HORMONAL
CONTRACEPTION
&
FACTORS AFFECTING
EFFECTIVENESS
Jan Bowden
AIMS OF THE SESSION
• Define Bleeding terms.
• Explore what effects the effectiveness of the
combined oral contraceptive pill (CoC).
• Identify best practice
https://www.fsrh.org/documents/ceuguidanceproblematicbleeding
hormonalcontraception/
https://www.fsrh.org/documents/cec-ceu-guidance-womenover40jul-2010/
https://www.fsrh.org/documents/ceuguidanceibd09/
https://www.fsrh.org/documents/ceu-guidance-drug-interactionswith-hormonal-contraception-jan/
THE HORMONAL
METHODS (HMS)
• There are many other effects of the HMs apart from the obvious
contraceptive benefits.
• The common side effects many be positive ones or negative
ones depending on the symptoms and how that affects the
client
• Break through bleeding (BTB) is the most common and irritating
for client and practitioner.
• More common with the combined methods and the POIs
EXPECTED BLEEDING PATTERNS
Method
1st 3 months
Long term
CHC
20% have irregular
bleeding
Usual settles after 1st 3
months. CVR may offer
better cycle control.
Report less bleeding with
use
POP
Unpredictable
1/3 with traditional POP
have a change in
pattern. ?? More
common in DSG users
May not settle with time
DSG 5 in 10 can expect
amenorrhoeic or
infrequent bleeding
POI
Heavy disturbance in
1st 3 months
2 in 10 will be
amenorrhoeic
SDI
Common in 1st 3
months
90% reduction in
blood loss over 1 yr
(Mirena)
BLEEDING PATTERNS
• Clients should be strongly advised about the bleeding
pattern they might expect when starting hormonal
contraception- both short and long term.
• A thorough clinical assessment should be taken when
problematic bleeding is identified to attempt to identify
an underlying cause.
• Those with a STI risk should be offered testing for Chlamydia
& Gonorrhoea.
• If eligible but not participant they should be offered a
smear BUT this is not for diagnosis.
• If history indicates a pregnancy test might be offered.
• An examination is not necessary IF clinical history indicates
no risk for STIs, no concurrent symptoms suggesting a course
and have had no more than 3 months of bleeding since
starting the method
SPECULUM EXAMINATION
Speculum examination may be undertaken if:
• Persistent bleeding or change in bleeding pattern after
3 months of use.
A biopsy should be considered if client is over 45 or under 45
with risk factors of endometrial cancer.
• If medical treatment has failed.
• If no participation in smear screening.
BREAK THROUGH BLEEDING:
• BTB is the most common reason for stopping the CoC.
• Up to 20% have irregular bleeding in 1st 3/12.
• Often CoC users will stop without consultation and run
the risk of an unwanted pregnancy
• Defines as unscheduled bleeding in women using CHC
CLINICALLY IMPORTANT BLEEDING PATTERNS IN
WOMEN AGED
15–44 YEARS
HTTPS://WWW.FSRH.ORG/DOCUMENTS/CEUGUIDANCEPROBLEMATICBLE
EDINGHORMONALCONTRACEPTION/
• SCHEDULED BLEEDING
• Menstruation or regular withdrawal bleeding with combined
hormonal contraception (requiring sanitary protection)
• UNSCHEDULED BLEEDING
• Frequent
• Infrequent
• Prolonged
• Spotting
How do you
define these
terms?
Reference period: a 90 day period of time
during the use of a hormonal method
Frequent
Prolonged
Infrequent
Spotting
It is important to bear in mind the
following:
• Do not simply change the brand of CoC she is currently
using.
• Assess for other causes of BTB first.
• Give reassurance and information as the client may have
concerns regarding, if the CoC is working properly, if she is
pregnant, if she has cancer, if she has an infection.
PREGNANCY RISK AND BTB
• Break through bleeding provided the CoC is
taken properly should not lead to
being
unwanted/unplanned pregnancy.
• A careful history is necessary to elicit pill taking as well
as a careful medical assessment of current health and
past health.
DON’T PEAK……..
What are the causes of breakthrough
bleeding ?
THE MAIN CAUSES OF
This can be remembered as the
BTB:
9 Ds:
• Default.
• Diet.
• Duration.
• Disease.
• Diarrhoea & vomiting.
• Drugs.
• Disturbance of absorption.
• Disorders of
pregnancy.
• Dose
DURATION.
• In general, continue
with the same pill for at
least 3 months as
bleeding may settle in
this time.
• Use a COC with a dose
of EE to provide the best
cycle control.
• May consider increasing
the EE dose up to a
maximum of 35mcg
• May try a different
COC but no evidence
one better than any
other in terms of cycle
control.
• No evidence changing
progestogen dose or
type improves cycle
control but may help
on an individual basis.
• Serum levels of contraceptive
hormones may be increased
or decreased by concomitant
drug use and hormonal
contraceptives may
themselves increase or
decrease serum levels of other
drugs used at the same time .
DRUGS.
1. Pharmacokinetics
2. Pharmacodynamics
• Therefore drug interactions
should be considered when
prescribing medication for
women who may use
hormonal contraception and
could be at risk of
contraceptive failure or other
adverse effects.
