27th June 2023

Intermenstrual bleeding

The cause of IMB may become obvious from the history. One important cause to rule out is ectopic pregnancy or (less commonly) gestational trophoblastic disease – both would be associated with a positive pregnancy test. Causes can be grouped by the site of the reproductive tract involved, for example, polyps can be uterine or cervical. Fibroids are a common cause occurring in 25% of women of reproductive age.

Iatrogenic causes should be considered, including:

• Tamoxifen – an anti-oestrogen drug typically used in pre- and peri-menopausal women with oestrogen-receptor positive breast cancer
• Poor adherence to the taking of oral contraceptive pills
• Drugs affecting clotting, including serotonin selective reuptake inhibitors (SSRIs), anticoagulants and corticosteroids