Case 97: Unprotected intercourse

 CASE 97: UNPROTECTED INTERCOURSE

History

A 24-year-old woman presents reporting a split condom during intercourse 22 h ago. She is

now worried about pregnancy.

Her last menstrual period started 10 days ago and she has a regular 28-day menstrual cycle.

She has never been pregnant in the past. She has been with this partner for the last 6 weeks.

She is generally healthy with no relevant previous medical history although is overweight

with a body mass index of 31.

Examination

Abdominal examination is unremarkable and internal examination is not indicated.

INVESTIGATIONS

Urinary pregnancy test: negative

Questions

• What can you advise or offer this woman in regard to her concern about avoiding pregnancy?

• What other considerations are there in your clinical care apart from those relating

to possible unplanned pregnancy and how would you deal with these?100 Cases in Obstetrics and Gynaecology

280

ANSWER 97

This woman needs to be advised regarding emergency contraceptive options but first you

must ascertain whether there is a risk that she is already pregnant.

Although the pregnancy test is negative, if she had become pregnant in the last 2 weeks then

she could be at the implantation stage, without the urinary human chorionic gonadotrophin

(hCG) level being high enough to result in a positive pregnancy test. This is known as a luteal

phase pregnancy.

In this particular case however a luteal phase pregnancy is very unlikely as the last period was

only 10 days ago and therefore ovulation would not yet be expected.

The options for emergency contraception with risks and benefits are listed below.

Emergency contraceptive pill

This is taken as a single tablet as soon as possible after unprotected intercourse. The single

1.5 mg levonorgestrel preparation is licensed for use for up to 72 h after intercourse and the

single 30 mg ulipristal acetate preparation is licensed for 120 h after intercourse.

The emergency pill prevents pregnancy in 97–99 per cent of women and this is thought to be

by inhibiting ovulation. However it does not prevent pregnancies from subsequent unprotected sex in that cycle.

There are no absolute medical contraindications for the emergency contraceptive pill, but it

should not be taken by women taking enzyme-inducing drugs and ulipristal acetate should

not be used in women taking drugs that increase the gastric pH, such as antacids.

A few women vomit within 2 h after the emergency contraceptive pill, in which case they

should be offered a further dose or the copper-bearing intrauterine device.

Emergency intrauterine contraceptive device (IUCD)

The standard copper-bearing intrauterine device (‘coil’) can be inserted up to 5 days after

sexual intercourse or up to 5 days after the earliest expected date of ovulation, whichever is

the later. It should be left until at least the onset of the next period.

The IUCD is the most effective emergency contraceptive, preventing over 99 per cent of pregnancies, but may be associated with pain on or after insertion as well as risk of infection.

Prophylactic antibiotics should therefore be considered at insertion. The advantage of this

method of emergency contraception is that it provides ongoing contraception for as long as

necessary until the device needs changing (usually 5 years).

! What the choice of emergency contraception depends on

• Efficacy of method

• Last menstrual period and cycle length

• Number and timing of episodes of unprotected intercourse

• Previous emergency contraceptive use within cycle (ulipristal acetate can only be

used once per cycle)

• Need for additional precautions/ongoing contraception

• Drug interactions

• Individual choiceCase 97: Unprotected intercourse

281

Whichever emergency contraceptive is used, the woman should be advised to take a pregnancy test in 3 weeks if a normal period has not occurred.

Non-contraceptive concerns

A woman who has had unprotected intercourse is at risk of sexually transmitted infection.

Investigation with genital swabs at the time of first presentation should be considered for

pre-existing infection. She should however be advised to be tested for chlamydia and gonorrhea infection again after 3 weeks or longer for blood-borne infections such as hepatitis B

and HIV.

Ongoing contraceptive needs should also always be discussed with any woman requesting

emergency contraception.

KEY POINTS

• Remember that a pregnancy conceived at the time of ovulation (day 14) will only

register with a positive pregnancy test from around day 25.

• The copper intrauterine contraceptive device (inserted within 5 days of intercourse) is more effective at preventing pregnancy than the emergency contraceptive progestogen pill.