1. PHARMACOKINETICS
•
interactions occur when one drug alters the
absorption,distribution, metabolism or excretion of another,
thereby increasing or decreasing its serum concentration and its
effects.
•
The anti-obesity drug orlistat (Xenical®), also available over the
counter as Alli®, may theoretically affect absorption of oral
contraceptives by inducing diarrhoea, that has the potential to
reduce contraceptive efficacy and advises additional
precautions in those with severe diarrhoea.
•
Concomitant medication may also induce vomiting. Women
who vomit within 2 hours of taking an oral contraceptive should
repeat the dose as soon as possible.
•
The general advice for women using oral contraceptives who
have persistent vomiting or severe diarrhoea for more than 24
hours is to follow the instructions for missed pills.
2. PHARMACODYNAMICS
• interactions occur when one drug directly influences
the clinical actions of another by synergy or
antagonism.
• For example, contraceptive steroids might reduce the
efficacy of antihypertensives, lipid-lowering drugs and
antidiabetics because they can have opposing
actions.
ENZYME INDUCTION
• Affects both oestrogen & progestogens.
• Takes place in the liver.
• Certain drugs increase the synthesis of
enzymes.
• Most clinically significant of the 2 mechanisms.
• Most likely to cause pill failure and pregnancy.
• Liver enzyme inducing drugs need special pill
rules or non hormonal method
GUT WALL METABOLISM & REDUCED
ENTERO-HEPATIC CIRCULATION
• Affects oestrogen only.
• Some drugs (particularly antibiotics e.g Rifampicin) kill
natural flora in the gut.
• These flora help with gut wall metabolism allowing
drugs i.e. oestrogen to be absorbed.
• They also assist in the recirculation of conjugated
oestrogens after they have passed through the liver.
BEST PRACTICE
Health professionals supplying hormonal
contraception should ask women about their
current and previous drug use including
prescription, over the counter, herbal, recreational
drugs and dietary supplements.
Women using hormonal contraception should be
informed about the potential for interactions with other
drugs and the need to seek the advice of a health
professional before starting any new drugs.
ENZYME-INDUCING DRUGS
• Enzyme –inducing drugs may increase
metabolism of EE &/or progestogen.
• This can decrease bioavailability and
potentially reduce the contraceptive benefit
of the COC.
• Commonly used enzyme-inducing drugs
include: some antiepileptics inc
Carbamazepine & Phenytoin, Antibiotics such
as Rifampicin, Antiretroviral Ritonavir, EC
ellaOne, Antacids, St John’s Wort
BEST PRACTICE
All women starting enzyme-inducing drugs should be advised to
use a reliable contraceptive method unaffected by enzyme
inducers (e.g. progestogen-only injectable, Cu-IUD or LNGIUS).
Women who do not wish to change from a combined method while
on short-term treatment with an enzyme-inducing drug (and for 28
days after stopping treatment) may opt to continue using a COC
containing at least 30 μg EE, the patch or ring together with
additional contraception.
An extended or tricycling regimen should be used with a hormonefree interval of 4 days.
Additional contraception should be continued for 28 days after
stopping the enzyme-inducing drug.
BEST PRACTICE
Women who do not wish to change from the
progestogen-only pill or implant while on short
term treatment with an enzyme-inducing drug or within
28 days of stopping treatment may opt to continue the
method together with additional contraceptive
precautions (e.g. condoms). Additional precautions
should be continued for 28 days after stopping the
enzyme-inducing drug.
Women using enzyme-inducing drugs who require EC
should be advised of the potential interactions with
oral methods and should be offered a Cu-IUD.
EMERGENCY
CONTRACEPTION
• Women who request oral EC while using enzymeinducing drugs or within 28 days of stopping them
should be advised to take a total of 3 mg LNG
(two 1.5 mg tablets) as a single dose as soon as
possible and within 120 hours of UPSI (use of LNG
>72 hours after UPSI and double dose are outside
the product licence).
• Ulipristal acetate is not advised in women using
enzyme-inducing drugs or who have stopped
• them within the last 28 days.
POINTS TO COVER IN HISTORY TAKING WHEN
ASSESSING UNSCHEDULED BLEEDING.......
• Woman’s concerns
• Current method of
contraception and the
duration of use
• Use of the current
contraceptive method
• Use of medications
(including over-thecounter preparations)
that may interact with the
contraceptive method,
or any illness that may
affect the absorption of
orally administered
hormones
• Cervical screening
history
• Risk of sexual
transmitted infections
(i.e. for those aged <25
years, or at any age
with a new partner, or
more than one partner
in the last year)
• Bleeding pattern
before starting
hormonal
contraception since
starting and currently
• Any other symptoms
suggestive of an
underlying cause (e.g.
abdominal or pelvic
pain, postcoital
bleeding, dyspareunia,
heavy bleeding)
• The possibility of
pregnancy
BTB OF UNKNOWN
CAUSE
• If , after full counselling, full assessment and
investigation, the client is happy to continue will the
CoC this is acceptable.
• Even the strongest & most progestogen dominant pill
will not be sufficient endometrial stability in some
women.
USEFUL SOURCES OF
INFORMATION
ABOUT DRUG INTERACTIONS
• www.bnf.org
• www.medicines.org.uk/emc/
• www.hiv-druginteractions.org/
• www.medicinescomplete.com/mc/index.h
tm