Case 96: Contraception

 CASE 96: CONTRACEPTION

History

A woman has been referred by her GP for contraceptive advice. She is 28 years old and had

a thromboembolism at the age of 24 years following a triathlon event and long rail journey

home. Prior to this she was using the combined oral contraceptive pill for contraception. She

remains sexually active and uses condoms reliably but has recently had an unplanned pregnancy as a result of a split condom, despite using the emergency contraception after the event.

She terminated the pregnancy and feels deeply upset about the experience.

She is desperate for reliable contraception. She was advised to try the copper intrauterine

contraception device but has read that this may worsen her already heavy periods. She has

also discussed the progesterone only pill with her GP but is scared that she may forget to take

it at precisely the right time every day and therefore be at risk of further pregnancy.

Her cycle is regular, bleeding for 5 days every 30 days. She has had no other pregnancies and

no relevant gynaecological problems. She has no other significant medical history and takes

no regular medications.

She works as a marketing consultant with a fairly busy overseas travel schedule. She has been

in a stable relationship with her partner for 3 years, but they do not plan to start a family in

the near future.

Question

• What are the contraceptive options to her and their relative advantages and

disadvantages?100 Cases in Obstetrics and Gynaecology

276

ANSWER 96

Oestrogen-containing contraception is contraindicated for this woman because of her history of venous thromboembolism, even though this was apparently provoked by the situational events at the time. This means that the options are progesterone only methods or

non-hormonal methods.

Non-hormonal methods

Although her compliance with barrier contraception is good, she has had a distressing experience as a result of a split condom and failure of the emergency contraception, so these

are not realistic options to continue. The copper intrauterine contraceptive device would be

effective in preventing pregnancy though likely to worsen her periods, as she has read, and

therefore would not be a first-line choice.

The progesterone only pill is reasonably effective (Pearl index 0.3–4/100 women-years) but

this is highly correlated with compliance. In this woman’s case the busy schedule and travel

may mean that she is unable to reliably take the pill within the necessary 3 h time frame. Thus

she may be better advised to consider a long-acting method.

The five methods of long-acting reversible contraception include the copper coil, the contraceptive vaginal ring, the contraceptive implant, the contraceptive injection and the levonorgestrel-containing intrauterine system (IUS).

Copper intrauterine device

As described this is unlikely to be a suitable option for this woman as she already has menorrhagia which is likely to be worsened by the coil.

Contraceptive vaginal ring

This flexible transparent plastic ring is placed in the vagina where it releases oestrogen and

progestogen. It is left in situ for 21 days and then removed for 7 days before a further ring is

inserted. It is highly effective (Pearl index less than 1) but contraindicated in this case because

of the history of thrombosis.

Intrauterine system (IUS)

The advantages are the high efficacy (Pearl index 0.2) and the fact that it can be left in situ

for up to 5 years. Fertility returns within a few days following removal. Within 12 months of

device insertion, many women are oligoamenorrhoeic or amenorrhoeic which is an advantage to some though disconcerting to others.

Disadvantages are that it may cause discomfort at fitting (though uterine perforation is

rare) and importantly can be associated with irregular bleeding or spotting during the first

6 months of use. Although the amount of systemic levonorgestrel absorption is low, some

women report progestogenic side effects of acne, low mood or bloating.

Contraceptive implant

The contraceptive subdermal implant is a 4 cm flexible rod containing etonogestrel which

is inserted into the woman’s upper inner arm under local anaesthetic. It has the advantage

of being highly effective (Pearl index less than 0.5) and can be left in situ for 3 years before

replacement or removal. There is no delay in fertility after removal. The main disadvantage is

the frequency (50 per cent) of bleeding irregularity which may be heavy or erratic. HoweverCase 96: Contraception

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unlike the contraceptive injection, the implant can be removed to resolve this. Acne can

worsen with the implant but changes in mood, weight, libido and headaches are not proven

side effects.

Contraceptive injection

The contraceptive injection involves a deep intramuscular dose of depot medroxyprogesterone

acetate every 12 weeks or norethisterone enanthate every 8 weeks. The advantages are the ease of

administration compared with the implant or IUS and high efficacy (Pearl index less than 0.5).

Amenorrhoea is very common but many women may experience persistent irregular bleeding. There is a significant increase in weight with injectable contraceptives (up to 2–3 kg in 1

year) and a small loss in bone density (which recovers on discontinuation). In addition there

may be a delayed return of fertility for up to 1 year following discontinuation.

! Considerations when making a decision about contraceptive methods

• Contraceptive efficacy (commonly described using the Pearl index = number

of pregnancies if 100 women used this method with perfect compliance for 12

months)

• Likely duration of use

• Risks and side effects

• Individual contraindications for use (e.g. previous thrombosis or migraine with

aura and oestrogen contraceptives)

• Non-contraceptive benefits (e.g. prevention of sexually transmitted infection with

condoms, control of menorrhagia with combined contraceptive pill)

• Procedure for initiation/insertion/removal

• Possible delay in fertility after use

KEY POINTS

• History of venous thromboembolism is an absolute contraindication for oestrogen

containing contraception.

• Progesterone contraception is not contraindicated if there is a thrombosis risk.

• Long-acting reversible contraceptives (LARC), such as the levonorgestrel intrauterine system or progestogen implant, are effective and popular.