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The Lister Fertility Clinic
Approximately one in six couples have difficulty achieving a pregnancy. It has
been found that female factors are responsible in 30% of cases, male factors
account for a
further 30%, combined male and female factors account for 20% and the remaining
20% of cases are unexplained.
Under normal circumstances, the chances of pregnancy occurring as a result of
unprotected intercourse during the fertile time of the cycle are about 25% per
month. After 12 months of trying, approximately 80% of couples will have
conceived.
Unexplained infertility affects 20-25% of infertile couples. In the majority of
these cases, the failure to reach a diagnosis is not due to inadequate
investigations, but is
probably due to other factors which cannot be assessed using conventional tests.
For example, it is not currently possible to determine if the eggs are actually
released at the time of supposed ovulation; if the fallopian tubes are able to
pick up the eggs; if the sperm are capable of reaching the site of fertilisation;
or if the eggs can be fertilised by the sperm.
In cases of unexplained infertility, assisted conception in the form of IVF is
both diagnostic and therapeutic. For example, if the eggs are not released
naturally, we release them by performing egg collection; if the tubes are not
picking up the eggs, we bypass them when we perform IVF, if the sperm cannot
reach the site of fertilisation, we overcome this by placing it with the eggs.
Finally, we can confirm fertilisation by IVF.
www.ivf.org.uk
Chelsea Bridge Road,
London SW1W 8RH
Human Fertilisation and Embryology Authority
For a woman to conceive, certain things have to happen: intercourse must take
place around the time when an egg is released from your ovary; the systems that
produce
eggs and sperm have to be working at optimum levels; and your hormones must be
balanced. If you are not using contraception and having intercourse regularly,
95% of
couples will conceive within two years.
You can find out when you are most fertile from the ovulation chart in the Guide
to infertility. Eggs live and can be fertilised for 12-24 hours after being
released, and sperm can stay alive and active in your body for 12-48 hours after
ejaculation, so you don't have to have intercourse at the exact moment of
ovulation to get pregnant.
It just takes one sperm to fertilise the egg for you to become pregnant.
Although millions of sperm are released upon ejaculation, few survive the
journey through the cervix, uterus and fallopian tubes to fertilise the egg. If
fertilisation does not take place, or if the fertilised egg does not attach
itself to the lining of the womb, it breaks down and your womb lining is shed: a
period.
Eggs are usually collected by ultrasound guidance, which takes around 30
minutes. Your doctor will insert a thin needle through your vagina into each
ovary. The eggs will be sucked into the needle. Very occasionally, eggs will be
collected by laparoscopy (a small telescope with a light attached). This
procedure involves making a small cut in your stomach and extracting the eggs
with a fine needle, as before.
www.hfea.gov.uk
21 Bloomsbury Street
London
WC1B 3HF |
