Non-hormonal methods of preventing
Doc Brown's Biology exam study revision notes
There are various sections to work through,
after 1 they can be read and studied in any order.
of biology notes on human sexual reproduction
(5) Non-hormonal methods of preventing
Barrier methods to stop the
sperm ever meeting an egg, hence stop fertilisation of egg and therefore
All such devices must be
carefully fitted in place before sexual intercourse takes place.
(i) Condoms made of thin
latex are worn over
the penis during intercourse to stop sperm entering the vagina.
Female condoms are worn inside the vagina.
Note that male condoms is
the best form of contraception that protect you against sexually
transmitted diseases, not 100% effective, but many other
contraception methods do not protect against STDs at all.
(ii) A diaphragm is a
shallow flexible plastic cup or dome shaped device that fits over the
opening of cervix making a barrier to
the entrance to the uterus.
The diaphragm prevents sperm reaching an
egg and it can be used in conjunction with a spermicide that kills
(iii) A femidom is female condom are made
from soft, thin synthetic latex or latex.
The femidom is worn inside the vagina to prevent
semen getting to the womb and must be put in place before sexual
Killing the sperm
(i) It is possible to use a spermicide on its own as a contraceptive, but is only 70-80%
effective, much less than the other contraception methods previously
(ii) Copper IUDs
that kill sperm and prevent them surviving in the uterus,
and so can never fertilise a released egg (non-hormonal
Sterilisation - requires a
This involves cutting or tying
tubes in the reproductive system ...
(i) female (female
sterilisation) - the
fallopian tubes (oviducts) which connect the ovaries to the uterus,
are cut, sealed or blocked by an operation so that eggs
cannot be released into the uterus.
(ii) male (male vasectomy) - the sperm
duct tube that connects the testes with the penis is cut, sealed
or tied so that sperm cannot
be mixed with semen and injected into the vagina in sexual
These are surgical procedures
with a permanent effect -there is only a very small chance of
the tubes joining up again.
Successful surgery is nearly 100%
effective, and very difficult to reverse.
'Natural' methods of family
planning, unprotected sex and the
This involves knowing when the
woman is most fertile within the 28 day menstrual cycle.
the idea is to avoid sexual intercourse during these fertile
At around 14 days when the
egg is released (ovulation) there is a slight increase in
By estimating when ovulation
might occur, by avoiding sexual intercourse at that time, you
reduce the chance of fertilising an egg.
However, it is not very effective,
because eggs and sperm can live for several days and a woman's
cycle can be irregular, but it is used by people
who think that barrier and hormonal methods are unnatural (or
considered ethically wrong by some religious teachings).
The cervical mucus method is a way to
identify fertile times to help you gauge the best days to have
or avoid unprotected sex and require careful observation of
mucus patterns in the menstrual cycle.
Before ovulation, cervical secretions change
creating a situation that helps sperm travel through the
cervix, uterus and fallopian tubes to the egg.
By recognizing changes in the cervical
mucus, the woman can try to pinpoint when you're most likely
to ovulate, hence most likely to conceive.
If the woman is hoping to get pregnant, she can use the
cervical mucus method to determine the best days to have
Conversely, if the woman wants to avoid
pregnancy, the cervical mucus method can help predict which
days to avoid having unprotected sex..
The man can also remove his
penis before ejaculation to prevent sperm entering the uterus,
but that requires a good deal of self control.
No sexual intercourse at all, is the only truly 100%
guaranteed pregnancy prevention!
TOP OF PAGE
of biology notes on human sexual reproduction
INDEX of all my BIOLOGY NOTES
This is a BIG website, so try using the [SEARCH
BOX], it maybe quicker than the many indexes!
brown - comments - query?
UK KS3 Science Quizzes for
KS3 science students aged ~11-14, ~US grades 6, 7 and 8
Biology * Chemistry
* Physics UK
GCSE/IGCSE students age ~14-16, ~US grades 9-10
Advanced Level Chemistry
for pre-university ~16-18 ~US grades 11-12, K12 Honors
Find your GCSE/IGCSE
science course for more help links to all science revision notes
mobile phone or ipad etc. in 'landscape' mode?
Website content © Dr
Phil Brown 2000+. All copyrights reserved on revision notes, images,
quizzes, worksheets etc. Copying of website material is NOT
permitted. Exam revision summaries & references to science course specifications