A 21-year-old student presents with vaginal bleeding between her periods. It first occurred 2 months ago and she has had several recurrences. It is usually light and gener- ally lasts from 1 to 3 days.
She has been on the combined oral contraceptive pill (COCP) for 18 months and has regu- lar periods, lasting for 3 days every 28 days. The periods are not heavy or painful. She has not noticed any other discharge. She has not had any bowel or urinary symptoms.
She first had sexual intercourse at the age of 17 years and has been with her current boyfriend for 4 months. There is no pain on intercourse and no postcoital bleeding.
She was seen once before in the gynaecology clinic for pelvic pain and was noted to have a simple ovarian cyst, which subsequently resolved spontaneously. She has no other sig- nificant medical history of note. The general practitioner had arranged an ultrasound assessment prior to referral.
She is slim and looks well. The abdomen is not distended and is non-tender. The external genitalia are normal and on speculum examination a slight blood-stained discharge is noted coming from the cervical os. There is a cervical ectropion which is not bleeding.
Bimanual examination reveals an aneteverted normal size mobile uterus. There is no cervical excitation or adnexal tenderness.
· What is the differential diagnosis?
· How would you further investigate and manage this woman?
The symptom of bleeding between the pill-free interval in a woman taking the combined oral contraceptive pill is known as breakthrough bleeding. It can have many causes and a good history should include, in addition to the history given:
· has she been missing any pills?
· has she taken any other medication which might interefere with the COCP (e.g. antibiotics, enzyme inducers)?
· has she had any intercurrent illnesses causing diarrhoea or vomiting?
· has she ever had any sexually transmitted infections, or been investigated for this?
· how many sexual partners has she had in the last 3 months?
· has she recently changed the COCP that she uses?
The differential diagnosis in a woman with breakthrough bleeding is
· COCP-related causes
· poor compliance
· intercurrent infection causing poor pill absorption
· drug interactions, reducing the COCP efficacy
· inadequate oestrogen component for that woman
· unrelated causes
· cervical ectropion
· sexually transmitted infection – chlamydia, gonorrhoea, trichomonas
· candidal vaginitis
· cervical or endometrial polyp
· bleeding disorder (rare).
The woman should have the following swabs taken:
· endocervical – for chlamydia
· high vaginal – for trichomonas or candida
· endocervical – for gonorrhoea.
(Bacterial vaginosis is another vaginal infection but does not cause bleeding.)
Chlamydia is an increasingly common infection, especially in women aged 18–24 years. It is commonly asymptomatic or may present with minimal symptoms as in this case. It should be tested for with endocervical swab, though urine testing and low vaginal swab testing are also possible. If confirmed, the woman should be treated with doxyxcline or azithromycin and advised that her partner(s) should also be tested and treated at a genitourinary medicine clinic before they resume intercourse.
If the swabs are negative and no other cause can be identified for the breakthrough bleeding, then the woman should be changed to an alternative contraceptive pill. There is no clear solution to suit all women, but possibilities are a phasic pill, an alternative progestogen (such as a ‘third-generation’ progestogen) or a pill containing a higher dose of oestrogen (50 μg rather than 30 μg).