining so thick that an embryo
(if conception occurred) cannot implant.
Using Sex Hormones as Contraceptives
Oestrogen is so effective at inhibiting
the production of FSH and thereby
the production of ova that a section
through the ovary of a female taking
the combined pill reveals only
immature follicles.
Notice that in this sectional view of
an ovary, mature follicles and the
corpus luteum are absent – this is
enough to act as a contraceptive as
ovulation cannot occur.
Ovary
The Pill
There are two main types of contraceptive pill - each is defined by
the hormones they contain...
1.
Progesterone Only Pill
- contains only progesterone
2.
The Combined Pill
contains both oestrogen and progesterone
Both types of pill have to be taken every day.
Progesterone Only Pill
The ‘progesterone only’ pill (mini-pill) prevents the release of an
egg cell, and makes it more difficult for an embryo to be
implanted in the womb. It is 99% effective and easy to take.
It also alters the cervical mucus so that sperm cannot move
easily through it. Both types of pill can have side effects such as
feeling sick and gaining weight.
Some reports even suggest that long term use of the
contraceptive pill could increase the risk of cervical cancer.
The Combined Pill
The ‘combined pill’ contains two hormones (a progestogen and an
oestrogen) and prevents ovulation (production of an egg cell).
The combined pill also makes it difficult for the embryo, should
one be produced, to be implanted in the womb.
Medical Concerns About the Combined Pill
Evidence suggests that the
oestrogen levels in the combined pill
can interfere with the blood clotting
mechanism and increase the risk of
thrombosis, heart attacks and
strokes.
Therefore, oestrogen levels in
A blood clot forming inside a
capillary – this could lead to
the combined pill are kept as low
major clot (thrombosis)
as possible and a different kind
of pill, the mini-pill, has been developed.
The mini-pill is a progesterone-only pill that appears to act by
interfering with development of the egg cell.
The Morning After Pill
The morning after pill is taken after
unprotected sexual intercourse has taken place.
The pill has to be taken within 72 hours
after intercourse has taken place.
It contains a high dose of progesterone,
and prevents an embryo from being
implanted.
The initial high level of progesterone in the female body
stimulates development of the lining of the womb.
The sudden drop in progesterone in the days after the pill has
been taken, prevents implantation of a potential embryo into the
lining of the womb.
Injection - Progesterone
The progesterone injection can last for 2-3 months and is 99%
effective. The injection prevents implantation of the embryo in
the uterus wall.
The progesterone injection
must be administered by a
doctor and can cause
irregular or heavy periods.
Contraceptive Implant
The contraceptive implant is a rod the size of a thin matchstick
and it contains a hormone called etonorgestrel. The implant is
nearly 100% effective and lasts for up to 3 years.
A local anaesthetic is injected into your skin, and then the rod is
pushed in using a special needle. The implant should be put in
about 8-10 cm above the elbow. The whole procedure takes just
three minutes and the patient can go home immediately
afterwards.
After the procedure
about 3.6% of women,
get bruising, swelling,
redness or soreness at
the site of insertion.
The Withdrawal Method
At the moment he is about to have an orgasm, the male removes
his penis from the female’s vagina, ensuring that no semen
(containing the sperm) enters the vagina.
However, this moment is not always clear and errors can result in
pregnancy.
Sperm are often released in lubricant fluid prior to ejaculation.
The Rhythm Method
The female has to work out the time in her menstrual cycle
when ovulation is due.
At about this time, the couple
refrain from having vaginal
intercourse.
As ovulation is not always clear,
any errors in the female’s
calculations can lead to pregnancy.
Male Sterilisation - Vasectomy
In this minor surgical operation the sperm ducts are both cut so
that semen will not contain active sperm. It can be reversed in
many cases. This operation should not be undertaken if there is
any chance you may want children in the future.
Sperm duct
(vas deferens)
Cut here
x
x
Cut here
Female Sterilisation - Tubal Ligation
In this major surgical operation the oviducts are both cut, clipped
or cauterized so that sperm cannot reach an ovum.
It can be reversed with some degree of success. This operation
should not be undertaken if there is a chance the woman may
want children in the future.
Fallopian tube
(oviduct)
x
Cut here
tubal clip
A hysterectomy is the surgical
removal of the uterus - it
permanently prevents
pregnancy and diseases
such as uterine cancer.
x
Cut here
Reliability of Different Contraceptives
Run the following graph to find out more about the failure rates
of different types of contraceptive…
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