is also known as post coital contraception and can prevent pregnancy after unprotected
intercourse. It is not quite true to say 'the morning after the night before'
as it can actually work up to 72 hours of unprotected sex.
There are two forms
of emergency contraception - one is by way of hormonal contraceptive tablets
and the other is by insertion of a copper coil or intrauterine device (IUD).
The emergency contraceptive
pills are high dose oestrogen pills and are taken in two separate doses. The
first dose must be taken within 72 hours of unprotected intercourse followed
by the second dose 12 hours later. It is important to make sure that there were
no previous bouts of unprotected intercourse prior to this 72-hour window. If
this was the case the woman could already be pregnant and the pills would be
contraindicated. The IUD can be inserted up to five days after unprotected intercourse
in the hope of preventing pregnancy.
Use of emergency
Millions of women
around the world have used emergency contraceptives effectively. However, it
must be stressed that this is an emergency form of contraception and does not
replace the ever-popular effective methods of regular contraception.
for emergency contraception
sex: where consensual sex occurred with no contraception; rape or sexual assault
with risk of pregnancy; coitus interruptus.
- Potential barrier
- Potential pill
failure when alternative methods have not been used or have failed, eg. antibiotics
used with pill.
Mode of action
of emergency contraception pills
These high dose
hormones act by delaying or inhibiting ovulation and/or by altering the transport
of sperm along the tubes. They may also alter the lining of the endometrium
so preventing implantation.
This is the most
common method of emergency contraception and is named after a Canadian professor,
A. Yuzpe, who first discovered its efficacy back in 1974. Two doses of high
dose hormones are taken, followed by the same dose exactly 12 hours later. In
England the term PC4 is used for emergency contraception. However, this is not
licensed for similar use in this country, so usually the doctor will either
supply the pills directly from the surgery or will give instructions on how
to take pills from a brand packet.
to the Yuzpe regime
contraceptive pills are not effective if the woman is already pregnant. It is
thought that on the current available evidence that the amount of hormone used
in the Yuzpe method is so small that it should not have a clinical impact on
risk of use with similar contraindications for the combined oral contraception.
This would include severe cardiovascular complications, acute focal migraine
or severe liver disease. However, these and other conditions are included amongst
the contraindications in any data associated with emergency contraception, so
it is up to the doctor at the time of prescribing to assess these risk factors.
Similarly there are no drug interactions with the Yuzpe method that would contraindicate
Efficacy of Yuzpe
It is thought that
this combined oestrogen progestogen method prevents at least 74% of pregnancies
when treatment is initiated within 72 hours. A 1998 WHO trial also found that
this combination method was more effective when treatment was initiated within
24 hours of unprotected sex.
Some women experience
nausea and even vomiting when taking this high dose hormone method. Some centres
routinely prescribe medication to counteract the nausea and vomiting. Examples
used are Domperidone (but this can cause unusual side effects, affecting posture).
Some centres prescribe Cyclizine, and other centres prescribe Motilium.
It is important
to stress when prescribing this method of contraception that it only prevents
pregnancy from this bout of unprotected pregnancy. It does not protect against
pregnancy for the remainder of the menstrual cycle. Women must use an effective
method of contraception or avoid sex for the remainder of the cycle until they
get their next period.
Timing of next
period after Yuzpe method
Most women will
start their next period within three days of the expected date. Some start early
and some may be up to seven days late. If, however a woman does not have a period
10 days after the expected date she should return for a pregnancy test. It is
also possible that there may be some spotting before a full period comes after
taking this high dose emergency contraception.
A copper IUD is
inserted up to five days after unprotected intercourse. Again this must be fitted
by a trained doctor. Awareness of post insertion pelvic infection must be considered.
Some centres do testing for sexually transmitted disease before fitting an IUD.
Obviously if positive, appropriate management must be followed.
Efficacy of IUD
This is in fact,
higher than emergency contraceptive hormones with a failure rate of less than
These include pain
and heavier bleeding. However, an IUD fitted post coitally can be removed at
the beginning of the next period if a woman does not wish to continue with it
as a form of contraception.
pregnancy is a contraindication for fitting an IUD. If a copper IUD is being
fitted sensitivity to copper would contraindicate its use. Again expert fitting
How an IUD works
The IUD alters
tubal and uterine transport and affects the sperm and ovum so fertilisation
does not occur. Post coital use of an IUD does involve the same mechanism in
some cases, but is more likely to interfere with implantation.
Since both methods
may fail, women should discuss with their doctors any signs of pregnancy after
use of either method. Signs include a missed period, nausea, inexplicable fatigue,
sore breasts, headaches and frequency of passing water. If pregnant, women should
attend their doctors for advice. Emergency contraception does not prevent ectopic
pregnancy, where the pregnancy develops outside of the womb and such a pregnancy
should be seen by a doctor at the earliest possible signs. This includes pain
on either side of the abdomen with spotting, especially after a light or missed
menstrual period and associated dizziness.
There is a progestogen-only
form of emergency contraception which is not licensed in this country. The recommended
dose is 75µg, which would necessitate taking a huge number of pills, in the
order of 25 pills at one go. Again the method is to take the pills within 72
hours of unprotected sex and two doses are taken 12 hours apart. The efficacy
of this regime is thought to be about 86%. Commonly associated side effects
of this method include nausea and vomiting. Again it is contraindicated if pregnancy
is established. There is thought to be no other contraindication.
and other follow-up
It is important
that these visits for emergency contraception are used as a forum for discussing
future contraception. Options should be discussed, and even prescribed - depending
on the consultation. Obviously, precautions must be taken or intercourse avoided
until the next period when the appropriate form of contraception is started.
Your local GP in
many cases will prescribe emergency contraception. Phone the doctor's secretary
to check in advance. If not, most doctors who advertise in the Yellow Pages
prescribe emergency contraception. Family planning clinics around the country
also prescribe emergency contraception.
Written by Dr Claire
McNicholas, general practitioner, Dublin
to top of page
Back to Features
Back to Homepage