As part of preparing your body to accept IVF treatments, sometimes you’ll need to take drugs that suppress the natural hormones your body produces

There are several different types of cycle-suppressing drugs. They alter the levels of hormones that control ovulation, suppressing (in a process called ‘down regulation’) your natural menstrual cycle. Your fertility clinic will recommend which, if any, is appropriate for you.

These can include one or more of:

Gonadotrophin-releasing hormone (GnRH) analogues^{2, 3}

This type of treatment blocks the release of a hormone produced by the pituitary gland at the base of the brain, which controls naturally occurring ovulation – the release of an egg by your ovaries. Blocking the release of this hormone therefore down regulates your natural monthly cycle, and stops the release of eggs from your ovaries until they are ready to be collected. There are two forms of GnRH analogues:

– GnRH agonists:

• Commonly used in ‘long’ IVF cycles
• Usually taken for a week or so before and after the first day of your period – they are also taken for about two weeks after your period
• Available as a nasal spray (several times a day), a daily injection or a monthly injection

– GnRH antagonists

• Commonly used in ‘short’ IVF cycles
• Usually taken for about a week after the first day of your period
• Taken as daily injections

References:

UK-RMMH-2100019 | Date of preparation: June 2021