How does GnRH analogue therapy work?

GnRH analogues resemble gonadotrophin-releasing hormone, the messenger that coordinates reproductive hormone release. At first, the medicine can stimulate this pathway; with continued treatment, the pituitary becomes less responsive. Signals that normally prompt the ovaries to make oestrogen then fall, creating a temporary low-oestrogen state sometimes called a medical menopause.

Lower oestrogen can quiet endometriosis-related tissue and ease pelvic pain, but it may also bring hot flushes, vaginal dryness, mood changes or sleep disruption. The effect is temporary and depends on the medicine, dose and treatment plan. Some people receive add-back hormones to reduce low-oestrogen effects while preserving treatment benefits.

Take injections, nasal medicine or implants exactly on the schedule provided, because timing affects hormone suppression. Keep a record of bleeding, pelvic pain, headaches, hot flushes and mood changes. Your clinician may review symptoms and bone health during a longer course, and may discuss add-back treatment or a different option if side effects interfere with daily life.

Contact your treatment team if pain is worsening, bleeding is persistent or unexpected, or low-oestrogen symptoms are difficult to manage. Seek urgent medical help for severe abdominal pain, fainting, breathing difficulty, facial swelling or a sudden severe headache with weakness or speech trouble.

Ask which form of GnRH analogue you will receive, how long suppression is planned, whether add-back hormones are suitable, and how your clinician will monitor symptoms and bone health.